Loans and Allowance for Credit Losses for Loans - Summary of Allocation of Allowance for Loan Losses and Related Loans by Loan Portfolio Segment Disaggregated Based on Allowance Measurement Methodology (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Mar. 31, 2026	Dec. 31, 2025	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for credit losses	$ 90,541		$ 81,987
Collectively evaluated for credit losses	500,059		501,413
Total	590,600	$ 584,500	583,400	$ 579,500	$ 578,200	$ 558,850
Individually evaluated for credit losses	447,583		416,153
Collectively evaluated for credit losses	52,019,668		49,720,575
Total	52,467,251		50,136,728
Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for credit losses	79,405		71,188
Collectively evaluated for credit losses	119,505		109,677
Total	198,910	186,143	180,865	173,415	184,700	173,002
Individually evaluated for credit losses	164,930		159,594
Collectively evaluated for credit losses	11,796,312		10,801,925
Total	11,961,242		10,961,519
Commercial Real Estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for credit losses	11,116		10,777
Collectively evaluated for credit losses	307,952		316,649
Total	319,068	324,793	327,426	334,979	321,662	304,148
Individually evaluated for credit losses	250,548		225,982
Collectively evaluated for credit losses	30,098,287		29,018,000
Total	30,348,835		29,243,982
Residential Mortgage
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for credit losses	20		22
Collectively evaluated for credit losses	48,885		53,507
Total	48,905	51,700	53,529	48,830	48,906	58,895
Individually evaluated for credit losses	29,483		28,569
Collectively evaluated for credit losses	5,953,458		5,797,623
Total	5,982,941		5,826,192
Consumer loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for credit losses	0		0
Collectively evaluated for credit losses	23,717		21,580
Total	23,717	$ 21,864	21,580	$ 22,276	$ 22,932	$ 22,805
Individually evaluated for credit losses	2,622		2,008
Collectively evaluated for credit losses	4,171,611		4,103,027
Total	$ 4,174,233		$ 4,105,035