Note 4 - Accounts Receivable - Accounts Receivable (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Warranty claims	$ 9,473	$ 8,095
Other accounts receivable	12,753	22,409
Less allowance for bad debt and warranty claims	(826)	(663)
Total	183,875	156,199
Trade Accounts Receivable From Sale of Vehicles [Member]
Trade receivables	104,779	83,482
Trade Receivable Other Than Vehicles [Member]
Trade receivables	$ 57,697	$ 42,876