Components of Income Tax (Benefit) Expense (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Expenses [Line Items]
Current income tax (benefit) expense, Federal		$ 13,674	$ 75,867	$ 70,379
Current income tax (benefit) expense, State		2,368	5,885	6,466
Current income tax (benefit) expense, Total		16,042	81,752	76,845
Deferred income tax (benefit) expense, Federal		(144,771)	8,576	17,167
Deferred income tax (benefit) expense, State		(6,266)	(2,815)	2,154
Deferred income tax (benefit) expense, Total	137,700	(151,037)	5,761	19,321
Income tax (benefit) expense		$ (134,995)	$ 87,513	$ 96,166

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.