Note 7 - Fair Value Measurements (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other-than-temporary Impairment Loss, Debt Securities, Portion Recognized in Earnings, Total	$ 0	$ 0	$ 300
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Ending Balance	58,500	17,800
Loans Receivable Held-for-sale, Mortgage, Unpaid Principal Balance	$ 191,300	143,900
Minimum [Member]
Short Term Borrowings Maturity Period	30 days
Fair Value, Inputs, Level 2 [Member] | Under Commitment to Sell [Member]
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Ending Balance	$ 136,800	130,800
Fair Value, Inputs, Level 2 [Member] | Not Under Commitment to Sell [Member]
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Ending Balance	$ 60,200	$ 18,500