Industry Segments - Schedule of reporting information by segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Net sales	$ 116,818	$ 125,480	$ 134,285	$ 139,115	$ 138,388	$ 135,219	$ 140,560	$ 152,568	$ 515,698	$ 566,735	$ 547,043
Total operating income	8,806	$ 8,060	$ 10,182	$ 10,218	7,033	$ (25,839)	$ 13,111	$ 12,022	37,266	6,327	24,888
Interest expense, net									(4,083)	(4,938)	(7,292)
Loss on extinguishment of debt									0	0	(1,888)
Income from continuing operations before income taxes									33,183	1,389	15,708
Total Assets	353,139				348,645				353,139	348,645	355,942
Capital Additions, Net									10,294	5,123	5,814
Depreciation and Amortization									23,583	26,139	30,831
Operating Segments [Member] | Material Handling [Member]
Segment Reporting Information [Line Items]
Net sales									356,407	417,199	391,313
Total operating income									53,144	57,948	38,874
Total Assets	193,751				229,962				193,751	229,962	257,863
Capital Additions, Net									8,835	4,500	5,165
Depreciation and Amortization									21,282	24,159	28,506
Operating Segments [Member] | Distribution [Member]
Segment Reporting Information [Line Items]
Net sales									159,349	149,636	156,428
Total operating income									10,076	7,441	9,073
Total Assets	75,338				48,575				75,338	48,575	49,822
Capital Additions, Net									1,396	587	622
Depreciation and Amortization									1,501	1,169	1,174
Inter-company sales [Member]
Segment Reporting Information [Line Items]
Net sales									(58)	(100)	(698)
Corporate [Member]
Segment Reporting Information [Line Items]
Total operating income									(25,954)	(59,062)	(23,059)
Total Assets	$ 84,050				$ 70,108				84,050	70,108	48,257
Capital Additions, Net									63	36	27
Depreciation and Amortization									$ 800	$ 811	$ 1,151