Note 16 - Fair Value Measurements - Level 3 Fair Value Measurements (Details)		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Minimum [Member] | Impaired loans [Member] | Present Value of Cash Flows [Member]
Discount rate		5.50%	6.75%
Minimum [Member] | Other Real Estate Owned [Member] | Discounted Appraised Value [Member]
Discount rate		1.68%	0.00%
Selling cost	[1]	2.00%	2.91%
Maximum [Member] | Impaired loans [Member] | Present Value of Cash Flows [Member]
Discount rate		13.25%	8.00%
Maximum [Member] | Other Real Estate Owned [Member] | Discounted Appraised Value [Member]
Discount rate		68.33%	53.46%
Selling cost		6.01%	8.60%
Weighted Average [Member] | Impaired loans [Member] | Present Value of Cash Flows [Member]
Discount rate		5.92%	7.35%
Weighted Average [Member] | Other Real Estate Owned [Member] | Discounted Appraised Value [Member]
Discount rate		11.07%	13.66%
Selling cost		4.72%	6.48%

[1] The Company markets other real estate owned both independently and with local realtors. Properties marketed by realtors are discounted by selling costs. Properties that the Company markets independently are not discounted by selling costs.