Industry Segments - Schedule of reporting information by segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Net sales	$ 139,115	$ 152,568
Total operating income	10,218	12,022
Interest expense, net	(1,049)	(1,639)
Income from continuing operations before income taxes	9,169	10,383
Operating Segments [Member] | Material Handling [Member]
Segment Reporting Information [Line Items]
Net sales	102,951	116,809
Total operating income	16,207	16,730
Operating Segments [Member] | Distribution [Member]
Segment Reporting Information [Line Items]
Net sales	36,174	35,781
Total operating income	213	1,738
Inter-company sales [Member]
Segment Reporting Information [Line Items]
Net sales	(10)	(22)
Corporate [Member]
Segment Reporting Information [Line Items]
Total operating income	$ (6,202)	$ (6,446)