Loans Past Due Status (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2023	Dec. 31, 2022
Summarized details of Loans
Current	$ 29,975,051	$ 29,975,051	$ 28,652,257
Financing Receivable, Nonaccrual	168,558	168,558	111,467
Loans and Leases Receivable, Net of Deferred Income, Total	30,193,187	30,193,187	28,799,569
Nonaccrual Loans, Current Portion	$ 114,000	$ 114,000	$ 64,000
Percent of current nonaccrual loans	68.00%	68.00%	58.00%
Financing Receivable, Nonaccrual, Interest Income	$ 0	$ 0	$ 0
Financing Receivable, Nonaccrual, No Allowance	65,000	65,000	11,000
30-59 Days Past Due
Summarized details of Loans
Total Past Due	42,797	42,797	26,256
60-89 Days Past Due
Summarized details of Loans
Total Past Due	4,626	4,626	7,861
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	2,156	2,156	1,728
Commercial and Industrial Sector
Summarized details of Loans
Current	10,022,308	10,022,308	9,738,561
Financing Receivable, Nonaccrual	74,812	74,812	14,329
Loans and Leases Receivable, Net of Deferred Income, Total	10,099,068	10,099,068	9,759,454
Commercial and Industrial Sector | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	671	671	716
Commercial and Industrial Sector | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	835	835	5,566
Commercial and Industrial Sector | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	441	441	282
Commercial real estate — owner occupied
Summarized details of Loans
Current	1,049,156	1,049,156	991,493
Financing Receivable, Nonaccrual	3,936	3,936	0
Loans and Leases Receivable, Net of Deferred Income, Total	1,054,969	1,054,969	991,722
Commercial real estate — owner occupied | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	1,877	1,877	218
Commercial real estate — owner occupied | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	0	0	12
Commercial real estate — owner occupied | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	0	0
Commercial and business lending
Summarized details of Loans
Current	11,071,464	11,071,464	10,730,053
Financing Receivable, Nonaccrual	78,748	78,748	14,329
Loans and Leases Receivable, Net of Deferred Income, Total	11,154,037	11,154,037	10,751,176
Commercial and business lending | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	2,548	2,548	934
Commercial and business lending | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	835	835	5,578
Commercial and business lending | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	441	441	282
Commercial real estate — investor
Summarized details of Loans
Current	5,197,977	5,197,977	5,049,897
Financing Receivable, Nonaccrual	10,882	10,882	29,380
Loans and Leases Receivable, Net of Deferred Income, Total	5,218,980	5,218,980	5,080,344
Commercial real estate — investor | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	10,120	10,120	1,067
Commercial real estate — investor | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	1	1	0
Commercial real estate — investor | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	0	0
Real estate construction
Summarized details of Loans
Current	2,130,606	2,130,606	2,155,077
Financing Receivable, Nonaccrual	103	103	105
Loans and Leases Receivable, Net of Deferred Income, Total	2,130,719	2,130,719	2,155,222
Real estate construction | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	10	10	39
Real estate construction | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	0	0	0
Real estate construction | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	0	0
Commercial real estate lending
Summarized details of Loans
Current	7,328,583	7,328,583	7,204,975
Financing Receivable, Nonaccrual	10,985	10,985	29,485
Loans and Leases Receivable, Net of Deferred Income, Total	7,349,699	7,349,699	7,235,565
Commercial real estate lending | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	10,130	10,130	1,105
Commercial real estate lending | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	1	1	0
Commercial real estate lending | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	0	0
Total commercial
Summarized details of Loans
Current	18,400,047	18,400,047	17,935,028
Financing Receivable, Nonaccrual	89,732	89,732	43,814
Loans and Leases Receivable, Net of Deferred Income, Total	18,503,736	18,503,736	17,986,742
Total commercial | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	12,678	12,678	2,040
Total commercial | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	836	836	5,578
Total commercial | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	441	441	282
Residential mortgage
Summarized details of Loans
Current	8,704,840	8,704,840	8,443,072
Financing Receivable, Nonaccrual	66,153	66,153	58,480
Loans and Leases Receivable, Net of Deferred Income, Total	8,782,645	8,782,645	8,511,550
Residential mortgage | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	11,652	11,652	9,811
Residential mortgage | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	0	0	63
Residential mortgage | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	0	124
Auto finance
Summarized details of Loans
Current	1,985,943	1,985,943	1,371,176
Financing Receivable, Nonaccrual	4,533	4,533	1,490
Loans and Leases Receivable, Net of Deferred Income, Total	2,007,164	2,007,164	1,382,073
Auto finance | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	14,335	14,335	8,238
Auto finance | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	2,353	2,353	1,170
Auto finance | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	0	0
Home equity
Summarized details of Loans
Current	612,045	612,045	611,259
Financing Receivable, Nonaccrual	7,917	7,917	7,487
Loans and Leases Receivable, Net of Deferred Income, Total	623,650	623,650	624,353
Home equity | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	2,876	2,876	5,149
Home equity | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	811	811	458
Home equity | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	0	0	0
Other consumer
Summarized details of Loans
Current	272,175	272,175	291,722
Financing Receivable, Nonaccrual	222	222	197
Loans and Leases Receivable, Net of Deferred Income, Total	275,993	275,993	294,851
Other consumer | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	1,255	1,255	1,018
Other consumer | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	625	625	592
Other consumer | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	1,715	1,715	1,322
Total consumer
Summarized details of Loans
Current	11,575,003	11,575,003	10,717,229
Financing Receivable, Nonaccrual	78,826	78,826	67,654
Loans and Leases Receivable, Net of Deferred Income, Total	11,689,451	11,689,451	10,812,828
Total consumer | 30-59 Days Past Due
Summarized details of Loans
Total Past Due	30,118	30,118	24,216
Total consumer | 60-89 Days Past Due
Summarized details of Loans
Total Past Due	3,789	3,789	2,283
Total consumer | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Summarized details of Loans
Total Past Due	$ 1,715	$ 1,715	$ 1,446