Note 10 - Purchase of Financial Assets (Details Textual) - USD ($) $ in Millions	3 Months Ended	47 Months Ended
	Mar. 31, 2018	Mar. 31, 2018
Loan Purchase Agreement Financial Asset for Which Transfer Is Accounted as a Purchase Total Commitment to Purchase	$ 50.0
Loan Purchase Agreement Financial Asset for Which Transfer is Accounted as a Purchase Par Value Purchased		$ 122.3
Loan Purchase Agreement Financial Asset for Which Transfer Is Accounted as a Purchase Net Discount Premium		77.3
Payments for Loans		$ 45.0