Note 6 - Goodwill and Intangibles - Core Deposit Intangibles by Reportable Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Core deposit intangible	$ 14,970	$ 17,450	$ 9,079
Core Deposits [Member]
Segment Reporting Information [Line Items]
Core deposit intangible	13,466	15,595	9,079	$ 7,381
CRBT | Core Deposits [Member]
Segment Reporting Information [Line Items]
Core deposit intangible	2,684	3,186	3,694
CSB | Core Deposits [Member]
Segment Reporting Information [Line Items]
Core deposit intangible	3,980	4,675	$ 5,385
SFC Bank
Segment Reporting Information [Line Items]
Core deposit intangible	6,802	7,735
SFC Bank | Core Deposits [Member]
Segment Reporting Information [Line Items]
Core deposit intangible	$ 6,802	$ 7,734