Consolidated Statements Of Comprehensive Income (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Consolidated Statements Of Comprehensive Income [Abstract]
Net income	$ 174,643,000	$ 101,778,000	$ 47,104,000
Other comprehensive income (loss):
Unrealized gain (loss) on hedging transactions, net of income taxes	6,209,000	(949,000)	19,000
Unrealized holding gains (losses) on investments, net of income taxes	(385,000)	(406,000)	737,000
Foreign currency translation adjustment	(688,000)	67,000	3,972,000
Comprehensive income	$ 179,779,000	$ 100,490,000	$ 51,832,000