Income Taxes - Components of Income Tax Expense (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Current:
Federal	$ 288,135	$ 260,222	$ 221,770
State	44,653	41,511	36,291
Foreign	23,352	26,294	16,217
Deferred	14,751	(2,337)	11,994
Income tax expense, total	$ 370,891	$ 325,690	$ 286,272