Note 6 - Valuation Accounts - Valuation and Allowance Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Parts Inventory [Member]
Balance	$ 7,460	$ 9,315	$ 7,661
Net Charged to Costs and Expenses	7,378	3,520	4,501
Net Write-Offs	(5,415)	(5,375)	(2,847)
Balance End of Year	9,423	7,460	9,315
Commercial Vehicle Inventory [Member]
Balance	919	6,075	9,602
Net Charged to Costs and Expenses	13,653	(536)	9,598
Net Write-Offs	(7,507)	(4,620)	(13,125)
Balance End of Year	$ 7,065	$ 919	$ 6,075