Significant Components of Provision For Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Current:
Federal	$ 37,596	$ 57,429	$ 34,061
State	2,268	4,288	3,303
Foreign	1,581	1,374	607
Total current	41,445	63,091	37,971
Deferred	11,212	4,223	2,662
Income taxes	$ 52,657	$ 67,314	$ 40,633