Consolidated Statements of Comprehensive Income - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Statement of Comprehensive Income [Abstract]        
Net income $ 86,704 $ 79,425 $ 245,206 $ 250,276
Other comprehensive (loss) gain, net of tax:        
Foreign currency translation adjustments (3,053) (6,037) (5,704) (10,290)
Unrealized (loss) gain on investments:        
Unrealized (losses) gains during the period, net of income taxes of $94, $200, $(146) and $501 (160) (734) 190 (1,254)
Less: reclassification adjustment for losses (gains) realized in net income, net of income taxes of $(52), $(62), $(143) and $(49) 102 117 266 93
Unrealized (loss) gain on investments: (58) (617) 456 (1,161)
Total other comprehensive loss, net of tax (3,111) (6,654) (5,248) (11,451)
Comprehensive income $ 83,593 $ 72,771 $ 239,958 $ 238,825