Document And Entity Information
v4.2.117.0
Document And Entity Information (USD $)
12 Months Ended
Sep. 30, 2011
Nov. 17, 2011
Mar. 31, 2011
Document And Entity Information [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Sep. 30, 2011
Document Fiscal Year Focus 2011    
Document Fiscal Period Focus FY    
Entity Registrant Name F5 NETWORKS INC    
Entity Central Index Key 0001048695    
Current Fiscal Year End Date --09-30    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Filer Category Large Accelerated Filer    
Entity Public Float     $ 8,230,608,207
Entity Common Stock, Shares Outstanding   79,484,124  

Consolidated Balance Sheets
v4.2.117.0
Consolidated Balance Sheets (USD $)
In Thousands
Sep. 30, 2011
Sep. 30, 2010
ASSETS    
Cash and cash equivalents $ 216,784 $ 168,754
Short-term investments 325,766 259,742
Accounts receivable, net of allowances of $2,898 and $4,319 165,676 112,132
Inventories 17,149 18,815
Deferred tax assets 8,391 8,767
Other current assets 29,907 37,745
Total current assets 763,673 605,955
Property and equipment, net 47,998 34,157
Long-term investments 470,203 433,570
Deferred tax assets 34,762 37,864
Goodwill 234,691 234,700
Other assets, net 17,222 15,946
Total assets 1,568,549 1,362,192
LIABILITIES AND SHAREHOLDERS' EQUITY    
Accounts payable 33,525 21,180
Accrued liabilities 67,902 61,768
Deferred revenue 270,880 204,137
Total current liabilities 372,307 287,085
Other long-term liabilities 18,388 16,153
Deferred revenue, long-term 72,418 55,256
Total long-term liabilities 90,806 71,409
Commitments and contingencies (Note 7)    
Shareholders' equity    
Preferred stock, no par value; 10,000 shares authorized, no shares outstanding    
Common stock, no par value; 200,000 shares authorized, 79,145 and 80,355 shares issued and outstanding 380,737 517,215
Accumulated other comprehensive loss (6,422) (3,241)
Retained earnings 731,121 489,724
Total shareholders' equity 1,105,436 1,003,698
Total liabilities and shareholders' equity $ 1,568,549 $ 1,362,192

Consolidated Balance Sheets (Parenthetical)
v4.2.117.0
Consolidated Balance Sheets (Parenthetical) (USD $)
In Thousands, except Per Share data
Sep. 30, 2011
Sep. 30, 2010
Consolidated Balance Sheets [Abstract]    
Accounts receivable, allowances $ 2,898 $ 4,319
Preferred stock, par value $ 0 $ 0
Preferred stock, shares authorized 10,000 10,000
Preferred stock, shares outstanding 0 0
Common stock, par value $ 0 $ 0
Common stock, shares authorized 200,000 200,000
Common stock, shares issued 79,145 80,355
Common stock, shares outstanding 79,145 80,355

Consolidated Income Statements
v4.2.117.0
Consolidated Income Statements (USD $)
In Thousands, except Per Share data
3 Months Ended 12 Months Ended
Sep. 30, 2011
Jun. 30, 2011
Mar. 31, 2011
Dec. 31, 2010
Sep. 30, 2010
Jun. 30, 2010
Mar. 31, 2010
Dec. 31, 2009
Mar. 31, 2009
Sep. 30, 2011
Sep. 30, 2010
Sep. 30, 2009
Net revenues                        
Products $ 197,446 $ 179,327 $ 173,710 $ 171,492 $ 164,972 $ 147,393 $ 129,559 $ 119,218   $ 721,975 $ 561,142 $ 406,529
Services 117,169 111,386 103,862 97,442 89,302 83,081 76,509 71,938   429,859 320,830 246,550
Total 314,615 290,713 277,572 268,934 254,274 230,474 206,068 191,156   1,151,834 881,972 653,079
Cost of net revenues                        
Products 34,485 31,803 31,423 31,614 31,045 29,328 27,419 26,042   129,325 113,834 95,209
Services 21,435 20,645 19,250 17,349 15,783 15,251 13,997 13,087   78,679 58,118 47,517
Total 55,920 52,448 50,673 48,963 46,828 44,579 41,416 39,129   208,004 171,952 142,726
Gross profit 258,695 238,265 226,899 219,971 207,446 185,895 164,652 152,027   943,830 710,020 510,353
Operating expenses                        
Sales and marketing 100,945 93,633 89,332 86,825 80,696 77,219 69,644 65,642   370,735 293,201 225,193
Research and development 36,552 35,245 34,507 32,606 31,571 30,889 29,134 26,720   138,910 118,314 103,664
General and administrative 21,867 21,126 19,846 20,684 18,876 17,658 16,016 15,953   83,523 68,503 55,243
Restructuring charges                 4,300     4,329
Total 159,364 150,004 143,685 140,115 131,143 125,766 114,794 108,315   593,168 480,018 388,429
Income from operations 99,331 88,261 83,214 79,856 76,303 60,129 49,858 43,712   350,662 230,002 121,924
Other income, net 4,087 1,889 1,568 2,545 68 3,561 2,291 1,705   10,089 7,625 9,724
Income before income taxes 103,418 90,150 84,782 82,401 76,371 63,690 52,149 45,417   360,751 237,627 131,648
Provision for income taxes 35,808 27,601 29,207 26,738 28,136 23,195 19,005 16,138   119,354 86,474 40,113
Net income $ 67,610 $ 62,549 $ 55,575 $ 55,663 $ 48,235 $ 40,495 $ 33,144 $ 29,279   $ 241,397 $ 151,153 $ 91,535
Net income per share - basic $ 0.84 $ 0.77 $ 0.69 $ 0.69 $ 0.60 $ 0.51 $ 0.42 $ 0.37   $ 2.99 $ 1.90 $ 1.16
Weighted average shares - basic 80,317 80,866 80,809 80,644 80,268 79,864 79,394 78,906   80,658 79,609 78,842
Net income per share - diluted $ 0.84 $ 0.77 $ 0.68 $ 0.68 $ 0.59 $ 0.50 $ 0.41 $ 0.36   $ 2.96 $ 1.86 $ 1.14
Weighted average shares - diluted 80,766 81,497 81,622 81,648 81,253 81,031 80,737 80,333   81,482 81,049 80,073

Consolidated Statements Of Shareholders' Equity And Comprehensive Income
v4.2.117.0
Consolidated Statements Of Shareholders' Equity And Comprehensive Income (USD $)
In Thousands, except Share data
Common Stock [Member]
Accumulated Other Comprehensive Income/(Loss) [Member]
Retained Earnings [Member]
Total Shareholders' Equity [Member]
Total
Balance at Sep. 30, 2008 $ 477,299 $ (6,076) $ 247,036 $ 718,259  
Balance, shares at Sep. 30, 2008 79,094,000        
Exercise of employee stock options 7,243     7,243  
Exercise of employee stock options, shares 498,000        
Issuance of stock under employee stock purchase plan 11,574     11,574  
Issuance of stock under employee stock purchase plan, shares 561,000        
Issuance of restricted stock, shares 1,516,000        
Repurchase of common stock (87,436)     (87,436)  
Repurchase of common stock, shares (3,344,000)        
Tax benefit (loss) from employee stock transactions (1,958)     (1,958)  
Stock-based compensation 56,064     56,064  
Net income     91,535   91,535
Foreign currency translation adjustment   387      
Unrealized gain (loss) on securities, net of tax   3,352      
Comprehensive income       95,274  
Balance at Sep. 30, 2009 462,786 (2,337) 338,571 799,020  
Balance, shares at Sep. 30, 2009 78,325,000        
Exercise of employee stock options 17,618     17,618  
Exercise of employee stock options, shares 911,000        
Issuance of stock under employee stock purchase plan 13,936     13,936  
Issuance of stock under employee stock purchase plan, shares 458,000        
Issuance of restricted stock, shares 1,849,000        
Repurchase of common stock (75,000)     (75,000)  
Repurchase of common stock, shares (1,188,000)        
Tax benefit (loss) from employee stock transactions 27,102     27,102  
Stock-based compensation 70,773     70,773  
Net income     151,153   151,153
Foreign currency translation adjustment   (771)      
Unrealized gain (loss) on securities, net of tax   (133)      
Comprehensive income       150,249  
Balance at Sep. 30, 2010 517,215 (3,241) 489,724 1,003,698 1,003,698
Balance, shares at Sep. 30, 2010 80,355,000       80,355,000
Exercise of employee stock options 2,293     2,293  
Exercise of employee stock options, shares 150,000       150,416
Issuance of stock under employee stock purchase plan 18,932     18,932  
Issuance of stock under employee stock purchase plan, shares 257,000        
Issuance of restricted stock, shares 1,370,000        
Repurchase of common stock (271,526)     (271,526)  
Repurchase of common stock, shares (2,987,000)        
Tax benefit (loss) from employee stock transactions 24,076     24,076  
Stock-based compensation 89,747     89,747  
Net income     241,397   241,397
Foreign currency translation adjustment   (2,366)      
Unrealized gain (loss) on securities, net of tax   (815)      
Comprehensive income       238,216  
Balance at Sep. 30, 2011 $ 380,737 $ (6,422) $ 731,121 $ 1,105,436 $ 1,105,436
Balance, shares at Sep. 30, 2011 79,145,000       79,145,000

Consolidated Statements Of Cash Flows
v4.2.117.0
Consolidated Statements Of Cash Flows (USD $)
In Thousands
12 Months Ended
Sep. 30, 2011
Sep. 30, 2010
Sep. 30, 2009
Operating activities      
Net income $ 241,397 $ 151,153 $ 91,535
Adjustments to reconcile net income to net cash provided by operating activities:      
Realized gain on disposition of assets and investments (163) (125) (9)
Stock-based compensation 89,747 70,773 56,064
Provisions for doubtful accounts and sales returns 982 1,206 2,638
Depreciation and amortization 20,887 23,833 26,407
Deferred income taxes 4,487 8,243 (6,057)
Gain on auction rate securities put option   (1,491) (3,901)
Loss on trading auction rate securities   1,491 3,901
Changes in operating assets and liabilities, net of amounts acquired:      
Accounts receivable (54,526) (6,365) (12,555)
Inventories 1,666 (4,996) (3,671)
Other current assets 8,000 (17,064) (523)
Other assets 81 (1,466) (226)
Accounts payable and accrued liabilities 20,476 12,157 10,248
Deferred revenue 83,904 76,263 38,130
Net cash provided by operating activities 416,938 313,612 201,981
Investing activities      
Purchases of investments (979,597) (877,003) (414,857)
Maturities of investments 812,042 603,825 315,110
Sales of investments 63,977 45,050 13,000
Decrease in restricted cash 19 2,530 13
Acquisition of intangible assets (5,715)   (706)
Purchases of property and equipment (30,445) (12,625) (11,669)
Net cash used in investing activities (139,719) (238,223) (99,109)
Financing activities      
Excess tax benefit (loss) from stock-based compensation 23,623 26,532 (1,958)
Proceeds from the exercise of stock options and purchases of stock under employee stock purchase plan 21,239 31,670 18,688
Repurchase of common stock (271,526) (75,000) (87,436)
Net cash used in financing activities (226,664) (16,798) (70,706)
Net increase in cash and cash equivalents 50,555 58,591 32,166
Effect of exchange rate changes on cash and cash equivalents (2,525) (674) 368
Cash and cash equivalents, beginning of year 168,754 110,837 78,303
Cash and cash equivalents, end of year 216,784 168,754 110,837
Supplemental Information      
Cash paid for taxes $ 84,753 $ 67,120 $ 48,586

Summary Of Significant Accounting Policies
v4.2.117.0
Summary Of Significant Accounting Policies
12 Months Ended
Sep. 30, 2011
Summary Of Significant Accounting Policies [Abstract]  
Summary Of Significant Accounting Policies

1.  Summary of Significant Accounting Policies

The Company

F5 Networks, Inc. (the "Company") provides products and services to help companies manage their Internet Protocol (IP) traffic and file storage infrastructure efficiently and securely. The Company's application delivery networking products improve the performance, availability and security of applications on Internet-based networks. Internet traffic between network-based applications and clients passes through these devices where the content is inspected to ensure that it is safe and modified as necessary to ensure that it is delivered securely and in a way that optimizes the performance of both the network and the applications. The Company's storage virtualization products simplify and reduce the cost of managing files and file storage devices, and ensure fast, secure, easy access to files for users and applications. The Company also offers a broad range of services that include consulting, training, maintenance and other technical support services.

Accounting Principles

The Company's consolidated financial statements and accompanying notes are prepared on the accrual basis of accounting in accordance with generally accepted accounting principles in the United States of America (GAAP).

Principles of Consolidation

The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.

Cash and Cash Equivalents

The Company considers all highly liquid investments with original maturities of three months or less to be cash equivalents. The Company invests its cash and cash equivalents in deposits with four major financial institutions, which, at times, exceed federally insured limits. The Company has not experienced any losses on its cash and cash equivalents.

 

 

Recent Accounting Pronouncements

In May 2011, the FASB issued ASU 2011-04, Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in U.S. GAAP and IFRS (ASU 2011-04), which amends current fair value measurement and disclosure guidance to converge with International Financial Reporting Standards (IFRS) and provides increased transparency around valuation inputs and investment categorization. The amendments in this standard are effective for fiscal years, and interim periods within those years beginning after December 15, 2011. The Company will adopt ASU 2011-04 in the first quarter of fiscal 2013 and does not expect the adoption of this standard to have an impact on its consolidated financial statements.

In June 2011, the FASB issued ASU 2011-05, Comprehensive Income, Presentation of Comprehensive Income (ASU 2011-05), which eliminates the option of presenting other comprehensive income as part of the statement of changes in stockholders' equity and instead requires the entity to present other comprehensive income as either a single statement of comprehensive income combined with net income or as two separate but continuous statements. The amendments in this standard are to be applied retrospectively and are effective for fiscal years, and interim periods within those years beginning after December 15, 2011. The Company will adopt ASU 2011-05 in the first quarter of fiscal 2013 and does not expect the adoption of this standard to have an impact on its consolidated financial statements.

In September 2011, the FASB issued ASU 2011-08, Intangibles – Goodwill and Other, Testing Goodwill for Impairment (ASU 2011-08), which simplifies how an entity tests goodwill for impairment by allowing the entity to first assess qualitative factors to determine whether it is necessary to perform the two-step quantitative goodwill impairment test. If an entity determines, as a result of its qualitative assessment, that it is more-likely-than-not that the fair value of a reporting unit is less than its carrying amount, the quantitative impairment test is required. Otherwise, no further testing is required. ASU 2011-08 is effective for annual and interim goodwill impairment tests performed for fiscal years beginning after December 15, 2011, with early adoption permitted. The Company is likely to early adopt this standard for the goodwill impairment test to be performed in fiscal 2012. This standard will impact how the Company assesses goodwill for impairment but will not change the measurement or recognition of a potential goodwill impairment charge.


Summary Of Significant Accounting Policies (Policy)
v4.2.117.0
Summary Of Significant Accounting Policies (Policy)
12 Months Ended
Sep. 30, 2011
Summary Of Significant Accounting Policies [Abstract]  
Principles Of Consolidation

Principles of Consolidation

The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.

Reclassifications
Use Of Estimates
Cash And Cash Equivalents

Cash and Cash Equivalents

The Company considers all highly liquid investments with original maturities of three months or less to be cash equivalents. The Company invests its cash and cash equivalents in deposits with four major financial institutions, which, at times, exceed federally insured limits. The Company has not experienced any losses on its cash and cash equivalents.

Investments
Concentration Of Credit Risk
Fair Value Of Financial Instruments
Inventories
Property And Equipment
Goodwill
Other Assets
Impairment Of Long-Lived Assets
Revenue Recognition
Shipping And Handling
Guarantees And Product Warranties
Research And Development
Advertising
Income Taxes
Foreign Currency
Segments
Stock-Based Compensation
Earnings Per Share

Summary Of Significant Accounting Policies (Tables)
v4.2.117.0
Summary Of Significant Accounting Policies (Tables)
12 Months Ended
Sep. 30, 2011
Summary Of Significant Accounting Policies [Abstract]  
Schedule Of Inventories
                 
     Years Ended
September 30,
 
     2011      2010  

Finished goods

   $ 12,917       $ 14,949   

Raw materials

     4,232         3,866   
    

 

 

    

 

 

 
     $ 17,149       $ 18,815   
    

 

 

    

 

 

 
Schedule Of Property And Equipment
                 
     Years Ended
September 30,
 
     2011     2010  

Computer equipment

   $ 77,899      $ 59,557   

Office furniture and equipment

     11,243        9,793   

Leasehold improvements

     41,344        36,462   
    

 

 

   

 

 

 
       130,486        105,812   

Accumulated depreciation and amortization

     (82,488     (71,655
    

 

 

   

 

 

 
     $ 47,998      $ 34,157   
    

 

 

   

 

 

 
Schedule Of Assumptions In Determining The Fair Value Of Shares Issued Under The Employee Stock Purchase Plan
                         
     Employee Stock Purchase Plan
Years Ended September 30,
 
     2011     2010     2009  

Risk-free interest rate

     0.10     0.25     0.31

Expected dividend

     —          —          —     

Expected term

     0.5 years        0.5 years        0.5 years   

Expected volatility

     53.87     41.04     47.00
Schedule Of Computation Of Basic And Diluted Net Income Per Share
                         
     Years Ended September 30,  
     2011      2010      2009  

Numerator

                          

Net income

   $ 241,397       $ 151,153       $ 91,535   

Denominator

                          

Weighted average shares outstanding — basic

     80,658         79,609         78,842   

Dilutive effect of common shares from stock options and restricted stock units

     824         1,440         1,231   
    

 

 

    

 

 

    

 

 

 

Weighted average shares outstanding — diluted

     81,482         81,049         80,073   
    

 

 

    

 

 

    

 

 

 

Basic net income per share

   $ 2.99       $ 1.90       $ 1.16   
    

 

 

    

 

 

    

 

 

 

Diluted net income per share

   $ 2.96       $ 1.86       $ 1.14   
    

 

 

    

 

 

    

 

 

 

Summary Of Significant Accounting Policies (Narrative) (Details)
v4.2.117.0
Summary Of Significant Accounting Policies (Narrative) (Details) (USD $)
1 Months Ended 12 Months Ended 12 Months Ended 1 Months Ended 1 Months Ended 12 Months Ended
Aug. 31, 2011
Aug. 31, 2010
Aug. 31, 2009
Sep. 30, 2011
years
Sep. 30, 2010
Sep. 30, 2009
Sep. 30, 2007
Acopia [Member]
Acquired Technology [Member]
Sep. 30, 2006
Swan Labs [Member]
Acquired Technology [Member]
Sep. 30, 2011
Acquired Technology [Member]
Sep. 30, 2010
Acquired Technology [Member]
Sep. 30, 2009
Acquired Technology [Member]
Sep. 30, 2011
Customer Relationships, Patents And Trademarks [Member]
Sep. 30, 2010
Customer Relationships, Patents And Trademarks [Member]
Sep. 30, 2009
Customer Relationships, Patents And Trademarks [Member]
Sep. 30, 2011
Avnet Technology Solutions [Member]
Sep. 30, 2010
Avnet Technology Solutions [Member]
Sep. 30, 2011
Ingram Micro, Inc. [Member]
Sep. 30, 2010
Ingram Micro, Inc. [Member]
Sep. 30, 2010
Tech Data [Member]
Sep. 30, 2011
Minimum [Member]
Sep. 30, 2011
Maximum [Member]
Sep. 30, 2011
Restricted Stock Unit [Member]
Nov. 30, 2011
Annual Equity Program [Member]
Aug. 31, 2011
Annual Equity Program [Member]
Aug. 31, 2010
Annual Equity Program [Member]
Sep. 30, 2011
Annual Equity Program [Member]
Aug. 31, 2010
Retention Awards Program [Member]
Sep. 30, 2011
Executive Officers And Board Of Directors [Member]
Sep. 30, 2011
Other Employees [Member]
Schedule Of Summary Of Significant Accounting Policies [Line Items]                                                          
Accounts receivable from major customers, percentage                             15.00% 13.20% 14.50% 13.20% 11.80%                    
Estimated useful lives of the assets, minimum, in years       2                                                  
Estimated useful lives of the assets, maximum, in years       5                                                  
Depreciation and amortization       $ 16,600,000 $ 17,800,000 $ 18,400,000                                              
Capitalized software development costs       0 0 0                                              
Acquired and developed technology and customer relationship assets estimated useful lives       5                                                  
Acquired technology in connection with the acquisitions             15,000,000 8,000,000                                          
Amortization expense related to acquired technology                 3,100,000 4,600,000 5,300,000                                    
Amortization expense of all other intangible assets                       0 0 0                              
Domestic accounts receivable terms of payment                                       30 45                
International accounts receivable terms of payment                                       30 120                
Range of VSOE to median sales price       15.00%                                                  
Advertising costs       2,200,000 2,100,000 1,300,000                                              
Stock-based compensation       89,747,000 70,773,000 56,064,000                                              
Unrecognized stock-based compensation cost       $ 105,500,000                                                  
Unrecognized stock-based compensation cost, period for recognition, years       2                                                  
Rate for grant awarded                                                       3.00% 9.00%
Stock options granted       0 0 0                                              
Approved RSUs to employees and executive officers by compensation committee       1,718,042                                           833,739      
Approved RSUs to employees and executive officers pursuant to the Company's annual equity awards program     420,000                                     908,757 82,968 170,390 181,334   83,000    
Annual equity awards program vesting period     two years two-year two-year two-year                                   three years three years        
RSU vesting date for annual equity and retention awards programs   August 1, 2013 August 1, 2011                                                    
Percentage of quarterly performance stock grant based on achieving quarterly revenue goal 50.00% 50.00% 50.00%                                                    
Percentage of quarterly performance stock grant based on achieving EBITDA goal 50.00% 50.00% 50.00%                                                    
Percentage of quarterly revenue goal to be achieved for performance stock grant 80.00% 80.00% 80.00%                                                    
Percentage of achievement threshold to which the goals are entitled 80.00% 80.00% 80.00%                                                    
Percentage of over-achievement threshold to which the goals are entitled 100.00% 100.00% 100.00%                                                    
Percentage of annual equity awards RSU grant subject to performance based vesting 33.33% 33.33%                                                      
Percentage of annual equity awards RSU grant subject to performance based vesting in each period 16.66% 16.66%                                                      
Percentage of the aggregate number of RSUs granted that vest in equal quarterly increments 50.00% 50.00% 50.00%                                                    
Annual equity awards RSU grant subject to achieving specified quarterly revenue and EBITDA goal     twenty-five percent                                                    

Summary Of Significant Accounting Policies (Schedule Of Inventories) (Details)
v4.2.117.0
Summary Of Significant Accounting Policies (Schedule Of Inventories) (Details) (USD $)
In Thousands
Sep. 30, 2011
Sep. 30, 2010
Summary Of Significant Accounting Policies [Abstract]    
Finished goods $ 12,917 $ 14,949
Raw materials 4,232 3,866
Inventories, Total $ 17,149 $ 18,815

Summary Of Significant Accounting Policies (Schedule Of Property And Equipment) (Details)
v4.2.117.0
Summary Of Significant Accounting Policies (Schedule Of Property And Equipment) (Details) (USD $)
In Thousands
Sep. 30, 2011
Sep. 30, 2010
Summary Of Significant Accounting Policies [Abstract]    
Computer equipment $ 77,899 $ 59,557
Office furniture and equipment 11,243 9,793
Leasehold improvements 41,344 36,462
Property and equipment, gross 130,486 105,812
Accumulated depreciation and amortization (82,488) (71,655)
Property and equipment, net $ 47,998 $ 34,157

Summary Of Significant Accounting Policies (Schedule Of Assumptions In Determining The Fair Value Of Shares Issued Under The Employee Stock Purchase Plan) (Details)
v4.2.117.0
Summary Of Significant Accounting Policies (Schedule Of Assumptions In Determining The Fair Value Of Shares Issued Under The Employee Stock Purchase Plan) (Details)
12 Months Ended
Sep. 30, 2011
years
Sep. 30, 2010
years
Sep. 30, 2009
years
Summary Of Significant Accounting Policies [Abstract]      
Risk-free interest rate 0.10% 0.25% 0.31%
Expected term 0.5 0.5 0.5
Expected volatility 53.87% 41.04% 47.00%

Summary Of Significant Accounting Policies (Schedule Of Computation Of Basic And Diluted Net Income Per Share) (Details)
v4.2.117.0
Summary Of Significant Accounting Policies (Schedule Of Computation Of Basic And Diluted Net Income Per Share) (Details) (USD $)
In Thousands, except Per Share data
3 Months Ended 12 Months Ended
Sep. 30, 2011
Jun. 30, 2011
Mar. 31, 2011
Dec. 31, 2010
Sep. 30, 2010
Jun. 30, 2010
Mar. 31, 2010
Dec. 31, 2009
Sep. 30, 2011
Sep. 30, 2010
Sep. 30, 2009
Summary Of Significant Accounting Policies [Abstract]                      
Net income $ 67,610 $ 62,549 $ 55,575 $ 55,663 $ 48,235 $ 40,495 $ 33,144 $ 29,279 $ 241,397 $ 151,153 $ 91,535
Weighted average shares outstanding - basic 80,317 80,866 80,809 80,644 80,268 79,864 79,394 78,906 80,658 79,609 78,842
Dilutive effect of common shares from stock options and restricted stock units                 824 1,440 1,231
Weighted average shares outstanding - diluted 80,766 81,497 81,622 81,648 81,253 81,031 80,737 80,333 81,482 81,049 80,073
Basic net income per share $ 0.84 $ 0.77 $ 0.69 $ 0.69 $ 0.60 $ 0.51 $ 0.42 $ 0.37 $ 2.99 $ 1.90 $ 1.16
Diluted net income per share $ 0.84 $ 0.77 $ 0.68 $ 0.68 $ 0.59 $ 0.50 $ 0.41 $ 0.36 $ 2.96 $ 1.86 $ 1.14