Consolidated Statements Of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Consolidated Statements Of Comprehensive Income [Abstract]
Net income	$ 18,115	$ 2,878	$ 56,607	$ 51,959	$ 79,758
Other comprehensive income (loss):
Foreign currency translation adjustments			993	(6,903)	(2,318)
Unrealized gain on investments, net of tax			1,476	526	536
Other			445	(111)	(187)
Comprehensive income			59,521	45,471	77,789
Foreign currency translation losses	(8,681)	(9,674)	(8,681)	(9,674)
Unrealized loss on investments, net of tax	(1,851)	(3,327)	(1,851)	(3,327)
Other	(4)	(449)	(4)	(449)
Accumulated other comprehensive loss	$ (10,536)	$ (13,450)	$ (10,536)	$ (13,450)