Note 10 - Restrictions on Dividends (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-04, Cash Dividends Paid to Registrant, Consolidated Subsidiaries	$ 28,556	$ 9,419	$ 8,141
Period of Restriction on Retained Net Income Without Prior Approval	2 years
Statutory Accounting Practices, Statutory Amount Available for Dividend Payments without Regulatory Approval	$ 3,347