Note 11 - Income Taxes (Details Textual)	3 Months Ended		12 Months Ended
	Mar. 31, 2016 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)
Domestic Tax Authority [Member]
Operating Loss Carryforwards			$ 261,000,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards			$ 191,000,000
Investment Tax Credit Carryforward [Member] | Minimum [Member]
Tax Credit Carryforward Expiration Year			2,022
Investment Tax Credit Carryforward [Member] | Maximum [Member]
Tax Credit Carryforward Expiration Year			2,024
Investment Tax Credit Carryforward [Member]
Tax Credit Carryforward Expiration Period			20 years
General Business Tax Credit Carryforward [Member] | Minimum [Member]
Tax Credit Carryforward Expiration Year			2,026
General Business Tax Credit Carryforward [Member]
Tax Credit Carryforward Expiration Period			20 years
Effective Income Tax Rate Reconciliation, Percent	22.97%	33.10%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	35.00%
Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount	$ 1,100,000	$ 1,146,000
Deferred Tax Assets, Investments			$ 1,300,000
Deferred Tax Assets, Tax Credit Carryforwards, General Business			70,800,000
Undistributed Earnings of Foreign Subsidiaries			$ 233,800,000