Net (Loss)Income Per Share - Computations of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Weighted average shares outstanding, Basic:
Common stock, Basic									8,069	10,283	11,963
Stock options, unvested restricted stock and RSUs, Basic									0	0	0
Weighted average common and common equivalent shares outstanding, Basic									8,069	10,283	11,963
Net (loss) income applicable to common stock, Basic									$ (7,461)	$ 17,019	$ 92,912
Net (loss) income per common share, Basic	$ (0.59)	$ (0.43)	$ 0.36	$ (0.29)	$ 0.10	$ 0.34	$ 0.65	$ 0.51	$ (0.92)	$ 1.66	$ 7.77
Weighted average shares outstanding, Diluted:
Common stock, Diluted									8,069	10,283	11,963
Stock options, unvested restricted stock and RSUs, Diluted									0	1,182	997
Weighted average common and common equivalent shares outstanding, Diluted									8,069	11,465	12,960
Net (loss) income applicable to common stock, Diluted									$ (7,461)	$ 17,019	$ 92,912
Net (loss) income per common share, Diluted	$ (0.59)	$ (0.43)	$ 0.32	$ (0.29)	$ 0.09	$ 0.31	$ 0.58	$ 0.46	$ (0.92)	$ 1.48	$ 7.17