Income Taxes Charged to Earnings (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Current:
Federal	$ 59,121	$ 64,328	$ 228,683
Foreign	884	1,554	1,825
State	13,578	10,553	35,028
Total current taxes	73,583	76,435	265,536
Deferred:
Federal	(8,270)	(6,834)	(19,647)
Foreign	(146)	223	1,743
State	714	(3,510)	(382)
Total deferred taxes	(7,702)	(10,121)	(18,286)
Income tax expense	$ 65,881	$ 66,314	$ 247,250