Stock-Based Compensation - Summary of Stock Option Activity (Detail)	12 Months Ended
	Dec. 31, 2015 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of shares, Beginning Balance | shares	162,824
Number of shares, Granted | shares	0
Number of shares, Exercised | shares	(6,188)
Number of shares, Forfeited | shares	0
Number of shares, Ending Balance | shares	156,636
Number of shares, Vested and exercisable at end of period | shares	156,636
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted Average Exercise Price, Beginning Balance (in $ per share) | $ / shares	$ 18.79
Weighted Average Exercise Price, Granted (in $ per share) | $ / shares	0.00
Weighted Average Exercise Price, Exercised (in $ per share) | $ / shares	19.04
Weighted Average Exercise Price, Forfeited (in $ per share) | $ / shares	0.00
Weighted Average Exercise Price, Ending Balance (in $ per share) | $ / shares	18.78
Weighted Average Exercise Price, Vested and exercisable at end of period (in $ per share) | $ / shares	$ 18.78