Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Sales of goods	$ 117,727	$ 118,070	$ 215,356	$ 225,985
Sales of services	27,133	17,924	48,206	36,319
Total net sales	144,860	135,994	263,562	262,304
Cost of goods sold	94,291	92,638	173,692	179,031
Cost of services sold	22,833	15,543	40,882	31,500
Total cost of sales	117,124	108,181	214,574	210,531
Gross profit	27,736	27,813	48,988	51,773
Selling and administrative expenses	20,578	23,317	39,805	46,134
Amortization expense	1,695	2,789	3,454	6,055
Asset impairments	0	128,938	0	128,938
Interest expense	2,181	1,652	4,289	2,822
Interest income	(54)	(52)	(110)	(107)
Equity in (income) loss of nonconsolidated investments	(145)	487	55	683
Other (income) expense	(18)	107	(13)	822
Total operating expenses	24,237	157,238	47,480	185,347
Income (loss) before income taxes	3,499	(129,425)	1,508	(133,574)
Income tax expense (benefit)	475	(37,429)	906	(38,746)
Net income (loss)	$ 3,024	$ (91,996)	$ 602	$ (94,828)
Basic earnings (loss) per common share (usd per share)	$ 0.29	$ (8.96)	$ 0.06	$ (9.25)
Diluted earnings (loss) per common share (usd per share)	0.29	(8.96)	0.06	(9.25)
Dividends paid per common share (usd per share)	$ 0	$ 0.04	$ 0	$ 0.08