Stock-Based Compensation - Option Activity (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) $ / shares shares
Number of Shares
Options, Outstanding Beginning Balance (in shares) | shares	611,977
Options, Granted (in shares) | shares	73,000
Options, Exercised (in shares) | shares	(167,523)
Option, Expired (in shares) | shares	(13,875)
Options, Forfeited (in shares) | shares	(20,088)
Options, Outstanding Ending Balance (in shares) | shares	483,491
Options, Exercisable at end of period (in shares) | shares	251,891
Weighted-Average Exercise Price Per Share
Options, Beginning Balance (in dollars per share) | $ / shares	$ 19.02
Options, Granted (in dollars per share) | $ / shares	25.51
Options, Exercised (in dollars per share) | $ / shares	18.42
Options, Expired, (in dollars per share) | $ / shares	18.58
Options, Forfeited (in dollars per share) | $ / shares	22.29
Options, Ending Balance (in dollars per share) | $ / shares	20.08
Options, Exercisable at end of period (in dollars per share) | $ / shares	$ 18.80
Options, Outstanding at end of period, Weighted Average Remaining Contractual Life (Years)	4 years 1 month
Options, Exercisable at end of period, Weighted Average Remaining Contractual Life (Years)	3 years 5 months
Options, Outstanding at end of period, Aggregate Intrinsic Value | $	$ 689
Options, Exercisable at end of period, Aggregate Intrinsic Value | $	$ 417