Income Taxes - Components of Income Tax Expense (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Federal - Current	$ 475	$ 0	$ 0
State - Current	0	7	0
Total current income tax expense	475	7	0
Federal - Deferred	122,853	82,841	42,809
State - Deferred	11,730	9,638	3,980
Total deferred income tax expense	134,583	92,479	46,789
Total income tax expense	$ 135,058	$ 92,486	$ 46,789

Amount of current federal tax expense (benefit) pertaining to income (loss) from continuing operations.

Amount of current income tax expense (benefit) pertaining to taxable income (loss) from continuing operations.

Amount of current state and local tax expense (benefit) pertaining to income (loss) from continuing operations.

Amount of deferred federal income tax expense (benefit) pertaining to income (loss) from continuing operations.

Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations.

Amount of deferred state and local tax expense (benefit) pertaining to income (loss) from continuing operations.