Allowance for Credit Losses (Allowance for Credit Losses Methodology) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Feb. 28, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Allowance for credit losses on loans and leases
Balance, beginning of period		$ 404,603	$ 261,111	$ 301,135	$ 248,412
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date				26,492
(Recapture) provision for credit losses for loans and leases	$ 88,400	35,082	28,542	156,796	53,025
Charge-offs		(28,719)	(10,392)	(82,466)	(29,181)
Recoveries		5,594	3,804	14,603	10,809
Net recoveries (charge-offs)		(23,125)	(6,588)	(67,863)	(18,372)
Balance, end of period		416,560	283,065	416,560	283,065
Reserve for unfunded commitments
Balance, beginning of period		19,827	12,823	14,221	12,767
Off-Balance-Sheet, Credit Loss, Liability, acquired during the period				5,767
(Recapture) provision for credit losses on unfunded commitments		1,655	(970)	1,494	(914)
Balance, end of period		21,482	11,853	21,482	11,853
Total allowance for credit losses		438,042	294,918	438,042	294,918
Commercial real estate
Allowance for credit losses on loans and leases
Balance, beginning of period		118,954	88,983	77,813	99,075
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date				8,736
(Recapture) provision for credit losses for loans and leases		2,734	(3,563)	35,046	(13,745)
Charge-offs		0	0	(174)	(8)
Recoveries		31	123	298	221
Net recoveries (charge-offs)		31	123	124	213
Balance, end of period		121,719	85,543	121,719	85,543
Reserve for unfunded commitments
Balance, beginning of period		10,000	7,351	7,207	8,461
Off-Balance-Sheet, Credit Loss, Liability, acquired during the period				2,257
(Recapture) provision for credit losses on unfunded commitments		(11)	(1,994)	525	(3,104)
Balance, end of period		9,989	5,357	9,989	5,357
Total allowance for credit losses		131,708	90,900	131,708	90,900
Commercial
Allowance for credit losses on loans and leases
Balance, beginning of period		211,651	131,455	167,135	117,573
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date				17,204
(Recapture) provision for credit losses for loans and leases		35,952	26,762	106,979	52,058
Charge-offs		(26,629)	(9,459)	(77,913)	(26,352)
Recoveries		4,901	2,842	12,470	8,321
Net recoveries (charge-offs)		(21,728)	(6,617)	(65,443)	(18,031)
Balance, end of period		225,875	151,600	225,875	151,600
Reserve for unfunded commitments
Balance, beginning of period		5,821	2,232	3,049	2,028
Off-Balance-Sheet, Credit Loss, Liability, acquired during the period				3,066
(Recapture) provision for credit losses on unfunded commitments		1,579	579	1,285	783
Balance, end of period		7,400	2,811	7,400	2,811
Total allowance for credit losses		233,275	154,411	233,275	154,411
Residential
Allowance for credit losses on loans and leases
Balance, beginning of period		65,941	36,586	50,329	29,068
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date				454
(Recapture) provision for credit losses for loans and leases		(4,619)	4,307	10,605	11,603
Charge-offs		(206)	(4)	(458)	(171)
Recoveries		156	249	342	638
Net recoveries (charge-offs)		(50)	245	(116)	467
Balance, end of period		61,272	41,138	61,272	41,138
Reserve for unfunded commitments
Balance, beginning of period		3,018	2,735	3,196	1,957
Off-Balance-Sheet, Credit Loss, Liability, acquired during the period				268
(Recapture) provision for credit losses on unfunded commitments		67	304	(379)	1,082
Balance, end of period		3,085	3,039	3,085	3,039
Total allowance for credit losses		64,357	44,177	64,357	44,177
Consumer Portfolio Segment [Member]
Allowance for credit losses on loans and leases
Balance, beginning of period		8,057	4,087	5,858	2,696
Financing Receivable, Purchased with Credit Deterioration, Allowance for Credit Loss at Acquisition Date				98
(Recapture) provision for credit losses for loans and leases		1,015	1,036	4,166	3,109
Charge-offs		(1,884)	(929)	(3,921)	(2,650)
Recoveries		506	590	1,493	1,629
Net recoveries (charge-offs)		(1,378)	(339)	(2,428)	(1,021)
Balance, end of period		7,694	4,784	7,694	4,784
Reserve for unfunded commitments
Balance, beginning of period		988	505	769	321
Off-Balance-Sheet, Credit Loss, Liability, acquired during the period				176
(Recapture) provision for credit losses on unfunded commitments		20	141	63	325
Balance, end of period		1,008	646	1,008	646
Total allowance for credit losses		$ 8,702	$ 5,430	$ 8,702	$ 5,430