Note 11 - Income Taxes (Details Textual) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Income Taxes Receivable	$ 7.2	$ 7.2	$ 14.6
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability	23.4
Low income Housing Tax Credit Investments, Pretax Write-down	$ 2.6	$ 2.6