(Loss) Income Per Common Share - Computations of Basic and Diluted (Loss) Income Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Earnings Per Share Reconciliation [Abstract]
Net (loss) income, as reported		$ (91,710)	$ 27,684
Participating earnings	[1]	(56)	(463)
Basic net (loss) income attributed to common shareholders		(91,766)	27,221
Reallocation of participating earnings	[1]	0	0
Diluted net (loss) income attributed to common shareholders		$ (91,766)	$ 27,221
Net (loss) income per common share:
Basic		$ (0.55)	$ 0.16
Diluted		$ (0.55)	$ 0.16

[1] Restricted Stock Awards represent participating securities because they participate in nonforfeitable dividends or distributions with common equity owners. Income allocable to participating securities represents the distributed and undistributed earnings attributable to the participating securities. Participating securities, however, do not participate in undistributed net losses.