Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Statement [Abstract]
Net sales	$ 80,461	$ 37,806	$ 153,290	$ 101,830
Cost of sales	66,725	34,903	126,836	88,161
Gross margin	13,736	2,903	26,454	13,669
Selling, general and administrative expense	7,563	4,109	14,935	10,614
Operating income (loss)	6,173	(1,206)	11,519	3,055
Other income and expense
Interest expense	584	1,197	1,163	2,371
Net periodic post-retirement benefit	(40)	(20)	(80)	(40)
Total other expense	544	1,177	1,083	2,331
Income (loss) before taxes	5,629	(2,383)	10,436	724
Income tax expense (benefit)	1,543	(111)	2,894	(4,965)
Net Income (Loss) Attributable to Parent, Total	$ 4,086	$ (2,272)	$ 7,542	$ 5,689
Net income (loss) per common share:
Basic (in USD per share)	$ 0.48	$ (0.29)	$ 0.89	$ 0.69
Diluted (in USD per share)	$ 0.48	$ (0.29)	$ 0.89	$ 0.69