Note 13 - Fair Value - Quantitative Information for Assets Measured at Fair Value on Nonrecurring Basis (Details) - Fair Value, Measurements, Nonrecurring [Member] - Valuation, Market Approach [Member]		3 Months Ended
		Mar. 31, 2018	Dec. 31, 2017
Unobservable Input	[1]	Appraisal adjustments(2)
Minimum [Member] | Measurement Input, Discount Rate [Member]
Discount range, impaired loans		7	6
Discount range, non-covered OREO		10	8
Discount range, covered OREO		26	0
Maximum [Member] | Measurement Input, Discount Rate [Member]
Discount range, impaired loans		100	79
Discount range, non-covered OREO		61	47
Discount range, covered OREO		49	65
Weighted Average [Member] | Measurement Input, Discount Rate [Member]
Discount range, impaired loans		37	34
Discount range, non-covered OREO		23	32
Discount range, covered OREO		44	52

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