Note 5 - Loans - Loan Held for Investment by Loan Portfolio Segments, Internal Risk Ratings and Vintage Year (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025	Dec. 31, 2025
Originated current year	$ 3,040,953		$ 3,040,953		$ 3,411,331
Originated prior year	3,228,559		3,228,559		2,146,605
Originated two years prior	1,784,156		1,784,156		2,947,859
Originated three years prior	2,550,572		2,550,572		2,725,330
Originated four years prior	2,456,555		2,456,555		2,297,334
Originated years prior	5,342,806		5,342,806		4,255,068
Revolving	2,751,675		2,751,675		2,323,975
Converted to Term	25,062		25,062		24,797
Loans	21,180,338		21,180,338		20,132,299
Current year, write offs			0		0
Prior year, write offs			74		249
Two years prior, write offs			2,232		715
Three years prior, write offs			325		2,752
Four years prior, write offs			11,014		5,399
Years prior, write offs			22,093		16,135
Revolving, write offs			3,308		12,487
Converted to term, write offs			0		0
Loans, write offs	26,947	$ 16,487	39,046	$ 31,861	37,737
Doubtful	21,180,338		21,180,338		20,132,299
Commercial Portfolio Segment [Member]
Originated current year	519,125		519,125		400,479
Originated prior year	400,855		400,855		226,310
Originated two years prior	173,942		173,942		237,136
Originated three years prior	192,754		192,754		160,611
Originated four years prior	152,278		152,278		165,594
Originated years prior	216,481		216,481		100,473
Revolving	2,277,874		2,277,874		1,881,850
Converted to Term	8,378		8,378		7,300
Loans	3,941,687		3,941,687		3,179,753
Current year, write offs			0		0
Prior year, write offs			74		175
Two years prior, write offs			2,232		715
Three years prior, write offs			309		2,752
Four years prior, write offs			2,204		4,469
Years prior, write offs			2,848		12,503
Revolving, write offs			3,308		12,487
Converted to term, write offs			0		0
Loans, write offs	261	16,173	10,975	27,634	33,101
Doubtful	3,941,687		3,941,687		3,179,753
Commercial Portfolio Segment [Member] | Pass [Member]
Originated current year	517,548		517,548		384,065
Originated prior year	376,222		376,222		190,685
Originated two years prior	169,974		169,974		220,174
Originated three years prior	177,681		177,681		154,865
Originated four years prior	149,358		149,358		157,979
Originated years prior	200,911		200,911		85,858
Revolving	2,216,913		2,216,913		1,702,322
Converted to Term	7,451		7,451		6,269
Loans	3,816,058		3,816,058		2,902,217
Doubtful	3,816,058		3,816,058		2,902,217
Commercial Portfolio Segment [Member] | Special Mention [Member]
Originated current year	1,547		1,547		0
Originated prior year	13,074		13,074		33,459
Originated two years prior	3,968		3,968		0
Originated three years prior	2,094		2,094		1,462
Originated four years prior	1,032		1,032		5,000
Originated years prior	3,664		3,664		3,875
Revolving	37,435		37,435		117,738
Converted to Term	0		0		0
Loans	62,814		62,814		161,534
Doubtful	62,814		62,814		161,534
Commercial Portfolio Segment [Member] | Substandard [Member]
Originated current year	30		30		16,414
Originated prior year	11,559		11,559		2,166
Originated two years prior	0		0		16,962
Originated three years prior	12,979		12,979		2,479
Originated four years prior	1,888		1,888		2,615
Originated years prior	11,906		11,906		10,443
Revolving	23,526		23,526		61,790
Converted to Term	927		927		1,031
Loans	62,815		62,815		113,900
Doubtful	62,815		62,815		113,900
Commercial Portfolio Segment [Member] | Doubtful [Member]
Originated current year					0
Originated prior year					0
Originated two years prior					0
Originated three years prior					1,805
Originated four years prior					0
Originated years prior					297
Revolving					0
Converted to Term					0
Loans					2,102
Doubtful					2,102
Real Estate Construction Portfolio Segment [Member]
Originated current year	60,757		60,757		86,893
Originated prior year	109,294		109,294		69,113
Originated two years prior	29,745		29,745		47,036
Originated three years prior	33,281		33,281		68,635
Originated four years prior	0		0		56,343
Originated years prior	28,383		28,383		6,636
Revolving	2,346		2,346		1,298
Converted to Term	0		0		0
Loans	263,806		263,806		335,954
Current year, write offs			0		0
Prior year, write offs			0		0
Two years prior, write offs			0		0
Three years prior, write offs			0		0
Four years prior, write offs			8,810		0
Years prior, write offs			0		0
Revolving, write offs			0		0
Converted to term, write offs			0		0
Loans, write offs	8,810	(0)	8,810	(0)	0
Doubtful	263,806		263,806		335,954
Real Estate Construction Portfolio Segment [Member] | Pass [Member]
Originated current year	52,643		52,643		86,893
Originated prior year	109,294		109,294		69,113
Originated two years prior	29,745		29,745		37,801
Originated three years prior	28,464		28,464		68,635
Originated four years prior	0		0		30,283
Originated years prior	24,563		24,563		0
Revolving	2,346		2,346		1,298
Converted to Term	0		0		0
Loans	247,055		247,055		294,023
Doubtful	247,055		247,055		294,023
Real Estate Construction Portfolio Segment [Member] | Special Mention [Member]
Originated current year	32,672		32,672		0
Originated prior year	16,254		16,254		0
Originated two years prior	34,137		34,137		9,235
Originated three years prior	81,108		81,108		0
Originated four years prior	103,403		103,403		0
Originated years prior	51,386		51,386		0
Revolving	8,600		8,600		0
Converted to Term	0		0		0
Loans	327,560		327,560		9,235
Doubtful	327,560		327,560		9,235
Real Estate Construction Portfolio Segment [Member] | Substandard [Member]
Originated current year	8,114		8,114		0
Originated prior year	0		0		0
Originated two years prior	0		0		0
Originated three years prior	4,817		4,817		0
Originated four years prior	0		0		26,060
Originated years prior	3,820		3,820		6,636
Revolving	0		0		0
Converted to Term	0		0		0
Loans	16,751		16,751		32,696
Doubtful	16,751		16,751		32,696
Commercial Real Estate Portfolio Segment [Member]
Originated current year	1,627,614		1,627,614		1,941,874
Originated prior year	1,864,149		1,864,149		1,360,416
Originated two years prior	1,209,703		1,209,703		1,758,888
Originated three years prior	1,543,804		1,543,804		1,582,709
Originated four years prior	1,480,690		1,480,690		1,382,164
Originated years prior	2,850,984		2,850,984		2,298,683
Revolving	259,286		259,286		230,077
Converted to Term	513		513		1,208
Loans	10,836,743		10,836,743		10,556,019
Current year, write offs			0		0
Prior year, write offs			0		0
Two years prior, write offs			0		0
Three years prior, write offs			0		0
Four years prior, write offs			0		930
Years prior, write offs			19,245		3,632
Revolving, write offs			0		0
Converted to term, write offs			0		0
Loans, write offs	17,876	314	19,245	4,153	4,562
Doubtful	10,836,743		10,836,743		10,556,019
Commercial Real Estate Portfolio Segment [Member] | Pass [Member]
Originated current year	1,592,518		1,592,518		1,909,540
Originated prior year	1,845,735		1,845,735		1,286,856
Originated two years prior	1,138,664		1,138,664		1,673,226
Originated three years prior	1,438,120		1,438,120		1,442,872
Originated four years prior	1,317,854		1,317,854		1,290,175
Originated years prior	2,688,482		2,688,482		2,184,774
Revolving	250,295		250,295		206,139
Converted to Term	513		513		0
Loans	10,272,181		10,272,181		9,993,582
Doubtful	10,272,181		10,272,181		9,993,582
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member]
Originated current year	0		0		29,745
Originated prior year	0		0		58,491
Originated two years prior	0		0		74,142
Originated three years prior	0		0		113,065
Originated four years prior	0		0		32,074
Originated years prior	1,532		1,532		33,062
Revolving	0		0		22,214
Converted to Term	0		0		0
Loans	1,532		1,532		362,793
Doubtful	1,532		1,532		362,793
Commercial Real Estate Portfolio Segment [Member] | Substandard [Member]
Originated current year	2,424		2,424		2,589
Originated prior year	2,160		2,160		15,069
Originated two years prior	36,902		36,902		11,520
Originated three years prior	24,576		24,576		26,772
Originated four years prior	59,433		59,433		59,915
Originated years prior	111,116		111,116		63,004
Revolving	391		391		1,724
Converted to Term	0		0		1,208
Loans	237,002		237,002		181,801
Doubtful	237,002		237,002		181,801
Commercial Real Estate Portfolio Segment [Member] | Doubtful [Member]
Originated current year					0
Originated prior year					0
Originated two years prior					0
Originated three years prior					0
Originated four years prior					0
Originated years prior					17,843
Revolving					0
Converted to Term					0
Loans					17,843
Doubtful					17,843
Residential Portfolio Segment [Member]
Originated current year	827,532		827,532		980,450
Originated prior year	853,698		853,698		490,658
Originated two years prior	370,766		370,766		904,799
Originated three years prior	780,733		780,733		913,304
Originated four years prior	823,525		823,525		693,233
Originated years prior	2,246,958		2,246,958		1,849,276
Revolving	0		0		0
Converted to Term	0		0		0
Loans	5,903,212		5,903,212		5,831,720
Current year, write offs			0		0
Prior year, write offs			0		74
Two years prior, write offs			0		0
Three years prior, write offs			16		0
Four years prior, write offs			0		0
Years prior, write offs			0		0
Revolving, write offs			0		0
Converted to term, write offs			0		0
Loans, write offs			16		74
Doubtful	5,903,212		5,903,212		5,831,720
Residential Portfolio Segment [Member] | Pass [Member]
Originated current year	827,519		827,519		980,403
Originated prior year	849,858		849,858		488,518
Originated two years prior	367,606		367,606		899,547
Originated three years prior	774,598		774,598		905,719
Originated four years prior	813,731		813,731		688,469
Originated years prior	2,218,478		2,218,478		1,826,904
Revolving	0		0		0
Converted to Term	0		0		0
Loans	5,851,790		5,851,790		5,789,560
Doubtful	5,851,790		5,851,790		5,789,560
Residential Portfolio Segment [Member] | Special Mention [Member]
Originated current year					0
Originated prior year					0
Originated two years prior					0
Originated three years prior					0
Originated four years prior					0
Originated years prior					1,571
Revolving					0
Converted to Term					0
Loans					1,571
Doubtful					1,571
Residential Portfolio Segment [Member] | Substandard [Member]
Originated current year	13		13		47
Originated prior year	3,840		3,840		2,140
Originated two years prior	3,160		3,160		5,252
Originated three years prior	6,135		6,135		7,585
Originated four years prior	9,794		9,794		4,764
Originated years prior	26,948		26,948		20,801
Revolving	0		0		0
Converted to Term	0		0		0
Loans	49,890		49,890		40,589
Doubtful	49,890		49,890		40,589
Equity Lines Portfolio Segment [Member]
Originated current year	0		0		0
Originated prior year	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 years prior	0		0		0
Revolving	212,169		212,169		210,750
Converted to Term	16,171		16,171		16,289
Loans	228,340		228,340		227,039
Current year, write offs			0		0
Prior year, write offs			0		0
Two years prior, write offs			0		0
Three years prior, write offs			0		0
Four years prior, write offs			0		0
Years prior, write offs			0		0
Revolving, write offs			0		0
Converted to term, write offs			0		0
Loans, write offs			0		0
Doubtful	228,340		228,340		227,039
Equity Lines Portfolio Segment [Member] | Pass [Member]
Originated current year	0		0		0
Originated prior year	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 years prior	0		0		0
Revolving	211,285		211,285		209,256
Converted to Term	15,923		15,923		15,853
Loans	227,208		227,208		225,109
Doubtful	227,208		227,208		225,109
Equity Lines Portfolio Segment [Member] | Substandard [Member]
Originated current year	0		0		0
Originated prior year	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 years prior	0		0		0
Revolving	884		884		1,494
Converted to Term	248		248		436
Loans	1,132		1,132		1,930
Doubtful	1,132		1,132		1,930
Installment and Other Loans [Member ]
Originated current year	5,925		5,925		1,635
Originated prior year	563		563		108
Originated two years prior	0		0		0
Originated three years prior	0		0		71
Originated four years prior	62		62		0
Originated years prior	0		0		0
Revolving	0		0		0
Converted to Term	0		0		0
Loans	6,550		6,550		1,814
Current year, write offs			0		0
Prior year, write offs			0		0
Two years prior, write offs			0		0
Three years prior, write offs			0		0
Four years prior, write offs			0		0
Years prior, write offs			0		0
Revolving, write offs			0		0
Converted to term, write offs			0		0
Loans, write offs	(0)	$ (0)	0	$ (0)	0
Doubtful	6,550		6,550		1,814
Installment and Other Loans [Member ] | Pass [Member]
Originated current year	5,925		5,925		1,635
Originated prior year	563		563		108
Originated two years prior	0		0		0
Originated three years prior	0		0		71
Originated four years prior	62		62		0
Originated years prior	0		0		0
Revolving	0		0		0
Converted to Term	0		0		0
Loans	6,550		6,550		1,814
Doubtful	$ 6,550		$ 6,550		$ 1,814