Allowance for Credit Losses - Allowance for Credit Loss Activity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 99,915	$ 115,101	$ 98,576	$ 117,612
Provision for credit losses on loans	1,192	2,008	495	5,308
Charge-offs	(7,678)	(8,737)	(8,661)	(15,270)
Recoveries	4,666	1,264	7,685	1,985
Net Recoveries/(Charge-offs)	(3,012)	(7,473)	(976)	(13,285)
Balance at End of Period	98,095	109,636	98,095	109,636
Commercial Loans | Commercial real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	48,903	66,842	50,700	65,656
Provision for credit losses on loans	(3,678)	2,937	(5,475)	4,933
Charge-offs	(199)	(7,558)	(199)	(8,369)
Recoveries	288	965	288	965
Net Recoveries/(Charge-offs)	89	(6,594)	89	(7,403)
Balance at End of Period	45,314	63,186	45,314	63,186
Commercial Loans | Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	22,237	14,663	19,727	16,100
Provision for credit losses on loans	948	225	768	2,953
Charge-offs	(5,797)	(473)	(5,798)	(4,774)
Recoveries	4,138	11	6,829	148
Net Recoveries/(Charge-offs)	(1,659)	(462)	1,031	(4,627)
Balance at End of Period	21,526	14,426	21,526	14,426
Commercial Loans | Commercial construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	5,329	6,329	5,355	7,239
Provision for credit losses on loans	1,254	(426)	1,227	(1,337)
Charge-offs	0	0	0	0
Recoveries	0	2	1	3
Net Recoveries/(Charge-offs)	0	2	1	3
Balance at End of Period	6,583	5,905	6,583	5,905
Commercial Loans | Business banking
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	11,497	15,680	11,338	15,917
Provision for credit losses on loans	1,668	(560)	2,207	(46)
Charge-offs	(1,141)	(410)	(1,746)	(1,327)
Recoveries	133	47	358	213
Net Recoveries/(Charge-offs)	(1,008)	(363)	(1,388)	(1,115)
Balance at End of Period	12,157	14,756	12,157	14,756
Consumer Loans | Consumer real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	9,118	8,981	8,733	10,014
Provision for credit losses on loans	582	(410)	1,010	(1,254)
Charge-offs	(60)	(76)	(138)	(347)
Recoveries	33	152	68	234
Net Recoveries/(Charge-offs)	(27)	76	(70)	(113)
Balance at End of Period	9,673	8,647	9,673	8,647
Consumer Loans | Other Consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	2,831	2,606	2,723	2,686
Provision for credit losses on loans	418	243	758	61
Charge-offs	(481)	(221)	(780)	(453)
Recoveries	74	88	141	423
Net Recoveries/(Charge-offs)	(407)	(132)	(639)	(30)
Balance at End of Period	$ 2,842	$ 2,717	$ 2,842	$ 2,717