Earnings (Loss) Per Share - Schedule of Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Basic:
Net income (loss), basic									$ 18,826	$ 8,525	$ (206,735)
Net income (loss), shares, basic									19,999	17,479	16,096
Net income (loss), per share, basic	$ 1.81	$ 0.20	$ (0.95)	$ (0.13)	$ (0.75)	$ (0.95)	$ 0.66	$ 1.54	$ 0.94	$ 0.49	$ (12.84)
Weighted-average number of shares of common stock-diluted:
Restricted stock and performance unit awards									88	200
Diluted:
Net income (loss), diluted									$ 18,826	$ 8,525	$ (206,735)
Net income (loss), shares, diluted									20,087	17,679	16,096
Net income (loss), per share, diluted	$ 1.80	$ 0.20	$ (0.95)	$ (0.13)	$ (0.74)	$ (0.95)	$ 0.65	$ 1.52	$ 0.94	$ 0.48	$ (12.84)