Note 7 - Loans - Impaired Loans and Related Allowance for Credit Losses (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Loans with no related allowance, unpaid principal balance	$ 79,440,000		$ 95,807,000
Loans with no related allowance, recorded investment	98,736,000		88,342,000
Loans with related allowance, unpaid principal balance	31,805,000		28,637,000
Loans with related allowance, recorded investment	29,640,000		26,732,000
Allowance	2,275,000		2,796,000
Total impaired loans, unpaid principal balance	111,245,000		124,444,000
Total impaired loans, recorded investment	128,376,000	$ 115,100,000	115,074,000
Commercial Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	19,836,000		24,037,000
Loans with no related allowance, recorded investment	17,973,000		23,121,000
Loans with related allowance, unpaid principal balance	2,410,000		5,216,000
Loans with related allowance, recorded investment	1,979,000		4,640,000
Allowance	1,062,000		1,827,000
Real Estate Construction Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	5,776,000		5,776,000
Loans with no related allowance, recorded investment	33,044,000		5,458,000
Commercial Real Estate Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	49,567,000		60,522,000
Loans with no related allowance, recorded investment	43,458,000		54,453,000
Loans with related allowance, unpaid principal balance	16,282,000		10,158,000
Loans with related allowance, recorded investment	15,814,000		10,017,000
Allowance	818,000		573,000
Residential Mortgage and Equity Lines Portfolio Segment [Member]
Loans with no related allowance, unpaid principal balance	4,261,000		5,472,000
Loans with no related allowance, recorded investment	4,261,000		5,310,000
Loans with related allowance, unpaid principal balance	13,113,000		13,263,000
Loans with related allowance, recorded investment	11,847,000		12,075,000
Allowance	$ 395,000		$ 396,000