Note 13 - Income Taxes (Details Textual) - USD ($)		12 Months Ended
	Dec. 22, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	35.00%
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability			$ (82,900,000)
Deferred Tax Assets, Valuation Allowance			50,000	$ 255,000
Unrecognized Tax Benefits that Would Impact Effective Tax Rate			2,600,000	2,400,000
Unrecognized Tax Benefits, Interest on Income Taxes Accrued			21,050	34,800	$ 11,600
Unrecognized Tax Benefits, Income Tax Penalties Accrued			0
Unrecognized Tax Benefits, Interest on Income Taxes Expense			166,000	$ 145,000	$ 110,100
State and Local Jurisdiction [Member]
Operating Loss Carryforwards			$ 44,400,000
State and Local Jurisdiction [Member] | Latest Tax Year [Member]
Open Tax Year			2017
State and Local Jurisdiction [Member] | Earliest Tax Year [Member]
Open Tax Year			2013
State and Local Jurisdiction [Member] | Deferred Tax Assets Related to Operating Loss Carryforwards [Member]
Deferred Tax Assets, Valuation Allowance			$ 50,000
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount			$ (205,000)
Domestic Tax Authority [Member] | Latest Tax Year [Member]
Open Tax Year			2017
Domestic Tax Authority [Member] | Earliest Tax Year [Member]
Open Tax Year			2014
Scenario, Forecast [Member]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		21.00%