Note 6 - Goodwill and Intangibles - Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Balance at the beginning of period	$ 77,832	$ 28,334	$ 13,111
Goodwill from acquisition		49,741	15,223
Goodwill impairment	(3,000)
Balance at the end of period	74,748	77,832	28,334
Springfield Bancshares
Goodwill from acquisition		45,975
Bates Companies [Member]
Goodwill from acquisition		3,766
Goodwill from acquisition - measurement period adjustment	(84)
Goodwill impairment	(3,000)
Balance at the end of period	$ 3,700
Guaranty Bank [Member]
Goodwill from acquisition			$ 15,223
Goodwill from acquisition - measurement period adjustment		$ (243)