Note 17 - Fair Value - Quantitative Information for Assets Measured at Fair Value on Nonrecurring Basis (Details) - Fair Value, Nonrecurring [Member] - Measurement Input, Discount Rate [Member] - Valuation, Market Approach [Member]		Dec. 31, 2020	Dec. 31, 2019
Minimum [Member]
Discount range, impaired loans	[1],[2]	0.22	0.22
Discount range, non-covered OREO	[1],[2]	0.08	0.15
Maximum [Member]
Discount range, impaired loans	[1],[2]	0.38	0.36
Discount range, non-covered OREO	[1],[2]	0.77	1
Weighted Average [Member]
Discount range, impaired loans	[1],[2]	(0.30)	(0.26)
Discount range, non-covered OREO	[1],[2]	(0.25)	(0.08)

[1] Appraisals may be adjusted by management for customized discounting criteria, estimated sales costs, and proprietary qualitative adjustments.

[2] Fair value is generally based on appraisals of the underlying collateral.