Industry Segments - Schedule of reporting information by segment (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information [Line Items]
Net sales		$ 233,156	$ 187,369	$ 458,642	$ 361,798
Total operating income		22,617	15,869	47,022	26,734
Interest expense, net		(1,211)	(999)	(2,358)	(1,994)
Income before income taxes		21,406	14,870	44,664	24,740
Operating Segments [Member] | Material Handling [Member]
Segment Reporting Information [Line Items]
Net sales		173,090	137,227	349,726	267,120
Total operating income	[1]	28,034	17,902	59,254	34,829
Operating Segments [Member] | Distribution [Member]
Segment Reporting Information [Line Items]
Net sales		60,075	50,156	108,936	94,706
Total operating income	[2]	4,269	4,214	7,570	5,652
Inter-company sales [Member]
Segment Reporting Information [Line Items]
Net sales		(9)	(14)	(20)	(28)
Corporate [Member]
Segment Reporting Information [Line Items]
Total operating income	[2]	$ (9,686)	$ (6,247)	$ (19,802)	$ (13,747)

[1] In the quarter and six months ended June 30, 2021, the Company recognized a $1.0 million gain on the sale of a building within the Material Handling Segment as described in Note 4.

[2] In the six months ended June 30, 2021, the Company recognized $0.8 million of executive severance, of which $0.5 million was recognized in the Distribution Segment and $0.3 million was recognized in Corporate. This executive severance cost includes $0.5 million of severance and benefits and $0.3 million of charges for acceleration of stock compensation.