Segment Reporting - Sales by Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues
Revenues	$ 971,578	$ 717,699	$ 901,238
Gross profit	118,987	74,076	105,137
Selling, general & administrative expenses	69,406	68,228	64,501
Goodwill and other impairment	0	29,017	0
Operating income (loss)	49,581	(23,169)	40,636
Capital expenditures and depreciation expense:
Capital expenditures	17,653	7,142	24,117
Depreciation expense	15,059	15,059	13,562
Vehicle Solutions
Revenues
Revenues	498,913	366,636	577,989
Warehouse Automation
Revenues
Revenues	187,912	101,655	12,803
Electrical Systems
Revenues
Revenues	168,971	141,094	178,398
Aftermarket and Accessories
Revenues
Revenues	115,782	108,314	132,048
Operating Segments | Vehicle Solutions
Revenues
Revenues	498,913	366,636	577,989
Gross profit	50,608	32,398	65,121
Selling, general & administrative expenses	26,959	22,510	24,875
Goodwill and other impairment		7,245
Operating income (loss)	23,649	2,643	40,246
Capital expenditures and depreciation expense:
Capital expenditures	6,203	3,599	13,967
Depreciation expense	7,911	7,682	6,876
Operating Segments | Warehouse Automation
Revenues
Revenues	187,912	101,655	12,803
Gross profit	29,669	13,205	1,248
Selling, general & administrative expenses	6,106	9,698	1,396
Goodwill and other impairment		19,829
Operating income (loss)	23,563	(16,322)	(148)
Capital expenditures and depreciation expense:
Capital expenditures	4,480	1,288	433
Depreciation expense	687	377	49
Operating Segments | Electrical Systems
Revenues
Revenues	168,971	141,094	178,398
Gross profit	20,773	12,185	16,588
Selling, general & administrative expenses	6,213	3,996	5,331
Goodwill and other impairment		1,150
Operating income (loss)	14,560	7,039	11,257
Capital expenditures and depreciation expense:
Capital expenditures	5,976	857	6,586
Depreciation expense	3,550	3,552	3,027
Operating Segments | Aftermarket and Accessories
Revenues
Revenues	115,782	108,314	132,048
Gross profit	17,980	16,658	22,252
Selling, general & administrative expenses	5,889	5,396	6,594
Goodwill and other impairment		0
Operating income (loss)	12,091	11,262	15,658
Capital expenditures and depreciation expense:
Capital expenditures	482	358	463
Depreciation expense	1,240	1,436	1,126
Corporate/ Other
Revenues
Revenues	0	0	0
Gross profit	(43)	(370)	(72)
Selling, general & administrative expenses	24,239	26,628	26,305
Goodwill and other impairment		793
Operating income (loss)	(24,282)	(27,791)	(26,377)
Capital expenditures and depreciation expense:
Capital expenditures	512	1,040	2,668
Depreciation expense	$ 1,671	$ 2,012	$ 2,484