Income Taxes (Schedule of Components of Provision for Income Taxes) (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Disclosure [Abstract]
Current federal	$ 48,700,000	$ 21,900,000	$ 2,700,000
Current foreign	300,000	100,000	0
Current state and local	12,400,000	1,300,000	3,300,000
Total current income tax expense	61,400,000	23,300,000	6,000,000
Deferred federal	15,200,000	35,000,000	40,800,000
Deferred foreign	1,100,000	(1,700,000)	0
Deferred state and local, net of valuation provisions	(1,600,000)	5,200,000	1,100,000
Total deferred income tax expense	14,700,000	38,500,000	41,900,000
Provision for income taxes	$ 76,080,000	$ 61,824,000	$ 47,942,000