Allowance for Credit Losses - Schedule of Loan Portfolio by Credit Quality Indicator (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
2024	$ 9,914,841		$ 9,914,841
2023	13,142,424		13,142,424
2022	5,595,328		5,595,328
2021	4,037,517		4,037,517
2020	1,857,010		1,857,010
Prior	4,848,930		4,848,930
Revolving	5,265,665		5,265,665
Revolving to term	13,816		13,816
Total Loans	44,675,531	$ 41,023,408	44,675,531	$ 41,023,408	$ 42,131,831
Gross write offs
2024			244
2023			29,608
2022			3,464
2021			1,220
2020			2,088
Prior			21,973
Revolving			0
Revolving to term			0
Total loans	34,756	18,516	58,597	25,867
Commercial, industrial and other
Financing Receivable, Credit Quality Indicator [Line Items]
2024	1,763,733		1,763,733
2023	2,572,616		2,572,616
2022	1,965,385		1,965,385
2021	1,456,345		1,456,345
2020	556,875		556,875
Prior	1,167,125		1,167,125
Revolving	4,662,020		4,662,020
Revolving to term	10,363		10,363
Total Loans	14,154,462		14,154,462
Construction and development
Financing Receivable, Credit Quality Indicator [Line Items]
2024	78,100		78,100
2023	476,789		476,789
2022	988,979		988,979
2021	389,283		389,283
2020	83,249		83,249
Prior	221,801		221,801
Revolving	22,350		22,350
Revolving to term	0		0
Total Loans	2,260,551		2,260,551
Non-construction
Financing Receivable, Credit Quality Indicator [Line Items]
2024	714,207		714,207
2023	1,528,020		1,528,020
2022	1,809,544		1,809,544
2021	1,416,564		1,416,564
2020	1,001,722		1,001,722
Prior	3,017,337		3,017,337
Revolving	198,987		198,987
Revolving to term	265		265
Total Loans	9,686,646		9,686,646
Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0		0
2023	0		0
2022	837		837
2021	196		196
2020	222		222
Prior	18,294		18,294
Revolving	333,576		333,576
Revolving to term	3,188		3,188
Total Loans	356,313	336,974	356,313	336,974	343,976
Gross write offs
Total loans	0	0	74	0
Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
2024	380,894		380,894
2023	488,777		488,777
2022	825,606		825,606
2021	766,143		766,143
2020	214,473		214,473
Prior	391,442		391,442
Revolving	0		0
Revolving to term	0		0
Total Loans	3,067,335	2,643,240	3,067,335	2,643,240	2,769,666
Gross write offs
Total loans	23	0	61	0
Premium finance receivables - property and casualty
Financing Receivable, Credit Quality Indicator [Line Items]
2024	5,838,783		5,838,783
2023	1,252,957		1,252,957
2022	278		278
2021	8,312		8,312
2020	423		423
Prior	0		0
Revolving	0		0
Revolving to term	0		0
Total Loans	7,100,753		7,100,753
Premium finance receivables - life
Financing Receivable, Credit Quality Indicator [Line Items]
2024	1,137,551		1,137,551
2023	6,820,635		6,820,635
2022	3,929		3,929
2021	0		0
2020	0		0
Prior	0		0
Revolving	0		0
Revolving to term	0		0
Total Loans	7,962,115		7,962,115
Consumer and other
Financing Receivable, Credit Quality Indicator [Line Items]
2024	1,573		1,573
2023	2,630		2,630
2022	770		770
2021	674		674
2020	46		46
Prior	32,931		32,931
Revolving	48,732		48,732
Revolving to term	0		0
Total Loans	87,356	31,941	87,356	31,941	$ 60,500
Gross write offs
Total loans	137	$ 110	244	$ 263
Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2024	9,805,921		9,805,921
2023	12,961,554		12,961,554
2022	5,392,035		5,392,035
2021	3,824,685		3,824,685
2020	1,775,791		1,775,791
Prior	4,442,572		4,442,572
Revolving	5,001,524		5,001,524
Revolving to term	11,968		11,968
Total Loans	43,216,050		43,216,050
Pass | Commercial, industrial and other
Financing Receivable, Credit Quality Indicator [Line Items]
2024	1,759,369		1,759,369
2023	2,462,832		2,462,832
2022	1,847,769		1,847,769
2021	1,330,074		1,330,074
2020	529,579		529,579
Prior	1,099,112		1,099,112
Revolving	4,405,035		4,405,035
Revolving to term	8,966		8,966
Total Loans	13,442,736		13,442,736
Pass | Construction and development
Financing Receivable, Credit Quality Indicator [Line Items]
2024	78,100		78,100
2023	475,118		475,118
2022	973,989		973,989
2021	371,090		371,090
2020	79,439		79,439
Prior	159,686		159,686
Revolving	22,350		22,350
Revolving to term	0		0
Total Loans	2,159,772		2,159,772
Pass | Non-construction
Financing Receivable, Credit Quality Indicator [Line Items]
2024	710,843		710,843
2023	1,515,024		1,515,024
2022	1,757,491		1,757,491
2021	1,360,084		1,360,084
2020	961,509		961,509
Prior	2,884,404		2,884,404
Revolving	198,713		198,713
Revolving to term	265		265
Total Loans	9,388,333		9,388,333
Pass | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0		0
2023	0		0
2022	0		0
2021	0		0
2020	0		0
Prior	9,272		9,272
Revolving	326,705		326,705
Revolving to term	2,737		2,737
Total Loans	338,714		338,714
Pass | Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
2024	380,670		380,670
2023	480,911		480,911
2022	808,108		808,108
2021	754,489		754,489
2020	204,797		204,797
Prior	257,334		257,334
Revolving	0		0
Revolving to term	0		0
Total Loans	2,886,309		2,886,309
Pass | Premium finance receivables - property and casualty
Financing Receivable, Credit Quality Indicator [Line Items]
2024	5,737,826		5,737,826
2023	1,204,432		1,204,432
2022	0		0
2021	8,281		8,281
2020	421		421
Prior	0		0
Revolving	0		0
Revolving to term	0		0
Total Loans	6,950,960		6,950,960
Pass | Premium finance receivables - life
Financing Receivable, Credit Quality Indicator [Line Items]
2024	1,137,551		1,137,551
2023	6,820,635		6,820,635
2022	3,929		3,929
2021	0		0
2020	0		0
Prior	0		0
Revolving	0		0
Revolving to term	0		0
Total Loans	7,962,115		7,962,115
Pass | Consumer and other
Financing Receivable, Credit Quality Indicator [Line Items]
2024	1,562		1,562
2023	2,602		2,602
2022	749		749
2021	667		667
2020	46		46
Prior	32,764		32,764
Revolving	48,721		48,721
Revolving to term	0		0
Total Loans	87,111		87,111
Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
2024	97,305		97,305
2023	94,356		94,356
2022	127,893		127,893
2021	130,213		130,213
2020	24,987		24,987
Prior	121,946		121,946
Revolving	136,488		136,488
Revolving to term	1,587		1,587
Total Loans	734,775		734,775
Special mention | Commercial, industrial and other
Financing Receivable, Credit Quality Indicator [Line Items]
2024	1,704		1,704
2023	62,567		62,567
2022	69,016		69,016
2021	64,001		64,001
2020	6,033		6,033
Prior	51,135		51,135
Revolving	129,899		129,899
Revolving to term	1,300		1,300
Total Loans	385,655		385,655
Special mention | Construction and development
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0		0
2023	1,176		1,176
2022	14,990		14,990
2021	17,091		17,091
2020	0		0
Prior	14,969		14,969
Revolving	0		0
Revolving to term	0		0
Total Loans	48,226		48,226
Special mention | Non-construction
Financing Receivable, Credit Quality Indicator [Line Items]
2024	3,364		3,364
2023	8,422		8,422
2022	37,904		37,904
2021	46,765		46,765
2020	17,230		17,230
Prior	46,738		46,738
Revolving	274		274
Revolving to term	0		0
Total Loans	160,697		160,697
Special mention | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0		0
2023	0		0
2022	222		222
2021	59		59
2020	120		120
Prior	2,417		2,417
Revolving	6,313		6,313
Revolving to term	287		287
Total Loans	9,418		9,418
Special mention | Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0		0
2023	2,985		2,985
2022	5,655		5,655
2021	2,284		2,284
2020	1,604		1,604
Prior	6,547		6,547
Revolving	0		0
Revolving to term	0		0
Total Loans	19,075		19,075
Special mention | Premium finance receivables - property and casualty
Financing Receivable, Credit Quality Indicator [Line Items]
2024	92,231		92,231
2023	19,192		19,192
2022	95		95
2021	8		8
2020	0		0
Prior	0		0
Revolving	0		0
Revolving to term	0		0
Total Loans	111,526		111,526
Special mention | Premium finance receivables - life
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0		0
2023	0		0
2022	0		0
2021	0		0
2020	0		0
Prior	0		0
Revolving	0		0
Revolving to term	0		0
Total Loans	0		0
Special mention | Consumer and other
Financing Receivable, Credit Quality Indicator [Line Items]
2024	6		6
2023	14		14
2022	11		11
2021	5		5
2020	0		0
Prior	140		140
Revolving	2		2
Revolving to term	0		0
Total Loans	178		178
Substandard accrual
Financing Receivable, Credit Quality Indicator [Line Items]
2024	4,377		4,377
2023	49,131		49,131
2022	60,045		60,045
2021	51,885		51,885
2020	46,031		46,031
Prior	107,891		107,891
Revolving	119,677		119,677
Revolving to term	92		92
Total Loans	439,129		439,129
Substandard accrual | Commercial, industrial and other
Financing Receivable, Credit Quality Indicator [Line Items]
2024	2,660		2,660
2023	41,267		41,267
2022	42,882		42,882
2021	40,319		40,319
2020	20,026		20,026
Prior	8,703		8,703
Revolving	119,110		119,110
Revolving to term	17		17
Total Loans	274,984		274,984
Substandard accrual | Construction and development
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0		0
2023	0		0
2022	0		0
2021	1,102		1,102
2020	1,777		1,777
Prior	47,146		47,146
Revolving	0		0
Revolving to term	0		0
Total Loans	50,025		50,025
Substandard accrual | Non-construction
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0		0
2023	3,202		3,202
2022	13,696		13,696
2021	9,545		9,545
2020	22,983		22,983
Prior	42,429		42,429
Revolving	0		0
Revolving to term	0		0
Total Loans	91,855		91,855
Substandard accrual | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0		0
2023	0		0
2022	104		104
2021	0		0
2020	102		102
Prior	6,242		6,242
Revolving	558		558
Revolving to term	75		75
Total Loans	7,081		7,081
Substandard accrual | Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
2024	224		224
2023	596		596
2022	3,353		3,353
2021	915		915
2020	1,143		1,143
Prior	3,344		3,344
Revolving	0		0
Revolving to term	0		0
Total Loans	9,575		9,575
Substandard accrual | Premium finance receivables - property and casualty
Financing Receivable, Credit Quality Indicator [Line Items]
2024	1,488		1,488
2023	4,052		4,052
2022	1		1
2021	4		4
2020	0		0
Prior	0		0
Revolving	0		0
Revolving to term	0		0
Total Loans	5,545		5,545
Substandard accrual | Premium finance receivables - life
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0		0
2023	0		0
2022	0		0
2021	0		0
2020	0		0
Prior	0		0
Revolving	0		0
Revolving to term	0		0
Total Loans	0		0
Substandard accrual | Consumer and other
Financing Receivable, Credit Quality Indicator [Line Items]
2024	5		5
2023	14		14
2022	9		9
2021	0		0
2020	0		0
Prior	27		27
Revolving	9		9
Revolving to term	0		0
Total Loans	64		64
Substandard nonaccrual/doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
2024	7,238		7,238
2023	33,621		33,621
2022	11,974		11,974
2021	26,921		26,921
2020	4,501		4,501
Prior	58,999		58,999
Revolving	7,976		7,976
Revolving to term	169		169
Total Loans	151,399		151,399
Substandard nonaccrual/doubtful | Commercial, industrial and other
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0		0
2023	5,950		5,950
2022	5,718		5,718
2021	21,951		21,951
2020	1,237		1,237
Prior	8,175		8,175
Revolving	7,976		7,976
Revolving to term	80		80
Total Loans	51,087		51,087
Substandard nonaccrual/doubtful | Construction and development
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0		0
2023	495		495
2022	0		0
2021	0		0
2020	2,033		2,033
Prior	0		0
Revolving	0		0
Revolving to term	0		0
Total Loans	2,528		2,528
Substandard nonaccrual/doubtful | Non-construction
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0		0
2023	1,372		1,372
2022	453		453
2021	170		170
2020	0		0
Prior	43,766		43,766
Revolving	0		0
Revolving to term	0		0
Total Loans	45,761		45,761
Substandard nonaccrual/doubtful | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0		0
2023	0		0
2022	511		511
2021	137		137
2020	0		0
Prior	363		363
Revolving	0		0
Revolving to term	89		89
Total Loans	1,100		1,100
Substandard nonaccrual/doubtful | Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0		0
2023	523		523
2022	5,109		5,109
2021	4,642		4,642
2020	1,229		1,229
Prior	6,695		6,695
Revolving	0		0
Revolving to term	0		0
Total Loans	18,198		18,198
Substandard nonaccrual/doubtful | Premium finance receivables - property and casualty
Financing Receivable, Credit Quality Indicator [Line Items]
2024	7,238		7,238
2023	25,281		25,281
2022	182		182
2021	19		19
2020	2		2
Prior	0		0
Revolving	0		0
Revolving to term	0		0
Total Loans	32,722		32,722
Substandard nonaccrual/doubtful | Premium finance receivables - life
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0		0
2023	0		0
2022	0		0
2021	0		0
2020	0		0
Prior	0		0
Revolving	0		0
Revolving to term	0		0
Total Loans	0		0
Substandard nonaccrual/doubtful | Consumer and other
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0		0
2023	0		0
2022	1		1
2021	2		2
2020	0		0
Prior	0		0
Revolving	0		0
Revolving to term	0		0
Total Loans	3		3
Early buy-out loans guaranteed by U.S. government agencies
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0		0
2023	3,762		3,762
2022	3,381		3,381
2021	3,813		3,813
2020	5,700		5,700
Prior	117,522		117,522
Revolving	0		0
Revolving to term	0		0
Total Loans	134,178		134,178
Early buy-out loans guaranteed by U.S. government agencies | Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0		0
2023	3,762		3,762
2022	3,381		3,381
2021	3,813		3,813
2020	5,700		5,700
Prior	117,522		117,522
Revolving	0		0
Revolving to term	0		0
Total Loans	$ 134,178		$ 134,178