Stock Incentive Plans - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding and exercisable as of beginning of period (in shares)	57	180	247
Exercised (in shares)	(32)	(105)	(67)
Forfeited/Cancelled (in shares)		(18)
Outstanding and exercisable as of end of period (in shares)	25	57	180
Weighted Average Exercise Price Per Share
Outstanding and exercisable as of beginning of period (in dollars per share)	$ 11.69	$ 11.57	$ 10.87
Exercised (in dollars per share)	11.78	11.61	8.98
Forfeited/Cancelled (in dollars per share)		11.00
Outstanding and exercisable as of end of period (in dollars per share)	$ 11.58	$ 11.69	$ 11.57
Total Intrinsic Value of Options Exercised
Exercised, total intrinsic value of options exercised	$ 359	$ 1,029	$ 573
Incentive Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding and exercisable as of beginning of period (in shares)	22	97	154
Exercised (in shares)	(22)	(57)	(57)
Forfeited/Cancelled (in shares)		(18)
Outstanding and exercisable as of end of period (in shares)	0	22	97
2006 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding and exercisable as of beginning of period (in shares)	35	83	93
Exercised (in shares)	(10)	(48)	(10)
Forfeited/Cancelled (in shares)		0
Outstanding and exercisable as of end of period (in shares)	25	35	83