Note 4 - Commitments and Contingent Liabilities (Details Textual) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended		64 Months Ended
	Jul. 31, 2015	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2015	Jun. 30, 2014	Mar. 31, 2015	Dec. 31, 2014	Nov. 30, 2009
Letter of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity		$ 20,000,000		$ 20,000,000
Revolving Credit Facility [Member] | GM [Member]
Long-term Line of Credit		2,374,000		2,374,000			$ 3,043,000
GM [Member]
Line of Credit Facility, Capacity Available for Trade Purchases		10,000,000		10,000,000
Utilimaster [Member]
Payments for Previous Acquisition			$ 1,500,000			$ 6,569,000
Subsequent Event [Member]
Litigation Settlement, Amount	$ (1,000,000)
Equal Installment Period for Penalty Pertaining to Early Warning and Defect Reporting	3 years
Business Combination, Contingent Consideration, Liability			$ 0			$ 0
Letters of Credit Outstanding, Amount		1,368,000		1,368,000			$ 4,742,000
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High								$ 7,000,000
Payments for Previous Acquisition				162,000	$ 162,000
Litigation Settlement, Amount		$ (1,056,000)		$ (2,269,000)