Consolidated Statements of Income - 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	$ 143,876	$ 125,596	$ 259,664	$ 263,079
Cost of sales	101,769	87,465	184,400	182,001
Gross profit	42,107	38,131	75,264	81,078
Selling, general and administrative expenses	16,895	15,939	31,591	31,153
Gain on disposal of assets	0	0	0	(62)
Income from operations	25,212	22,192	43,673	49,987
Interest (expense) income, net	(4)	19	(1)	80
Other income (expense), net	39	32	56	5
Income before taxes	25,247	22,243	43,728	50,072
Income tax provision	4,632	4,439	6,737	10,415
Net income	$ 20,615	$ 17,804	$ 36,991	$ 39,657
Earnings per share:
Basic (usd per share)	$ 0.39	$ 0.34	$ 0.71	$ 0.76
Diluted (usd per share)	0.38	0.34	0.69	0.75
Cash dividends declared per common share (in dollars per share)	$ 0.19	$ 0.19	$ 0.19	$ 0.19
Weighted average shares outstanding:
Basic (in shares)	52,432,822	52,099,694	52,389,989	52,160,348
Diluted (in shares)	53,603,932	52,750,401	53,736,134	52,885,491