Note 6 - Goodwill and Intangibles - Core Deposit Intangibles (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Balance at the beginning of period	$ 17,450	$ 9,079
Amortization expense	(2,266)	(1,692)	$ (1,001)
Balance at the end of the period	14,970	17,450	9,079
Net book value	14,970	17,450	9,079	$ 14,970	$ 17,450	$ 9,079
Core Deposits [Member]
Balance at the beginning of period	15,595	9,079	7,381
Amortization expense	(2,129)	(1,692)	(1,001)
Balance at the end of the period	13,466	15,595	9,079
Gross carrying amount				19,255	19,255	11,046
Accumulated amortization				(5,789)	(3,660)	(1,967)
Net book value	$ 13,466	15,595	9,079	$ 13,466	$ 15,595	$ 9,079
Core Deposits [Member] | Springfield Bancshares
Core deposit intangible from acquisition		$ 8,208
Core Deposits [Member] | Guaranty Bank [Member]
Core deposit intangible from acquisition			$ 2,699