Allowance for Credit Losses (Allowance for Credit Losses Methodology) (Details) - USD ($) $ in Thousands		12 Months Ended
	Feb. 28, 2023	Dec. 31, 2023	Dec. 31, 2022
Allowance for credit losses on loans and leases
Balance, beginning of period		$ 301,135	$ 248,412
Initial ACL on PCD loans acquired during the period		26,492
Provision for credit losses for loans and leases (1)	$ 88,400	209,979	83,605
Charge-offs		(116,974)	(44,989)
Recoveries		20,239	14,107
Net (charge-offs) recoveries		(96,735)	(30,882)
Balance, end of period		440,871	301,135
Reserve for unfunded commitments
Balance, beginning of period		14,221	12,767
Initial ACL recorded for unfunded commitments acquired during the period		5,767
Provision (recapture) for credit losses on unfunded commitments		3,220	1,454
Balance, end of period		23,208	14,221
Total allowance for credit losses		464,079	315,356
Commercial Real Estate Portfolio Segment
Allowance for credit losses on loans and leases
Balance, beginning of period		77,813	99,075
Initial ACL on PCD loans acquired during the period		8,736
Provision for credit losses for loans and leases (1)		39,809	(21,510)
Charge-offs		(803)	(136)
Recoveries		333	384
Net (charge-offs) recoveries		(470)	248
Balance, end of period		125,888	77,813
Reserve for unfunded commitments
Balance, beginning of period		7,207	8,461
Initial ACL recorded for unfunded commitments acquired during the period		2,257
Provision (recapture) for credit losses on unfunded commitments		1,706	(1,254)
Balance, end of period		11,170	7,207
Total allowance for credit losses		137,058	85,020
Commercial Portfolio Segment
Allowance for credit losses on loans and leases
Balance, beginning of period		167,135	117,573
Initial ACL on PCD loans acquired during the period		17,204
Provision for credit losses for loans and leases (1)		153,460	79,606
Charge-offs		(109,862)	(41,073)
Recoveries		16,884	11,029
Net (charge-offs) recoveries		(92,978)	(30,044)
Balance, end of period		244,821	167,135
Reserve for unfunded commitments
Balance, beginning of period		3,049	2,028
Initial ACL recorded for unfunded commitments acquired during the period		3,066
Provision (recapture) for credit losses on unfunded commitments		1,726	1,021
Balance, end of period		7,841	3,049
Total allowance for credit losses		252,662	170,184
Residential Portfolio Segment
Allowance for credit losses on loans and leases
Balance, beginning of period		50,329	29,068
Initial ACL on PCD loans acquired during the period		454
Provision for credit losses for loans and leases (1)		10,645	20,823
Charge-offs		(547)	(224)
Recoveries		1,123	662
Net (charge-offs) recoveries		576	438
Balance, end of period		62,004	50,329
Reserve for unfunded commitments
Balance, beginning of period		3,196	1,957
Initial ACL recorded for unfunded commitments acquired during the period		268
Provision (recapture) for credit losses on unfunded commitments		(524)	1,239
Balance, end of period		2,940	3,196
Total allowance for credit losses		64,944	53,525
Consumer Portfolio Segment
Allowance for credit losses on loans and leases
Balance, beginning of period		5,858	2,696
Initial ACL on PCD loans acquired during the period		98
Provision for credit losses for loans and leases (1)		6,065	4,686
Charge-offs		(5,762)	(3,556)
Recoveries		1,899	2,032
Net (charge-offs) recoveries		(3,863)	(1,524)
Balance, end of period		8,158	5,858
Reserve for unfunded commitments
Balance, beginning of period		769	321
Initial ACL recorded for unfunded commitments acquired during the period		176
Provision (recapture) for credit losses on unfunded commitments		312	448
Balance, end of period		1,257	769
Total allowance for credit losses		$ 9,415	$ 6,627