Note 5 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Impaired Loans, Average Investment and Interest Income (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Average recorded investment in impaired loans(1)	[2]	$ 11,585	[1]	$ 17,297	[1]	$ 16,311	[3]
Income recognized on impaired loans, after designation as impaired		553		769		473	[3]
Real Estate Construction Portfolio Segment[Member] | Construction, 1-4 Family Residential [Member]
Average recorded investment in impaired loans(1)	[2],[3]	462		612
Income recognized on impaired loans, after designation as impaired	[3]	10		23
Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member]
Average recorded investment in impaired loans(1)	[2],[3]	642		681		555
Income recognized on impaired loans, after designation as impaired	[3]	38		43		31
Consumer Real Estate Portfolio Segment [Member] | Closed End Junior Liens [Member]
Average recorded investment in impaired loans(1)	[2],[3]	207		228		249
Income recognized on impaired loans, after designation as impaired	[3]	13		15		16
Consumer Real Estate Portfolio Segment [Member] | Investor Owned Residential Real Estate [Member]
Average recorded investment in impaired loans(1)	[2],[3]	74		76		77
Income recognized on impaired loans, after designation as impaired	[3]	4		5		5
Commercial Real Estate Portfolio Segment [Member] | Multifamily Real Estate [Member]
Average recorded investment in impaired loans(1)	[2],[3]	1,366		2,581		2,773
Income recognized on impaired loans, after designation as impaired	[3]	12		84		0
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member]
Average recorded investment in impaired loans(1)	[2],[3]	4,342		6,141		5,836
Income recognized on impaired loans, after designation as impaired	[3]	206		251		203
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member]
Average recorded investment in impaired loans(1)	[2],[3]	3,947		5,888		6,114
Income recognized on impaired loans, after designation as impaired	[3]	263		308		175
Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member]
Average recorded investment in impaired loans(1)	[2],[3]	541		1,090		707
Income recognized on impaired loans, after designation as impaired	[3]	7		$ 40		$ 43
Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member]
Average recorded investment in impaired loans(1)	[2]	4
Income recognized on impaired loans, after designation as impaired		$ 0

[1] Recorded investment is net of charge-offs and interest paid while a loan is in nonaccrual status.

[2] Recorded investment is net of charge-offs and interest paid while a loan is in nonaccrual status.

[3] Only classes with impaired loans are shown.