Note 16 - Income Taxes (Details Textual) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revaluation of Deferred Tax Asset, Decrease					$ 3,851
Reclassification of Existing AMT Tax Credits					$ 8,913
Budget Sequestration Rate					6.60%
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount		$ (703)		$ (703)
Effective Income Tax Rate Reconciliation, Alternative Minimum Tax Sequestration, Amount	$ 569			569
Income Taxes Receivable, Current	5,087		2,510	5,087
Deferred Tax Assets, Valuation Allowance, Total	162		142	162
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount			$ (20)	(42)
Earliest Tax Year [Member]
Operating Loss Carryforwards, Expiration Date			Dec. 31, 2031
Latest Tax Year [Member]
Operating Loss Carryforwards, Expiration Date			Dec. 31, 2037
Domestic Tax Authority [Member]
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax			$ 2,155
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration			53,728
State and Local Jurisdiction [Member]
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration			$ 31,977
Alternative Minimum Tax Credit [Member]
Tax Credit Carryforward, Reduction Amount					$ 569
Income Taxes Receivable, Current	$ 5,087			$ 5,087