Schedule Of Components Of Income Tax Expense and Benefit (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Components Of Income Tax Expense Benefit [Line Items]
Current, Federal	$ 254,021	$ 165,409	$ 105,077
Current, Foreign	9,084	300	2,555
Current, State	39,076	22,901	16,547
Current, Total	302,181	188,610	124,179
Deferred, Federal and foreign	(21,408)	53,056	26,419
Deferred, State	(6,157)	5,800	1,704
Deferred, Total	(27,565)	58,856	28,123
Provision for income taxes	$ 274,616	$ 247,466	$ 152,302