Summarized Quarterly Financial Data (Unaudited) - Quarterly Operating Results (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Total Sales	$ 130,129	$ 133,143	$ 128,715	$ 114,523	$ 115,787	$ 114,092	$ 156,391	$ 143,791	$ 506,510	$ 530,061	$ 529,277
Gross Profit	53,517	58,962	53,472	51,600	47,209	46,331	65,015	60,612	217,551	219,167	203,565
Operating Income (Loss)	(3,324)	4,534	(6,039)	(4,944)	(14,070)	(20,288)	562	(6,167)	(9,773)	(39,963)	(45,422)
Net Income (Loss)	$ 6,114	$ 5,481	$ 752	$ (9,969)	$ (11,624)	$ (46,123)	$ 3,995	$ 770	$ 2,378	$ (52,982)	$ (19,342)
Earnings (loss) per common share - basic	$ 0.13	$ 0.11	$ 0.02	$ (0.21)	$ (0.25)	$ (0.96)	$ 0.08	$ 0.02	$ 0.05	$ (1.11)	$ (0.40)
Earnings (loss) per common share - diluted	$ 0.13	$ 0.11	$ 0.02	$ (0.21)	$ (0.25)	$ (0.96)	$ 0.08	$ 0.02	$ 0.05	$ (1.11)	$ (0.40)