Allowance for Credit Losses (Allowance for Credit Losses Methodology) (Details) - USD ($) $ in Thousands		3 Months Ended
	Feb. 28, 2023	Mar. 31, 2023	Mar. 31, 2022
Allowance for credit losses on loans and leases
Balance, beginning of period		$ 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	106,498	5,696
Charge-offs		(20,269)	(8,910)
Recoveries		3,608	3,366
Net recoveries (charge-offs)		(16,661)	(5,544)
Balance, end of period		417,464	248,564
Reserve for unfunded commitments
Balance, beginning of period		14,221	12,767
Off-Balance-Sheet, Credit Loss, Liability, acquired during the period		5,767
Provision (recapture) for credit losses on unfunded commitments		(959)	151
Balance, end of period		19,029	12,918
Total allowance for credit losses		436,493	261,482
Commercial Real Estate Portfolio Segment [Member]
Allowance for credit losses on loans and leases
Balance, beginning of period		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		24,483	(7,462)
Charge-offs		0	0
Recoveries		58	25
Net recoveries (charge-offs)		58	25
Balance, end of period		111,090	91,638
Reserve for unfunded commitments
Balance, beginning of period		7,207	8,461
Off-Balance-Sheet, Credit Loss, Liability, acquired during the period		2,257
Provision (recapture) for credit losses on unfunded commitments		(1,059)	277
Balance, end of period		8,405	8,738
Total allowance for credit losses		119,495	100,376
Commercial
Allowance for credit losses on loans and leases
Balance, beginning of period		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		70,997	8,812
Charge-offs		(19,248)	(7,858)
Recoveries		3,058	2,545
Net recoveries (charge-offs)		(16,190)	(5,313)
Balance, end of period		239,146	121,072
Reserve for unfunded commitments
Balance, beginning of period		3,049	2,028
Off-Balance-Sheet, Credit Loss, Liability, acquired during the period		3,066
Provision (recapture) for credit losses on unfunded commitments		266	(408)
Balance, end of period		6,381	1,620
Total allowance for credit losses		245,527	122,692
Residential
Allowance for credit losses on loans and leases
Balance, beginning of period		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		9,955	2,872
Charge-offs		(248)	(167)
Recoveries		123	173
Net recoveries (charge-offs)		(125)	6
Balance, end of period		60,613	31,946
Reserve for unfunded commitments
Balance, beginning of period		3,196	1,957
Off-Balance-Sheet, Credit Loss, Liability, acquired during the period		268
Provision (recapture) for credit losses on unfunded commitments		(144)	236
Balance, end of period		3,320	2,193
Total allowance for credit losses		63,933	34,139
Consumer Portfolio Segment [Member]
Allowance for credit losses on loans and leases
Balance, beginning of period		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		1,063	1,474
Charge-offs		(773)	(885)
Recoveries		369	623
Net recoveries (charge-offs)		(404)	(262)
Balance, end of period		6,615	3,908
Reserve for unfunded commitments
Balance, beginning of period		769	321
Off-Balance-Sheet, Credit Loss, Liability, acquired during the period		176
Provision (recapture) for credit losses on unfunded commitments		(22)	46
Balance, end of period		923	367
Total allowance for credit losses		$ 7,538	$ 4,275