Quarterly Financial Information (Unaudited) - Summary of Quarterly Financial Results (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
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 178,030	$ 180,041	$ 174,879	$ 165,487	$ 144,192	$ 155,725	$ 137,235	$ 129,700	$ 698,437	$ 566,852	$ 524,505
Gross profit	39,405	39,980	43,253	40,424	31,982	38,193	35,990	32,377	163,062	138,542	122,497
Net income	$ 13,848	$ 10,675	$ 13,125	$ 11,669	$ 4,420	$ 12,785	$ 10,813	$ 9,169	$ 49,317	$ 37,187	$ 46,259
Earnings per common share:
Basic (USD per share)	$ 0.81	$ 0.63	$ 0.77	$ 0.69	$ 0.26	$ 0.76	$ 0.64	$ 0.54	$ 2.89	$ 2.20	$ 2.76
Diluted (USD per share)	$ 0.80	$ 0.62	$ 0.76	$ 0.68	$ 0.26	$ 0.75	$ 0.63	$ 0.54	$ 2.85	$ 2.16	$ 2.71