Note 4 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Impaired Loans, Average Investment and Interest Income (Details) - USD ($)		3 Months Ended				12 Months Ended
		Mar. 31, 2016		Mar. 31, 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]	$ 682,000				$ 612,000
Interest income recognized on impaired loans, after designation as impaired		0				23,000
Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member]
Average recorded investment in impaired loans(1)	[1],[2]	667,000		$ 501,000		681,000
Interest income recognized on impaired loans, after designation as impaired		10,000	[2]	7,000		43,000	[2]
Consumer Real Estate Portfolio Segment [Member] | Closed End Junior Liens [Member]
Average recorded investment in impaired loans(1)	[1],[2]	216,000		236,000		228,000
Interest income recognized on impaired loans, after designation as impaired	[2]	4,000		4,000		15,000
Consumer Real Estate Portfolio Segment [Member] | Investor Owned Residential Real Estate [Member]
Average recorded investment in impaired loans(1)	[1],[2]	75,000		76,000		76,000
Interest income recognized on impaired loans, after designation as impaired	[2]	1,000		1,000		5,000
Commercial Real Estate Portfolio Segment [Member] | Multifamily Real Estate [Member]
Average recorded investment in impaired loans(1)	[1],[2]	1,595,000		2,708,000		2,581,000
Interest income recognized on impaired loans, after designation as impaired		0	[1]	25,000	[2]	84,000	[1]
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member]
Average recorded investment in impaired loans(1)	[1],[2]	4,949,000		4,974,000		6,141,000
Interest income recognized on impaired loans, after designation as impaired	[1]	68,000		58,000		251,000
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member]
Average recorded investment in impaired loans(1)	[1],[2]	5,793,000		6,023,000		5,888,000
Interest income recognized on impaired loans, after designation as impaired	[1]	42,000		80,000		308,000
Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member]
Average recorded investment in impaired loans(1)	[1],[2]	819,000		674,000		1,090,000
Interest income recognized on impaired loans, after designation as impaired	[1]	0		(1,000)		40,000
Average recorded investment in impaired loans(1)	[1],[2],[3]	14,796,000		15,192,000		17,297,000
Interest income recognized on impaired loans, after designation as impaired	[1]	$ 125,000		$ 174,000		$ 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.