Income Taxes - Reconciliation of Income Tax (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Tax expense at statutory rate, Amount	$ (18,299)	$ 99,062	$ 39,116
State income taxes, Amount	2,281	(2,894)	6,218
Tax-free disposition of investment, Amount	0	(145,524)	0
Uncertain tax positions, Amount	(15,451)	6,106	0
Sale of unconsolidated affiliate, Amount	0	(545)	40,411
Change in valuation allowances, Amount	3,016	(213)	366
Other, Amount	(3,643)	1,683	1,834
Total income tax expense (benefit)	$ (32,096)	$ (42,325)	$ 87,945
Tax expense at statutory rate, Percentage	35.00%	35.00%	35.00%
State income taxes, Percentage	(4.40%)	(1.00%)	5.60%
Tax-free disposition of investment, Percentage	0.00%	(51.40%)	0.00%
Uncertain tax positions, Percentage	29.60%	2.20%	0.00%
Sale of unconsolidated affiliate, Percentage	0.00%	(0.20%)	36.20%
Change in valuation allowances, Percentage	(5.80%)	(0.10%)	0.30%
Other, Percentage	7.00%	0.60%	1.60%
Total, Percentage	61.40%	(14.90%)	78.70%