CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME
Net sales	$ 571,710	$ 524,067	$ 474,927
Cost of sales	402,893	369,177	331,841
Gross profit	168,817	154,890	143,086
Selling, general, and administrative expense	71,288	69,958	60,877
Intangibles amortization	10,956	11,472	11,401
Income from operations	86,573	73,460	70,808
Interest expense, net	(16,782)	(16,943)	(18,336)
Litigation proceeds	200		1,275
Pension termination	(6,609)
Other expense, net	(765)	(758)	(832)
Income before taxes	62,617	55,759	52,915
Income tax expense (benefit)	13,451	11,854	(2,409)
Net income	$ 49,166	$ 43,905	$ 55,324
Earnings per share:
Basic earnings per common share attributable to common shareholders (in dollars per share)	$ 2.13	$ 1.91	$ 2.42
Earnings per common share assuming dilution attributable to common shareholders (in dollars per share)	2.11	1.89	2.40
Cash dividends declared per share (in dollars per share)	1.09	1.06	0.96
Cash dividends declared per share (in dollars per share)	$ 1.09	$ 1.06	$ 0.96