NET INCOME PER SHARE (Calculation of Net Income per Common Share (Detail) - USD ($) $ / shares in Units, $ 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	$ 13,316	$ 13,474	$ 10,647	$ 10,813	$ 12,802	$ 10,995	$ 10,333	$ 11,225	$ 48,250	$ 45,355	$ 38,200
Basic:
Basic weighted average EPS shares									24,120,000	24,609,000	25,047,000
Basic net income per share	$ 0.55	$ 0.56	$ 0.45	$ 0.45	$ 0.53	$ 0.45	$ 0.42	$ 0.45	$ 2	$ 1.84	$ 1.53
Diluted:
Basic weighted average EPS shares									24,120,000	24,609,000	25,047,000
Dilutive common stock equivalents									29,000	89,000	92,000
Dilutive EPS shares									24,149,000	24,698,000	25,139,000
Diluted net income per share	$ 0.55	$ 0.56	$ 0.44	$ 0.45	$ 0.52	$ 0.45	$ 0.42	$ 0.45	$ 2	$ 1.84	$ 1.52
Anti-dilutive shares									3,000	7,000	56,000