Significant Components of the Provision for Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Current:
Federal	$ 57,429	$ 34,061	$ 23,712
State	4,288	3,303	2,080
Foreign	1,374	607	619
Total current	63,091	37,971	26,411
Deferred	4,223	2,662	573
Income taxes	$ 67,314	$ 40,633	$ 26,984