Note 8 - Loans - Allowance for Loan Losses by Portfolio Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Beginning Balance	$ 166,538	$ 123,224
Provision/(reversal) for possible credit losses	(12,110)	25,000
Charge-offs	(9,138)	(1,321)
Recoveries	(1,380)	(1,370)
Net (charge-offs)/recoveries	(7,758)	49
Ending Balance	147,264	148,273
Recoveries	1,380	1,370
Reserve for impaired loans		3,451
Reserve for non-impaired loans		144,822
Reserve for off-balance sheet credit commitments		3,013
Commitments to Extend Credit [Member]
Beginning Balance	5,880
Provision/(reversal) for possible credit losses	(1,449)
Ending Balance	4,970
Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member]
Beginning Balance	594
Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member] | Commitments to Extend Credit [Member]
Beginning Balance	539
Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Beginning Balance	167,132
Cumulative Effect, Period of Adoption, Adjusted Balance [Member] | Commitments to Extend Credit [Member]
Beginning Balance	6,419
Commercial Portfolio Segment [Member]
Beginning Balance	68,742	57,021
Provision/(reversal) for possible credit losses	12,627	10,891
Charge-offs	(9,138)	(1,321)
Recoveries	(1,269)	(1,208)
Net (charge-offs)/recoveries	(7,869)	(113)
Ending Balance	44,752	67,799
Recoveries	1,269	1,208
Reserve for impaired loans		2,827
Reserve for non-impaired loans		64,972
Reserve for off-balance sheet credit commitments		1,296
Commercial Portfolio Segment [Member] | Commitments to Extend Credit [Member]
Beginning Balance	4,802
Provision/(reversal) for possible credit losses	125
Ending Balance	1,580
Commercial Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member]
Beginning Balance	(28,748)
Commercial Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member] | Commitments to Extend Credit [Member]
Beginning Balance	(3,347)
Commercial Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Beginning Balance	39,994
Commercial Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member] | Commitments to Extend Credit [Member]
Beginning Balance	1,455
Real Estate Construction Portfolio Segment [Member]
Beginning Balance	30,854	19,474
Provision/(reversal) for possible credit losses	446	3,748
Charge-offs	0	0
Recoveries	0	0
Net (charge-offs)/recoveries	0	0
Ending Balance	5,968	23,222
Recoveries	(0)	0
Reserve for impaired loans		0
Reserve for non-impaired loans		23,222
Reserve for off-balance sheet credit commitments		1,233
Real Estate Construction Portfolio Segment [Member] | Commitments to Extend Credit [Member]
Beginning Balance	690
Provision/(reversal) for possible credit losses	(1,574)
Ending Balance	3,390
Real Estate Construction Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member]
Beginning Balance	(25,332)
Real Estate Construction Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member] | Commitments to Extend Credit [Member]
Beginning Balance	4,274
Real Estate Construction Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Beginning Balance	5,522
Real Estate Construction Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member] | Commitments to Extend Credit [Member]
Beginning Balance	4,964
Commercial Real Estate Portfolio Segment [Member]
Beginning Balance	49,205	33,602
Provision/(reversal) for possible credit losses	(18,946)	6,129
Charge-offs	0	0
Recoveries	(95)	(155)
Net (charge-offs)/recoveries	95	155
Ending Balance	65,689	39,886
Recoveries	95	155
Reserve for impaired loans		405
Reserve for non-impaired loans		39,481
Reserve for off-balance sheet credit commitments		177
Commercial Real Estate Portfolio Segment [Member] | Commitments to Extend Credit [Member]
Beginning Balance	101
Provision/(reversal) for possible credit losses	0
Ending Balance	0
Commercial Real Estate Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member]
Beginning Balance	35,335
Commercial Real Estate Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member] | Commitments to Extend Credit [Member]
Beginning Balance	(101)
Commercial Real Estate Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Beginning Balance	84,540
Commercial Real Estate Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member] | Commitments to Extend Credit [Member]
Beginning Balance	0
Residential Mortgage and Equity Lines Portfolio Segment [Member]
Beginning Balance	17,737	13,108
Provision/(reversal) for possible credit losses	(6,231)	4,251
Charge-offs	0	0
Recoveries	(16)	(7)
Net (charge-offs)/recoveries	16	7
Ending Balance	30,852	17,366
Recoveries	16	7
Reserve for impaired loans		219
Reserve for non-impaired loans		17,147
Reserve for off-balance sheet credit commitments		304
Residential Mortgage and Equity Lines Portfolio Segment [Member] | Commitments to Extend Credit [Member]
Beginning Balance	284
Provision/(reversal) for possible credit losses	0
Ending Balance	0
Residential Mortgage and Equity Lines Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member]
Beginning Balance	19,330
Residential Mortgage and Equity Lines Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member] | Commitments to Extend Credit [Member]
Beginning Balance	(284)
Residential Mortgage and Equity Lines Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Beginning Balance	37,067
Residential Mortgage and Equity Lines Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member] | Commitments to Extend Credit [Member]
Beginning Balance	0
Installment and Other Loans [Member ]
Beginning Balance	0	19
Provision/(reversal) for possible credit losses	(6)	(19)
Charge-offs	0	0
Recoveries	0	0
Net (charge-offs)/recoveries	0	0
Ending Balance	3	0
Recoveries	(0)	0
Reserve for impaired loans		0
Reserve for non-impaired loans		0
Reserve for off-balance sheet credit commitments		$ 3
Installment and Other Loans [Member ] | Commitments to Extend Credit [Member]
Beginning Balance	3
Provision/(reversal) for possible credit losses	0
Ending Balance	0
Installment and Other Loans [Member ] | Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member]
Beginning Balance	9
Installment and Other Loans [Member ] | Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member] | Commitments to Extend Credit [Member]
Beginning Balance	(3)
Installment and Other Loans [Member ] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Beginning Balance	9
Installment and Other Loans [Member ] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member] | Commitments to Extend Credit [Member]
Beginning Balance	$ 0