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		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Earnings Per Share [Abstract]
Basic net income and earnings per share, Numerator (Income)	$ 4,050	$ 2,104	$ 7,150	$ 2,302
Common stock equivalents arising from stock options, restricted stock awards, and employee stock purchase plan, Numerator (Income)	0	0	0	0
Diluted earnings and earnings per share, Numerator (Income)	$ 4,050	$ 2,104	$ 7,150	$ 2,302
Basic net income and earnings per share, Denominator (Shares)	33,946,117	26,283,529	33,937,128	26,277,456
Common stock equivalents arising from stock options, restricted stock awards, and employee stock purchase plan, Denominator (Shares)	216,000	343,000	202,000	367,000
Diluted earnings and earnings per share, Denominator (Shares)	34,161,543	26,627,051	34,139,087	26,643,857
Basic net income and earning per share, Per Share Amount	$ 0.12	$ 0.08	$ 0.21	$ 0.09
Diluted earning and earning per share, Per Share Amount	$ 0.12	$ 0.08	$ 0.21	$ 0.09