Note 7 - Financing Arrangements (Details Textual)	3 Months Ended
	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)
Revolving Credit Facility [Member] | Letter of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 500,000
Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR) [Member]
Derivative, Basis Spread on Variable Rate	1.50%
Revolving Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 20,000,000
Line of Credit Facility, Commitment Fee Percentage	0.15%
Minimum Consolidated Tangible Net Worth	$ 22,000,000
Minimum Fixed Charge Coverage Ratio	1.35
Minimum Asset Coverage Ratio	1.75
Maximum Leverage Ratio	3.5
Secured Long-term Debt, Noncurrent		$ 7,000,000