Note 3 - Loans and Allowance for Loan Losses - Acquired Impaired Loans Accretable Yield (Details) - USD ($)		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Balance at beginning of period		$ 1,658,000	$ 6,602,000	$ 1,726,000	$ 5,193,000
Additions		2,000	224,000	223,000	245,000
Accretion income		(141,000)	(638,000)	(429,000)	(1,992,000)
Net reclassification from nonaccretable to accretable		83,000	1,000,000	330,000	4,565,000
Reductions	[1]	(23,000)	(407,000)	(271,000)	(1,230,000)
Balance at end of period		$ 1,579,000	$ 6,781,000	$ 1,579,000	$ 6,781,000

[1] Reductions primarily reflect the result of exit events, including loan payoffs and charge-offs.