Note 5 - Loans and the Allowance for Credit Losses - Loans by Origination and Risk Designation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Originated Current Fiscal Year	$ 138,210		$ 138,210		$ 444,378
Originated One Year Prior	437,520		437,520		1,873,427
Originated Two Years Prior	1,785,387		1,785,387		1,891,130
Originated Three Years Prior	1,881,718		1,881,718		419,300
Originated Four Years Prior	419,029		419,029		389,442
Originated Five or More Years Prior	1,824,000		1,824,000		1,497,749
Revolving Loans	1,676,636		1,676,636		1,836,415
Gross loans	8,162,500		8,162,500		8,351,841
Gross write-off, current year			0		54
Gross write-off, one year prior			0		3,397
Gross write-off, two years prior			0		0
Gross write-off, three years prior			0		0
Gross write-off, four years prior			0		280
Gross write-off, five years prior			6,481		13,236
Gross write-off, revolving			300		82
Gross write-off	3,595	$ 1,118	6,781	$ 5,602	17,049
Pass [Member]
Originated Current Fiscal Year	138,210		138,210		444,128
Originated One Year Prior	437,270		437,270		1,862,368
Originated Two Years Prior	1,773,558		1,773,558		1,888,446
Originated Three Years Prior	1,876,275		1,876,275		419,299
Originated Four Years Prior	417,395		417,395		387,013
Originated Five or More Years Prior	1,746,948		1,746,948		1,435,499
Revolving Loans	1,650,821		1,650,821		1,802,411
Gross loans	8,040,477		8,040,477		8,239,164
Special Mention [Member]
Originated Current Fiscal Year	0		0		0
Originated One Year Prior	0		0		10,620
Originated Two Years Prior	11,090		11,090		0
Originated Three Years Prior	2,810		2,810		0
Originated Four Years Prior	1,634		1,634		562
Originated Five or More Years Prior	25,635		25,635		28,270
Revolving Loans	22,647		22,647		14,716
Gross loans	63,816		63,816		54,168
Substandard [Member]
Originated Current Fiscal Year	0		0		250
Originated One Year Prior	250		250		439
Originated Two Years Prior	739		739		2,684
Originated Three Years Prior	2,633		2,633		1
Originated Four Years Prior	0		0		1,867
Originated Five or More Years Prior	51,417		51,417		33,980
Revolving Loans	3,168		3,168		19,288
Gross loans	58,207		58,207		58,509
Doubtful [Member]
Originated Current Fiscal Year	0		0		0
Originated One Year Prior	0		0		0
Originated Two Years Prior	0		0		0
Originated Three Years Prior	0		0		0
Originated Four Years Prior	0		0		0
Originated Five or More Years Prior	0		0		0
Revolving Loans	0		0		0
Gross loans	0		0		0
Commercial Portfolio Segment [Member]
Originated Current Fiscal Year	16,275		16,275		178,832
Originated One Year Prior	148,532		148,532		263,210
Originated Two Years Prior	206,888		206,888		265,946
Originated Three Years Prior	286,518		286,518		38,910
Originated Four Years Prior	34,087		34,087		14,900
Originated Five or More Years Prior	145,111		145,111		127,257
Revolving Loans	664,321		664,321		689,675
Gross loans	1,501,732		1,501,732		1,578,730
Gross write-off, current year			0		54
Gross write-off, one year prior			0		3,397
Gross write-off, two years prior			0		0
Gross write-off, three years prior			0		0
Gross write-off, four years prior			0		280
Gross write-off, five years prior			0		11,094
Gross write-off, revolving			300		63
Gross write-off	(0)	1,100	300	3,867	14,888
Commercial Portfolio Segment [Member] | Pass [Member]
Originated Current Fiscal Year	16,275		16,275		178,582
Originated One Year Prior	148,282		148,282		252,151
Originated Two Years Prior	195,059		195,059		265,705
Originated Three Years Prior	283,478		283,478		38,909
Originated Four Years Prior	32,453		32,453		13,726
Originated Five or More Years Prior	122,418		122,418		112,145
Revolving Loans	652,444		652,444		684,779
Gross loans	1,450,409		1,450,409		1,545,997
Commercial Portfolio Segment [Member] | Special Mention [Member]
Originated Current Fiscal Year	0		0		0
Originated One Year Prior	0		0		10,620
Originated Two Years Prior	11,090		11,090		0
Originated Three Years Prior	2,810		2,810		0
Originated Four Years Prior	1,634		1,634		562
Originated Five or More Years Prior	9,920		9,920		3,417
Revolving Loans	11,150		11,150		3,199
Gross loans	36,604		36,604		17,798
Commercial Portfolio Segment [Member] | Substandard [Member]
Originated Current Fiscal Year	0		0		250
Originated One Year Prior	250		250		439
Originated Two Years Prior	739		739		241
Originated Three Years Prior	230		230		1
Originated Four Years Prior	0		0		612
Originated Five or More Years Prior	12,773		12,773		11,695
Revolving Loans	727		727		1,697
Gross loans	14,719		14,719		14,935
Commercial Portfolio Segment [Member] | Doubtful [Member]
Originated Current Fiscal Year	0		0		0
Originated One Year Prior	0		0		0
Originated Two Years Prior	0		0		0
Originated Three Years Prior	0		0		0
Originated Four Years Prior	0		0		0
Originated Five or More Years Prior	0		0		0
Revolving Loans	0		0		0
Gross loans	0		0		0
Commercial Real Estate Portfolio Segment [Member]
Originated Current Fiscal Year	100,404		100,404		248,660
Originated One Year Prior	273,253		273,253		1,561,841
Originated Two Years Prior	1,534,768		1,534,768		1,586,997
Originated Three Years Prior	1,563,918		1,563,918		352,445
Originated Four Years Prior	357,702		357,702		354,646
Originated Five or More Years Prior	1,562,423		1,562,423		1,276,583
Revolving Loans	371,401		371,401		514,373
Gross loans	5,763,869		5,763,869		5,895,545
Gross write-off, current year			0		0
Gross write-off, one year prior			0		0
Gross write-off, two years prior			0		0
Gross write-off, three years prior			0		0
Gross write-off, four years prior			0		0
Gross write-off, five years prior			6,481		2,142
Gross write-off, revolving			0		0
Gross write-off	3,595	(0)	6,481	1,717	2,142
Commercial Real Estate Portfolio Segment [Member] | Pass [Member]
Originated Current Fiscal Year	100,404		100,404		248,660
Originated One Year Prior	273,253		273,253		1,561,841
Originated Two Years Prior	1,534,768		1,534,768		1,585,109
Originated Three Years Prior	1,562,051		1,562,051		352,445
Originated Four Years Prior	357,702		357,702		353,391
Originated Five or More Years Prior	1,509,393		1,509,393		1,232,240
Revolving Loans	371,401		371,401		497,588
Gross loans	5,708,972		5,708,972		5,831,274
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member]
Originated Current Fiscal Year	0		0		0
Originated One Year Prior	0		0		0
Originated Two Years Prior	0		0		0
Originated Three Years Prior	0		0		0
Originated Four Years Prior	0		0		0
Originated Five or More Years Prior	15,072		15,072		24,202
Revolving Loans	0		0		0
Gross loans	15,072		15,072		24,202
Commercial Real Estate Portfolio Segment [Member] | Substandard [Member]
Originated Current Fiscal Year	0		0		0
Originated One Year Prior	0		0		0
Originated Two Years Prior	0		0		1,888
Originated Three Years Prior	1,867		1,867		0
Originated Four Years Prior	0		0		1,255
Originated Five or More Years Prior	37,958		37,958		20,141
Revolving Loans	0		0		16,785
Gross loans	39,825		39,825		40,069
Commercial Real Estate Portfolio Segment [Member] | Doubtful [Member]
Originated Current Fiscal Year	0		0		0
Originated One Year Prior	0		0		0
Originated Two Years Prior	0		0		0
Originated Three Years Prior	0		0		0
Originated Four Years Prior	0		0		0
Originated Five or More Years Prior	0		0		0
Revolving Loans	0		0		0
Gross loans	0		0		0
Commercial Construction Portfolio Segment [Member]
Originated Current Fiscal Year	9,500		9,500		582
Originated One Year Prior	582		582		5,463
Originated Two Years Prior	2,124		2,124		15,645
Originated Three Years Prior	9,071		9,071		6,236
Originated Four Years Prior	6,236		6,236		0
Originated Five or More Years Prior	10,500		10,500		0
Revolving Loans	601,155		601,155		592,570
Gross loans	639,168		639,168		620,496
Gross write-off, current year			0		0
Gross write-off, one year prior			0		0
Gross write-off, two years prior			0		0
Gross write-off, three years prior			0		0
Gross write-off, four years prior			0		0
Gross write-off, five years prior			0		0
Gross write-off, revolving			0		0
Gross write-off	(0)	(0)	0	(0)	0
Commercial Construction Portfolio Segment [Member] | Pass [Member]
Originated Current Fiscal Year	9,500		9,500		582
Originated One Year Prior	582		582		5,463
Originated Two Years Prior	2,124		2,124		15,645
Originated Three Years Prior	9,071		9,071		6,236
Originated Four Years Prior	6,236		6,236		0
Originated Five or More Years Prior	10,500		10,500		0
Revolving Loans	590,251		590,251		583,870
Gross loans	628,264		628,264		611,796
Commercial Construction Portfolio Segment [Member] | Special Mention [Member]
Originated Current Fiscal Year	0		0		0
Originated One Year Prior	0		0		0
Originated Two Years Prior	0		0		0
Originated Three Years Prior	0		0		0
Originated Four Years Prior	0		0		0
Originated Five or More Years Prior	0		0		0
Revolving Loans	8,700		8,700		8,700
Gross loans	8,700		8,700		8,700
Commercial Construction Portfolio Segment [Member] | Substandard [Member]
Originated Current Fiscal Year	0		0		0
Originated One Year Prior	0		0		0
Originated Two Years Prior	0		0		0
Originated Three Years Prior	0		0		0
Originated Four Years Prior	0		0		0
Originated Five or More Years Prior	0		0		0
Revolving Loans	2,204		2,204		0
Gross loans	2,204		2,204		0
Commercial Construction Portfolio Segment [Member] | Doubtful [Member]
Originated Current Fiscal Year	0		0		0
Originated One Year Prior	0		0		0
Originated Two Years Prior	0		0		0
Originated Three Years Prior	0		0		0
Originated Four Years Prior	0		0		0
Originated Five or More Years Prior	0		0		0
Revolving Loans	0		0		0
Gross loans	0		0		0
Residential Portfolio Segment [Member]
Originated Current Fiscal Year	11,222		11,222		15,455
Originated One Year Prior	15,126		15,126		42,830
Originated Two Years Prior	41,597		41,597		22,542
Originated Three Years Prior	22,211		22,211		21,704
Originated Four Years Prior	21,004		21,004		19,896
Originated Five or More Years Prior	105,966		105,966		93,909
Revolving Loans	39,660		39,660		39,705
Gross loans	256,786		256,786		256,041
Gross write-off, current year			0		0
Gross write-off, one year prior			0		0
Gross write-off, two years prior			0		0
Gross write-off, three years prior			0		0
Gross write-off, four years prior			0		0
Gross write-off, five years prior			0		0
Gross write-off, revolving			0		18
Gross write-off	(0)	18	0	18	18
Residential Portfolio Segment [Member] | Pass [Member]
Originated Current Fiscal Year	11,222		11,222		15,455
Originated One Year Prior	15,126		15,126		42,830
Originated Two Years Prior	41,597		41,597		21,987
Originated Three Years Prior	21,675		21,675		21,704
Originated Four Years Prior	21,004		21,004		19,896
Originated Five or More Years Prior	104,637		104,637		91,114
Revolving Loans	36,626		36,626		36,082
Gross loans	251,887		251,887		249,068
Residential Portfolio Segment [Member] | Special Mention [Member]
Originated Current Fiscal Year	0		0		0
Originated One Year Prior	0		0		0
Originated Two Years Prior	0		0		0
Originated Three Years Prior	0		0		0
Originated Four Years Prior	0		0		0
Originated Five or More Years Prior	643		643		651
Revolving Loans	2,797		2,797		2,817
Gross loans	3,440		3,440		3,468
Residential Portfolio Segment [Member] | Substandard [Member]
Originated Current Fiscal Year	0		0		0
Originated One Year Prior	0		0		0
Originated Two Years Prior	0		0		555
Originated Three Years Prior	536		536		0
Originated Four Years Prior	0		0		0
Originated Five or More Years Prior	686		686		2,144
Revolving Loans	237		237		806
Gross loans	1,459		1,459		3,505
Residential Portfolio Segment [Member] | Doubtful [Member]
Originated Current Fiscal Year	0		0		0
Originated One Year Prior	0		0		0
Originated Two Years Prior	0		0		0
Originated Three Years Prior	0		0		0
Originated Four Years Prior	0		0		0
Originated Five or More Years Prior	0		0		0
Revolving Loans	0		0		0
Gross loans	0		0		0
Consumer Portfolio Segment [Member]
Originated Current Fiscal Year	809		809		849
Originated One Year Prior	27		27		83
Originated Two Years Prior	10		10		0
Originated Three Years Prior	0		0		5
Originated Four Years Prior	0		0		0
Originated Five or More Years Prior	0		0		0
Revolving Loans	99		99		92
Gross loans	945		945		1,029
Gross write-off, current year			0		0
Gross write-off, one year prior			0		0
Gross write-off, two years prior			0		0
Gross write-off, three years prior			0		0
Gross write-off, four years prior			0		0
Gross write-off, five years prior			0		0
Gross write-off, revolving			0		1
Gross write-off	(0)	$ (0)	0	$ (0)	1
Consumer Portfolio Segment [Member] | Pass [Member]
Originated Current Fiscal Year	809		809		849
Originated One Year Prior	27		27		83
Originated Two Years Prior	10		10		0
Originated Three Years Prior	0		0		5
Originated Four Years Prior	0		0		0
Originated Five or More Years Prior	0		0		0
Revolving Loans	99		99		92
Gross loans	945		945		1,029
Consumer Portfolio Segment [Member] | Special Mention [Member]
Originated Current Fiscal Year	0		0		0
Originated One Year Prior	0		0		0
Originated Two Years Prior	0		0		0
Originated Three Years Prior	0		0		0
Originated Four Years Prior	0		0		0
Originated Five or More Years Prior	0		0		0
Revolving Loans	0		0		0
Gross loans	0		0		0
Consumer Portfolio Segment [Member] | Substandard [Member]
Originated Current Fiscal Year	0		0		0
Originated One Year Prior	0		0		0
Originated Two Years Prior	0		0		0
Originated Three Years Prior	0		0		0
Originated Four Years Prior	0		0		0
Originated Five or More Years Prior	0		0		0
Revolving Loans	0		0		0
Gross loans	0		0		0
Consumer Portfolio Segment [Member] | Doubtful [Member]
Originated Current Fiscal Year	0		0		0
Originated One Year Prior	0		0		0
Originated Two Years Prior	0		0		0
Originated Three Years Prior	0		0		0
Originated Four Years Prior	0		0		0
Originated Five or More Years Prior	0		0		0
Revolving Loans	0		0		0
Gross loans	$ 0		$ 0		$ 0