Industry Segments - Schedule of reporting information by segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Net sales	$ 122,250	$ 139,115
Total operating income	23,298	10,218
Interest expense, net	(1,069)	(1,049)
Income from continuing operations before income taxes	22,229	9,169
Operating Segments [Member] | Material Handling [Member]
Segment Reporting Information [Line Items]
Net sales	84,076	102,951
Total operating income	15,167	16,207
Operating Segments [Member] | Distribution [Member]
Segment Reporting Information [Line Items]
Net sales	38,195	36,174
Total operating income	1,850	213
Inter-company sales [Member]
Segment Reporting Information [Line Items]
Net sales	(21)	(10)
Corporate [Member]
Segment Reporting Information [Line Items]
Total operating income	$ 6,281	$ (6,202)