Earnings Per Share - Components of Numerator and Denominator for Computation 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, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Net income (loss) attributable to common shareholders - Basic									$ 7,967	$ 4,418	$ (31,783)
Interest on Convertible Notes									3,383
(Gain) loss on derivative liability									5,805	(9,901)	(16,671)
Net income (loss) attributable to common shareholders - Diluted									$ 5,545	$ 4,418	$ (31,783)
Weighted average common shares - Basic (shares)									32,132	31,514	31,190
Share-based awards (shares)									593	648	0
Convertible Notes (shares)									3,521	0	0
Weighted average common shares - Diluted (shares)									36,246	32,162	31,190
Net income (loss) per share attributable to common shareholders - Basic (usd per share)	$ (0.24)	$ 0.44	$ (0.54)	$ 0.60	$ (0.19)	$ 0.16	$ 0.08	$ 0.09	$ 0.25	$ 0.14	$ (1.02)
Net income (loss) per share attributable to common shareholders - Diluted (usd per share)	$ (0.24)	$ 0.22	$ (0.54)	$ 0.09	$ (0.19)	$ 0.16	$ 0.08	$ 0.05	$ 0.15	$ 0.14	$ (1.02)