Stock-Based Compensation - Summary of Stock Option Activity (Detail)	3 Months Ended
	Mar. 31, 2018 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of Shares, Beginning Balance | shares	109,808
Number of Shares, Exercised | shares	(22,245)
Number of Shares, Ending Balance | shares	87,563
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	$ 16.44
Weighted Average Exercise Price, Exercised (in $ per share) | $ / shares	31.38
Weighted Average Exercise Price, Ending Balance (in $ per share) | $ / shares	$ 12.64