CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Net income	$ 23,426	$ 29,156	$ 55,441	$ 51,886
Other Comprehensive Income [Abstract]
Unrealized losses on available-for-sale securities (net of taxes of $43 and $83 for the quarter and year-to-date 2012 and $37 and $178 for the quarter and year-to-date 2011, respectively)	(947)	(1,545)	(584)	(791)
Foreign currency translation adjustments	(16,510)	4,671	(1,693)	20,398
Other comprehensive (loss) income	(17,457)	3,126	(2,277)	19,607
Comprehensive income	$ 5,969	$ 32,282	$ 53,164	$ 71,493