Note 10 - Intangible Assets - Gross Carrying Amount and Accumulated Amortization of Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Finite-lived intangible assets, accumulated amortization	$ (3,077)		$ (2,802)
Finite-lived intangible assets, unamortized intangible assets	2,062
Goodwill, gross carrying amount	802		802
Goodwill, accumulated impairment	0		0
Goodwill	802	$ 802	802
Intangible assets (including goodwill), gross carrying amount	5,941		5,658
Intangible assets, unamortized intangible assets	2,864		2,856
Mortgage Servicing Rights [Member]
Finite-lived intangible assets, gross carrying amount	4,565		4,282
Finite-lived intangible assets, accumulated amortization	(2,734)		(2,558)
Finite-lived intangible assets, unamortized intangible assets	1,831		1,724
Core Deposits [Member]
Finite-lived intangible assets, gross carrying amount	574		574
Finite-lived intangible assets, accumulated amortization	(343)		(244)
Finite-lived intangible assets, unamortized intangible assets	$ 231		$ 330