Earnings Per Share (Earnings Per Share) (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Numerator:
Net income	$ 14,133	$ 7,584	$ 26,355	$ 13,729
Denominator:
Weighted average shares of common stock outstanding	12,037	11,929	12,032	11,915
Effect of dilutive common stock equivalents	137	127	97	129
Weighted average shares of common stock outstanding	12,174	12,056	12,129	12,044
Basic earnings per share
Earnings per share	$ 1.17	$ 0.64	$ 2.19	$ 1.15
Diluted earnings per share
Earnings per share	$ 1.16	$ 0.63	$ 2.17	$ 1.14