Note 6 - Goodwill and Intangibles - Core Deposit Intangibles by Reportable Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Core deposit intangible	$ 11,381	$ 14,970	$ 17,450
Core Deposits [Member]
Segment Reporting Information [Line Items]
Core deposit intangible	11,381	13,466	15,595	$ 9,079
CRBT | Core Deposits [Member]
Segment Reporting Information [Line Items]
Core deposit intangible	2,189	2,684	3,186
CSB | Core Deposits [Member]
Segment Reporting Information [Line Items]
Core deposit intangible	3,305	3,980	4,675
SFCB | Core Deposits [Member]
Segment Reporting Information [Line Items]
Core deposit intangible	$ 5,887	$ 6,802	$ 7,734