Earnings and Dividends per Share - Number of Shares Outstanding for Calculation of Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Basic net income (loss) and earnings (loss) per share, Numerator (Income)	$ 5,804	$ (4,825)	$ 12,954	$ (2,523)
Common stock equivalents arising from stock options, restricted stock awards, and employee stock purchase plan, Numerator (Income)	0	0	0	0
Diluted earnings (loss) and earnings (loss) per share, Numerator (Income)	$ 5,804	$ (4,825)	$ 12,954	$ (2,523)
Basic net income (loss) and earnings (loss) per share, Denominator (Shares)	33,983,708	28,617,589	33,952,768	27,066,072
Common stock equivalents arising from stock options, restricted stock awards, and employee stock purchase plan, Denominator (Shares)	371,000		258,000
Diluted earnings (loss) and earnings (loss) per share, Denominator (Shares)	34,354,687	28,617,589	34,211,067	27,066,072
Basic net income (loss) and earning (loss) per share, Per Share Amount	$ 0.17	$ (0.17)	$ 0.38	$ (0.09)
Diluted earning (loss) and earning (loss) per share, Per Share Amount	$ 0.17	$ (0.17)	$ 0.38	$ (0.09)