Note 4 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Impaired Loans, Average Investment and Interest Income (Details) - USD ($)		9 Months Ended			12 Months Ended
		Sep. 30, 2016	Sep. 30, 2015		Dec. 31, 2015
Real Estate Construction Portfolio Segment[Member] | Construction, 1-4 Family Residential [Member]
Average recorded investment in impaired loans(1)	[1],[2]	$ 529,000			$ 612,000
Interest income recognized on impaired loans, after designation as impaired	[1]	0			23,000
Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member]
Average recorded investment in impaired loans(1)	[1],[2]	652,000	$ 685,000		681,000
Interest income recognized on impaired loans, after designation as impaired	[1]	28,000	33,000		43,000
Consumer Real Estate Portfolio Segment [Member] | Closed End Junior Liens [Member]
Average recorded investment in impaired loans(1)	[1],[2]	210,000	231,000		228,000
Interest income recognized on impaired loans, after designation as impaired	[1]	10,000	11,000		15,000
Consumer Real Estate Portfolio Segment [Member] | Investor Owned Residential Real Estate [Member]
Average recorded investment in impaired loans(1)	[1],[2]	74,000	76,000		76,000
Interest income recognized on impaired loans, after designation as impaired	[1]	3,000	4,000		5,000
Commercial Real Estate Portfolio Segment [Member] | Multifamily Real Estate [Member]
Average recorded investment in impaired loans(1)	[1],[2]	1,741,000	2,670,000		2,581,000
Interest income recognized on impaired loans, after designation as impaired	[1]	7,000	0		84,000
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member]
Average recorded investment in impaired loans(1)	[1],[2]	4,629,000	5,302,000		6,141,000
Interest income recognized on impaired loans, after designation as impaired	[1]	175,000	86,000		251,000
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member]
Average recorded investment in impaired loans(1)	[1],[2]	4,372,000	5,924,000		5,888,000
Interest income recognized on impaired loans, after designation as impaired	[1]	252,000	128,000		308,000
Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member]
Average recorded investment in impaired loans(1)	[1],[2]	697,000	1,014,000		1,090,000
Interest income recognized on impaired loans, after designation as impaired	[1]	1,000	5,000		40,000
Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member]
Average recorded investment in impaired loans(1)	[2]	4,000
Interest income recognized on impaired loans, after designation as impaired		0
Average recorded investment in impaired loans(1)	[2],[3]	12,908,000	15,902,000	[1]	17,297,000
Interest income recognized on impaired loans, after designation as impaired		$ 476,000	$ 267,000	[1]	$ 769,000

[1] Only classes with impaired loans are shown.

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

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