Allowance for Credit Losses - Schedule of Loan Portfolio by Credit Quality Indicator (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022
Financing Receivable, Credit Quality Indicator [Line Items]
2023	$ 12,447,080	$ 12,447,080
2022	6,481,150	6,481,150
2021	5,201,099	5,201,099
2020	3,130,812	3,130,812
2019	2,345,897	2,345,897
Prior	7,873,495	7,873,495
Revolving	4,635,248	4,635,248
Revolving to Term	17,050	17,050
Total Loans	42,131,831	42,131,831	$ 39,196,485
Gross write offs
2023	7,318	19,044
2022	1,853	10,204
2021	1,566	4,340
2020	5,825	11,356
2019	762	6,444
Prior	144	2,424
Revolving	0	0
Revolving to Term	0	0
Total loans	17,468	53,812	31,779
Commercial, industrial and other
Financing Receivable, Credit Quality Indicator [Line Items]
2023	2,835,388	2,835,388
2022	2,245,714	2,245,714
2021	1,647,896	1,647,896
2020	673,967	673,967
2019	377,516	377,516
Prior	985,191	985,191
Revolving	4,056,505	4,056,505
Revolving to Term	9,876	9,876
Total Loans	12,832,053	12,832,053
Construction and development
Financing Receivable, Credit Quality Indicator [Line Items]
2023	335,772	335,772
2022	853,973	853,973
2021	461,880	461,880
2020	165,400	165,400
2019	134,827	134,827
Prior	109,609	109,609
Revolving	22,219	22,219
Revolving to Term	361	361
Total Loans	2,084,041	2,084,041
Non-construction
Financing Receivable, Credit Quality Indicator [Line Items]
2023	1,513,039	1,513,039
2022	1,851,046	1,851,046
2021	1,408,235	1,408,235
2020	995,698	995,698
2019	794,926	794,926
Prior	2,504,544	2,504,544
Revolving	188,998	188,998
Revolving to Term	3,637	3,637
Total Loans	9,260,123	9,260,123
Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0	0
2022	568	568
2021	140	140
2020	155	155
2019	175	175
Prior	14,766	14,766
Revolving	324,996	324,996
Revolving to Term	3,176	3,176
Total Loans	343,976	343,976	332,698
Gross write offs
Total loans		227	432
Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
2023	474,623	474,623
2022	849,281	849,281
2021	788,786	788,786
2020	225,842	225,842
2019	127,161	127,161
Prior	303,973	303,973
Revolving	0	0
Revolving to Term	0	0
Total Loans	2,769,666	2,769,666	2,372,383
Gross write offs
Total loans		192	471
Premium finance receivables - property & casualty
Financing Receivable, Credit Quality Indicator [Line Items]
2023	6,880,952	6,880,952
2022	5,422	5,422
2021	15,278	15,278
2020	1,876	1,876
2019	1	1
Prior	0	0
Revolving	0	0
Revolving to Term	0	0
Total Loans	6,903,529	6,903,529
Premium finance receivables - life
Financing Receivable, Credit Quality Indicator [Line Items]
2023	403,756	403,756
2022	673,757	673,757
2021	878,027	878,027
2020	1,067,781	1,067,781
2019	910,951	910,951
Prior	3,943,671	3,943,671
Revolving	0	0
Revolving to Term	0	0
Total Loans	7,877,943	7,877,943
Consumer and other
Financing Receivable, Credit Quality Indicator [Line Items]
2023	3,550	3,550
2022	1,389	1,389
2021	857	857
2020	93	93
2019	340	340
Prior	11,741	11,741
Revolving	42,530	42,530
Revolving to Term	0	0
Total Loans	60,500	60,500	50,836
Gross write offs
Total loans		595	$ 1,081
Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2023	12,233,294	12,233,294
2022	6,322,168	6,322,168
2021	5,011,350	5,011,350
2020	3,051,097	3,051,097
2019	2,204,172	2,204,172
Prior	7,521,444	7,521,444
Revolving	4,424,648	4,424,648
Revolving to Term	12,252	12,252
Total Loans	40,780,425	40,780,425
Pass \| Commercial, industrial and other
Financing Receivable, Credit Quality Indicator [Line Items]
2023	2,759,782	2,759,782
2022	2,130,216	2,130,216
2021	1,533,575	1,533,575
2020	649,008	649,008
2019	352,589	352,589
Prior	933,178	933,178
Revolving	3,849,975	3,849,975
Revolving to Term	7,517	7,517
Total Loans	12,215,840	12,215,840
Pass \| Construction and development
Financing Receivable, Credit Quality Indicator [Line Items]
2023	335,521	335,521
2022	851,469	851,469
2021	443,239	443,239
2020	163,025	163,025
2019	85,644	85,644
Prior	83,050	83,050
Revolving	22,219	22,219
Revolving to Term	361	361
Total Loans	1,984,528	1,984,528
Pass \| Non-construction
Financing Receivable, Credit Quality Indicator [Line Items]
2023	1,501,555	1,501,555
2022	1,828,359	1,828,359
2021	1,363,081	1,363,081
2020	954,632	954,632
2019	745,089	745,089
Prior	2,373,611	2,373,611
Revolving	188,998	188,998
Revolving to Term	2,202	2,202
Total Loans	8,957,527	8,957,527
Pass \| Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0	0
2022	57	57
2021	0	0
2020	45	45
2019	92	92
Prior	6,416	6,416
Revolving	320,941	320,941
Revolving to Term	2,172	2,172
Total Loans	329,723	329,723
Pass \| Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
2023	470,659	470,659
2022	836,948	836,948
2021	777,456	777,456
2020	214,640	214,640
2019	109,466	109,466
Prior	169,888	169,888
Revolving	0	0
Revolving to Term	0	0
Total Loans	2,579,057	2,579,057
Pass \| Premium finance receivables - property & casualty
Financing Receivable, Credit Quality Indicator [Line Items]
2023	6,758,490	6,758,490
2022	0	0
2021	15,119	15,119
2020	1,873	1,873
2019	1	1
Prior	0	0
Revolving	0	0
Revolving to Term	0	0
Total Loans	6,775,483	6,775,483
Pass \| Premium finance receivables - life
Financing Receivable, Credit Quality Indicator [Line Items]
2023	403,756	403,756
2022	673,757	673,757
2021	878,027	878,027
2020	1,067,781	1,067,781
2019	910,951	910,951
Prior	3,943,671	3,943,671
Revolving	0	0
Revolving to Term	0	0
Total Loans	7,877,943	7,877,943
Pass \| Consumer and other
Financing Receivable, Credit Quality Indicator [Line Items]
2023	3,531	3,531
2022	1,362	1,362
2021	853	853
2020	93	93
2019	340	340
Prior	11,630	11,630
Revolving	42,515	42,515
Revolving to Term	0	0
Total Loans	60,324	60,324
Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
2023	139,521	139,521
2022	91,056	91,056
2021	147,259	147,259
2020	38,598	38,598
2019	38,711	38,711
Prior	55,316	55,316
Revolving	104,842	104,842
Revolving to Term	2,855	2,855
Total Loans	618,158	618,158
Special mention \| Commercial, industrial and other
Financing Receivable, Credit Quality Indicator [Line Items]
2023	31,825	31,825
2022	66,245	66,245
2021	85,651	85,651
2020	17,690	17,690
2019	15,412	15,412
Prior	7,022	7,022
Revolving	101,925	101,925
Revolving to Term	1,420	1,420
Total Loans	327,190	327,190
Special mention \| Construction and development
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0	0
2022	0	0
2021	18,641	18,641
2020	0	0
2019	0	0
Prior	180	180
Revolving	0	0
Revolving to Term	0	0
Total Loans	18,821	18,821
Special mention \| Non-construction
Financing Receivable, Credit Quality Indicator [Line Items]
2023	9,343	9,343
2022	20,721	20,721
2021	41,766	41,766
2020	19,585	19,585
2019	22,496	22,496
Prior	41,796	41,796
Revolving	0	0
Revolving to Term	1,435	1,435
Total Loans	157,142	157,142
Special mention \| Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0	0
2022	225	225
2021	63	63
2020	0	0
2019	67	67
Prior	1,667	1,667
Revolving	2,914	2,914
Revolving to Term	0	0
Total Loans	4,936	4,936
Special mention \| Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
2023	1,470	1,470
2022	3,541	3,541
2021	1,036	1,036
2020	1,323	1,323
2019	736	736
Prior	4,572	4,572
Revolving	0	0
Revolving to Term	0	0
Total Loans	12,678	12,678
Special mention \| Premium finance receivables - property & casualty
Financing Receivable, Credit Quality Indicator [Line Items]
2023	96,875	96,875
2022	314	314
2021	102	102
2020	0	0
2019	0	0
Prior	0	0
Revolving	0	0
Revolving to Term	0	0
Total Loans	97,291	97,291
Special mention \| Premium finance receivables - life
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0	0
2022	0	0
2021	0	0
2020	0	0
2019	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]
2023	8	8
2022	10	10
2021	0	0
2020	0	0
2019	0	0
Prior	79	79
Revolving	3	3
Revolving to Term	0	0
Total Loans	100	100
Substandard accrual
Financing Receivable, Credit Quality Indicator [Line Items]
2023	35,390	35,390
2022	50,061	50,061
2021	27,318	27,318
2020	28,581	28,581
2019	84,614	84,614
Prior	131,688	131,688
Revolving	104,465	104,465
Revolving to Term	1,805	1,805
Total Loans	463,922	463,922
Substandard accrual \| Commercial, industrial and other
Financing Receivable, Credit Quality Indicator [Line Items]
2023	30,484	30,484
2022	41,655	41,655
2021	23,049	23,049
2020	4,469	4,469
2019	8,005	8,005
Prior	38,125	38,125
Revolving	103,405	103,405
Revolving to Term	891	891
Total Loans	250,083	250,083
Substandard accrual \| Construction and development
Financing Receivable, Credit Quality Indicator [Line Items]
2023	251	251
2022	2,504	2,504
2021	0	0
2020	2,375	2,375
2019	49,183	49,183
Prior	24,174	24,174
Revolving	0	0
Revolving to Term	0	0
Total Loans	78,487	78,487
Substandard accrual \| Non-construction
Financing Receivable, Credit Quality Indicator [Line Items]
2023	1,189	1,189
2022	1,462	1,462
2021	3,005	3,005
2020	20,696	20,696
2019	26,954	26,954
Prior	58,894	58,894
Revolving	0	0
Revolving to Term	0	0
Total Loans	112,200	112,200
Substandard accrual \| Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0	0
2022	105	105
2021	0	0
2020	0	0
2019	0	0
Prior	5,909	5,909
Revolving	1,048	1,048
Revolving to Term	914	914
Total Loans	7,976	7,976
Substandard accrual \| Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
2023	924	924
2022	3,706	3,706
2021	1,261	1,261
2020	1,040	1,040
2019	472	472
Prior	4,554	4,554
Revolving	0	0
Revolving to Term	0	0
Total Loans	11,957	11,957
Substandard accrual \| Premium finance receivables - property & casualty
Financing Receivable, Credit Quality Indicator [Line Items]
2023	2,540	2,540
2022	621	621
2021	3	3
2020	1	1
2019	0	0
Prior	0	0
Revolving	0	0
Revolving to Term	0	0
Total Loans	3,165	3,165
Substandard accrual \| Premium finance receivables - life
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0	0
2022	0	0
2021	0	0
2020	0	0
2019	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]
2023	2	2
2022	8	8
2021	0	0
2020	0	0
2019	0	0
Prior	32	32
Revolving	12	12
Revolving to Term	0	0
Total Loans	54	54
Substandard nonaccrual/doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
2023	37,405	37,405
2022	15,059	15,059
2021	10,656	10,656
2020	4,502	4,502
2019	3,420	3,420
Prior	46,270	46,270
Revolving	1,293	1,293
Revolving to Term	138	138
Total Loans	118,743	118,743
Substandard nonaccrual/doubtful \| Commercial, industrial and other
Financing Receivable, Credit Quality Indicator [Line Items]
2023	13,297	13,297
2022	7,598	7,598
2021	5,621	5,621
2020	2,800	2,800
2019	1,510	1,510
Prior	6,866	6,866
Revolving	1,200	1,200
Revolving to Term	48	48
Total Loans	38,940	38,940
Substandard nonaccrual/doubtful \| Construction and development
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0	0
2022	0	0
2021	0	0
2020	0	0
2019	0	0
Prior	2,205	2,205
Revolving	0	0
Revolving to Term	0	0
Total Loans	2,205	2,205
Substandard nonaccrual/doubtful \| Non-construction
Financing Receivable, Credit Quality Indicator [Line Items]
2023	952	952
2022	504	504
2021	383	383
2020	785	785
2019	387	387
Prior	30,243	30,243
Revolving	0	0
Revolving to Term	0	0
Total Loans	33,254	33,254
Substandard nonaccrual/doubtful \| Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0	0
2022	181	181
2021	77	77
2020	110	110
2019	16	16
Prior	774	774
Revolving	93	93
Revolving to Term	90	90
Total Loans	1,341	1,341
Substandard nonaccrual/doubtful \| Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
2023	100	100
2022	2,280	2,280
2021	4,517	4,517
2020	805	805
2019	1,507	1,507
Prior	6,182	6,182
Revolving	0	0
Revolving to Term	0	0
Total Loans	15,391	15,391
Substandard nonaccrual/doubtful \| Premium finance receivables - property & casualty
Financing Receivable, Credit Quality Indicator [Line Items]
2023	23,047	23,047
2022	4,487	4,487
2021	54	54
2020	2	2
2019	0	0
Prior	0	0
Revolving	0	0
Revolving to Term	0	0
Total Loans	27,590	27,590
Substandard nonaccrual/doubtful \| Premium finance receivables - life
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0	0
2022	0	0
2021	0	0
2020	0	0
2019	0	0
Prior	0	0
Revolving	0	0
Revolving to Term	0	0
Total Loans	0	0

Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-6

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-13