Income Taxes - Provision (Benefit) for Income Taxes (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current
Federal	$ 0	$ 0	$ 0
State	600,000	600,000	600,000
Foreign	100,000	200,000	300,000
Gross	700,000	800,000	900,000
Deferred
Federal	15,000,000	(121,600,000)	4,800,000
State	2,700,000	(13,300,000)	400,000
Gross	17,700,000	(134,900,000)	5,200,000
Total provision (benefit) for taxes	$ 18,444,000	$ (134,137,000)	$ 6,112,000