XML 44 R29.htm IDEA: XBRL DOCUMENT v3.8.0.1
Description Of Business And Summary Of Significant Accounting Policies (Narrative) (Details) - USD ($)
$ in Thousands
 1 Months Ended 12 Months Ended
Aug. 31, 2007
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Jan. 01, 2017
Aug. 15, 2007
Description Of Business And Summary Of Significant Accounting Policies [Line Items]            
Capitalized Computer Software, Additions   $ 17,700 $ 18,000      
Convertible debenture, interest rate           3.25%
Convertible debenture, maturity date Aug. 15, 2037          
Net remeasurement gain (loss) on foreign currency translation   1,000 1,000      
Gains (losses) on foreign currency forward contracts   1,000 1,000      
Advertising expenses   27,400 17,200 $ 16,000    
Derivative, Notional Amount   29,700        
Deferred Tax Liabilities, Net, Noncurrent   444,108 371,433      
Deferred Tax Liabilities, Other   3,116 2,614      
Deferred Tax Asset for previously unrecognized excess tax benefits   35,400        
excess tax benefit related to stock based compensation     $ 25,100 $ 18,500    
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification   $ 27,300        
Building Improvements [Member]            
Description Of Business And Summary Of Significant Accounting Policies [Line Items]            
Estimated useful life of property and equipment (years)   10 years        
Maximum [Member]            
Description Of Business And Summary Of Significant Accounting Policies [Line Items]            
RegistrationTerm   10 years        
Average Service Term   2 years        
Maximum [Member] | Buildings [Member]            
Description Of Business And Summary Of Significant Accounting Policies [Line Items]            
Estimated useful life of property and equipment (years)   47 years        
Maximum [Member] | Computer Equipment, Purchased Software, Office Equipment, And Furniture And Fixtures [Member]            
Description Of Business And Summary Of Significant Accounting Policies [Line Items]            
Estimated useful life of property and equipment (years)   5 years        
Minimum [Member]            
Description Of Business And Summary Of Significant Accounting Policies [Line Items]            
RegistrationTerm   1 year        
Average Service Term   1 year        
Minimum [Member] | Buildings [Member]            
Description Of Business And Summary Of Significant Accounting Policies [Line Items]            
Estimated useful life of property and equipment (years)   35 years        
Minimum [Member] | Computer Equipment, Purchased Software, Office Equipment, And Furniture And Fixtures [Member]            
Description Of Business And Summary Of Significant Accounting Policies [Line Items]            
Estimated useful life of property and equipment (years)   3 years        
Deferred Tax Asset [Domain]            
Description Of Business And Summary Of Significant Accounting Policies [Line Items]            
Cumulative Effect of New Accounting Principle in Period of Adoption         $ 11,000  
Additional Paid-in Capital [Member]            
Description Of Business And Summary Of Significant Accounting Policies [Line Items]            
Cumulative Effect of New Accounting Principle in Period of Adoption         2,544  
Retained Earnings [Member]            
Description Of Business And Summary Of Significant Accounting Policies [Line Items]            
Cumulative Effect of New Accounting Principle in Period of Adoption         32,916  
Long-term deferred tax liability [member]            
Description Of Business And Summary Of Significant Accounting Policies [Line Items]            
Cumulative Effect of New Accounting Principle in Period of Adoption         $ 24,400