Acquisition - Summary of Unaudited Pro Forma Results of Operations (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Combinations [Abstract]
Net sales	$ 122,212	$ 140,194	$ 157,941	$ 144,806	$ 95,322	$ 106,168	$ 146,450	$ 131,676	$ 565,153	$ 479,616	$ 440,804
Net income	$ 18,299	$ 20,098	$ 28,782	$ 27,949	$ 12,629	$ 7,787	$ 23,725	$ 23,706	$ 95,128	$ 67,847	$ 48,098
Basic earnings per common share	$ 0.62	$ 0.68	$ 0.98	$ 0.95	$ 0.43	$ 0.27	$ 0.81	$ 0.80	$ 3.24	$ 2.31	$ 1.53
Diluted earnings per common share	$ 0.62	$ 0.68	$ 0.97	$ 0.95	$ 0.43	$ 0.26	$ 0.80	$ 0.79	$ 3.22	$ 2.29	$ 1.52
Pro Forma Net sales									$ 597,288	$ 534,618
Pro Forma Net income									$ 96,608	$ 68,344
Pro Forma Basic earnings per common share									$ 3.29	$ 2.33
Pro Forma Diluted earnings per common share									$ 3.27	$ 2.31