Note 23 - Income Taxes - Reconciliation of Income Taxes (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income tax at the federal statutory rate	34.00%	34.00%	34.00%
Deferred tax asset write-down	17.45%	5.02%
State franchise tax, net of federal tax benefit	6.46%	6.11%	5.79%
Amortization of affordable housing credit partnerships	4.82%	8.11%	5.91%
Officer life insurance	(2.50%)	(2.89%)	(1.81%)
Tax-exempt interest	(5.23%)	(10.85%)	(8.02%)
Affordable housing credits and benefits	(5.68%)	(11.69%)	(6.42%)
Other	(0.78%)	(0.68%)	(0.71%)
Effective Tax Rate	48.54%	27.13%	28.74%