Note 4 - Fair Value Measurements (Details Textual) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value, Ending Balance	$ 66,409
Fair Value, Nonrecurring [Member]
Loans Receivable, Fair Value Disclosure	100	1,300
Fair Value, Inputs, Level 3 [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value, Ending Balance	$ 9,800	$ 9,400