Loans and Allowance for Credit Losses for Loans - Summary of Activity in Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Jun. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2021
Allowance for loan losses:
Beginning balance	$ 436,432	$ 468,819		$ 458,655	$ 359,202
Allowance for PCD loans						$ 70,319
Loans charged-off	(8,918)	(9,995)		(52,818)	(17,857)
Charged-off loans recovered	3,440	15,605		8,347	21,197
Net (charge-offs) recoveries	5,478	(5,610)		44,471	(3,340)
Provision (credit) for loan losses	11,221	1,315		29,359	42,883
Ending balance	442,175	475,744	$ 468,819	442,175	475,744	359,202
Loans acquired with discounts related to credit quality
Allowance for loan losses:
Loans charged-off			(62,400)
Cumulative Effect, Period of Adoption, Adjustment
Allowance for loan losses:
Beginning balance				(1,368)
Cumulative Effect, Period of Adoption, Adjusted Balance
Allowance for loan losses:
Beginning balance				457,287
Commercial and industrial
Allowance for loan losses:
Beginning balance	128,245	144,539		139,941	103,090
Allowance for PCD loans						33,452
Loans charged-off	(7,487)	(5,033)		(37,399)	(11,144)
Charged-off loans recovered	3,043	13,236		6,615	16,012
Net (charge-offs) recoveries	4,444	(8,203)		30,784	(4,868)
Provision (credit) for loan losses	10,187	1,309		25,570	12,641
Ending balance	133,988	154,051	144,539	133,988	154,051	103,090
Commercial and industrial | Cumulative Effect, Period of Adoption, Adjustment
Allowance for loan losses:
Beginning balance				(739)
Commercial and industrial | Cumulative Effect, Period of Adoption, Adjusted Balance
Allowance for loan losses:
Beginning balance				139,202
Commercial Real Estate
Allowance for loan losses:
Beginning balance	239,695	277,227		259,408	217,490
Allowance for PCD loans						36,618
Loans charged-off	(255)	(4,000)		(12,226)	(4,173)
Charged-off loans recovered	5	1,729		33	2,060
Net (charge-offs) recoveries	250	2,271		12,193	2,113
Provision (credit) for loan losses	5,602	(7,176)		(1,579)	15,785
Ending balance	245,047	267,780	277,227	245,047	267,780	217,490
Commercial Real Estate | Cumulative Effect, Period of Adoption, Adjustment
Allowance for loan losses:
Beginning balance				(589)
Commercial Real Estate | Cumulative Effect, Period of Adoption, Adjusted Balance
Allowance for loan losses:
Beginning balance				258,819
Residential Mortgage
Allowance for loan losses:
Beginning balance	44,153	29,889		39,020	25,120
Allowance for PCD loans						206
Loans charged-off	(20)	0		(169)	(27)
Charged-off loans recovered	30	163		186	694
Net (charge-offs) recoveries	(10)	(163)		(17)	(667)
Provision (credit) for loan losses	458	6,105		5,596	10,164
Ending balance	44,621	36,157	29,889	44,621	36,157	25,120
Residential Mortgage | Cumulative Effect, Period of Adoption, Adjustment
Allowance for loan losses:
Beginning balance				(12)
Residential Mortgage | Cumulative Effect, Period of Adoption, Adjusted Balance
Allowance for loan losses:
Beginning balance				39,008
Consumer
Allowance for loan losses:
Beginning balance	24,339	17,164		20,286	13,502
Allowance for PCD loans						43
Loans charged-off	(1,156)	(962)		(3,024)	(2,513)
Charged-off loans recovered	362	477		1,513	2,431
Net (charge-offs) recoveries	794	485		1,511	82
Provision (credit) for loan losses	(5,026)	1,077		(228)	4,293
Ending balance	$ 18,519	$ 17,756	$ 17,164	18,519	$ 17,756	$ 13,502
Consumer | Cumulative Effect, Period of Adoption, Adjustment
Allowance for loan losses:
Beginning balance				(28)
Consumer | Cumulative Effect, Period of Adoption, Adjusted Balance
Allowance for loan losses:
Beginning balance				$ 20,258