Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Total net sales	$ 497,411	$ 616,428	$ 581,064
Total cost of sales	402,405	495,490	467,596
Gross profit	95,006	120,938	113,468
Selling and administrative expenses	73,644	82,524	82,745
Amortization expense (Note 4)	5,729	6,445	6,966
Concrete Tie Settlement expense (Note 18)	0	0	43,400
Interest expense - net	3,761	4,911	6,134
Other (income) expense - net (Note 19)	(2,110)	2,919	(1,208)
Income (loss) before income taxes	13,982	24,139	(24,569)
Income tax (benefit) expense	(11,841)	(23,835)	6,017
Income (loss) from continuing operations	25,823	47,974	(30,586)
Loss from discontinued operations before income taxes	(23,979)	(6,742)	(2,142)
Income tax benefit	(5,738)	(1,336)	(1,560)
Loss from discontinued operations (Note 3)	(18,241)	(5,406)	(582)
Net income (loss)	$ 7,582	$ 42,568	$ (31,168)
Basic earnings (loss) per common share from continuing operations (usd per share)	$ 2.45	$ 4.61	$ (2.95)
Basic earnings (loss) per common share from discontinued operations (usd per share)	(1.73)	(0.52)	(0.06)
Basic earnings (earnings) per common share (usd per share)	0.72	4.09	(3.01)
Diluted earnings (loss) per common share from continuing operations (usd per share)	2.42	4.51	(2.95)
Diluted earnings (loss) per common share from discontinued operations (usd per share)	(1.71)	(0.51)	(0.06)
Diluted earnings (loss) per common share (usd per share)	$ 0.71	$ 4.00	$ (3.01)
Sales of goods
Total net sales	$ 421,307	$ 505,200	$ 459,694
Total cost of sales	344,306	414,461	378,398
Sales of services
Total net sales	76,104	111,228	121,370
Total cost of sales	$ 58,099	$ 81,029	$ 89,198