Federal and State Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets [Abstract]
Available for sale securities mark to market	$ 183,724	$ 255,244
Credit loss reserves	76,361	69,385
Lease liability	61,204	49,839
Deferred compensation	41,350	34,645
Unearned fees	12,682	12,915
Purchased loan discount	3,546	4,955
Share-based compensation	6,068	4,625
Valuation adjustments	4,860	5,792
Other	47,169	42,808
Total deferred tax assets	436,964	480,208
Valuation Allowance [Abstract]
Valuation allowance	0	0
Deferred tax liabilities [Abstract]
Right-of-use asset	51,943	40,741
Mortgage servicing rights	47,646	49,001
Acquired identifiable intangible	8,166	11,280
Depreciation	4,578	7,163
Lease financing	12,148	12,333
Other	42,887	38,357
Total deferred tax liabilities	167,368	158,875
Net deferred tax assets, net	269,596	321,333
Current income tax expense [Abstract]
Federal	152,600	127,144	$ 121,196
State	19,298	18,185	21,065
Total current income tax expense	171,898	145,329	142,261
Deferred income tax expense [Abstract]
Federal	(17,973)	(4,700)	29,777
State	(1,810)	(765)	7,737
Total deferred income tax expense (benefit)	(19,783)	(5,465)	37,514
Total income tax expense	152,115	139,864	179,775
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Federal statutory tax	143,482	138,633	167,181
Tax exempt revenue	(5,786)	(5,714)	(6,084)
Effect of state income taxes, net of federal benefit	13,330	13,490	22,489
Utilization of tax credits, net of proportional amortization of low-income housing, new market, and historical tax credits	(2,673)	(8,883)	(8,801)
Other, net	3,762	2,338	4,990
Total income tax expense	$ 152,115	$ 139,864	$ 179,775
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal statutory tax (in thousandths)	21.00%	21.00%	21.00%
Tax exempt revenue (in thousandths)	(0.80%)	(0.80%)	(0.70%)
Effect of state income taxes, net of federal benefit (in thousandths)	2.00%	2.00%	2.80%
Utilization of tax credits, net of proportional amortization of low-income housing limited partnership investments (in thousandths)	(0.40%)	(1.40%)	(1.10%)
Other, net (in thousandths)	0.50%	0.40%	0.60%
Total (in thousandths)	22.30%	21.20%	22.60%
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance as of January 1	$ 19,583	$ 21,092	$ 22,902
Additions for tax for current year positions	3,239	3,465	3,961
Settlements during the period	0	0	(1,754)
Lapses of applicable statute of limitations	(4,865)	(4,974)	(4,017)
Balance as of December 31	17,957	19,583	21,092
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	14,100
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	1,600	1,800	$ 2,300
Unrecognized Tax Benefits, Penalties and Interest Accrued	$ 5,700	$ 6,000
Unrecognized Tax Benefits, Number of Reporting Periods Open for Examination, Federal	3
Unrecognized Tax Benefits, Number of Reporting Periods Open for Examination, State, Minimum	3
Unrecognized Tax Benefits, Number of Reporting Periods Open for Examination, State, Maximum	6