Note 3 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Impaired Loans, Average Investment and Interest Income (Details) - USD ($) $ in Thousands		3 Months Ended			12 Months Ended
		Mar. 31, 2017		Mar. 31, 2016	Dec. 31, 2016
Average recorded investment in impaired loans(1)	[1],[2]	$ 9,123		$ 14,796	$ 11,585	[3]
Interest income recognized on impaired loans, after designation as impaired		67		125	553	[3]
Real Estate Construction Portfolio Segment[Member] | Construction, 1-4 Family Residential [Member]
Average recorded investment in impaired loans(1)	[1],[3]	267		682	462
Interest income recognized on impaired loans, after designation as impaired	[3]	3		0	10
Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member]
Average recorded investment in impaired loans(1)	[1],[3]	606		667	642
Interest income recognized on impaired loans, after designation as impaired	[3]	9		10	38
Consumer Real Estate Portfolio Segment [Member] | Closed End Junior Liens [Member]
Average recorded investment in impaired loans(1)	[1],[3]	193		216	207
Interest income recognized on impaired loans, after designation as impaired	[3]	3		4	13
Consumer Real Estate Portfolio Segment [Member] | Investor Owned Residential Real Estate [Member]
Average recorded investment in impaired loans(1)	[1],[3]	73		75	74
Interest income recognized on impaired loans, after designation as impaired	[3]	1		1	4
Commercial Real Estate Portfolio Segment [Member] | Multifamily Real Estate [Member]
Average recorded investment in impaired loans(1)	[1],[3]	1,091		1,595	1,366
Interest income recognized on impaired loans, after designation as impaired	[3]			0	12
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member]
Average recorded investment in impaired loans(1)	[1],[3]	3,945		4,949	4,342
Interest income recognized on impaired loans, after designation as impaired	[3]	32		68	206
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member]
Average recorded investment in impaired loans(1)	[1],[3]	2,708		5,793	3,947
Interest income recognized on impaired loans, after designation as impaired	[3]	17		42	263
Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member]
Average recorded investment in impaired loans(1)	[1],[3]	237		819	541
Interest income recognized on impaired loans, after designation as impaired	[3]	2		$ 0	7
Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member]
Average recorded investment in impaired loans(1)		3	[1]		4
Interest income recognized on impaired loans, after designation as impaired		$ 0			$ 0	[3]

[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.