Note 7 - Employee Benefits Plans (Details Textual)	3 Months Ended	12 Months Ended
	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Defined Contribution Plan, Cost		$ 40,000	$ 16,000
Cash Surrender Value of Life Insurance				$ 22,300,000
Policy Loans and Accrued Interest				$ 5,500,000
Debt Instrument, Interest Rate, Stated Percentage				13.13%
Cash Surrender Value Borrowed Portion Fixed Rate of Return, Percentage				12.63%
Net Borrowing Cost, Percentage				0.50%
Cash Surrender Value Non Borrowed Portion, Fixed Rate of Return Percentage				4.00%
Proceeds from Life Insurance Policy	$ 28,100,000		28,139,000
Payments for (Proceeds from) Life Insurance Policies			(22,400,000)
Other Comprehensive Income (Loss), Tax		95,000
Defined Benefit Plan, Accumulated Benefit Obligation		0
Other Postretirement Benefits Cost (Reversal of Cost)		$ 0
Minimum [Member]
Health Care Benefits Age of Eligible Retired Employees		55
Maximum [Member]
Health Care Benefits Age of Eligible Retired Employees		65
Operating Income (Loss) [Member]
Operating Loss Carryforwards			$ 24,000,000