Calculation of Net Income per Common Share (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Net income	$ 10,928	$ 10,558
Basic:
Basic weighted average EPS shares	24,999	24,911
Basic net income per share	$ 0.44	$ 0.42
Diluted:
Basic weighted average EPS shares	24,999	24,911
Dilutive common stock equivalents	125	92
Dilutive EPS shares	25,124	25,003
Diluted net income per share	$ 0.43	$ 0.42
Anti-dilutive shares	47	242