Allowance for Credit Losses - Allowance for Credit Loss Activity (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 98,095	$ 109,637	$ 98,576	$ 117,612
Provision for credit losses on loans	2,309	2,302	2,804	7,612
Charge-offs	(1,239)	(4,207)	(9,899)	(19,477)
Recoveries	529	616	8,213	2,601
Net (Charge-offs)/ Recoveries	(710)	(3,591)	(1,686)	(16,876)
Balance at End of Period	99,694	108,348	99,694	108,348
Commercial Loans | Commercial real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	45,314	63,186	50,700	65,656
Provision for credit losses on loans	(2,997)	(7,856)	(8,471)	(2,922)
Charge-offs	(628)	(3,661)	(827)	(12,030)
Recoveries	145	1	432	966
Net (Charge-offs)/ Recoveries	(483)	(3,660)	(395)	(11,064)
Balance at End of Period	41,834	51,670	41,834	51,670
Commercial Loans | Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	21,526	14,426	19,727	16,100
Provision for credit losses on loans	3,806	11,599	4,573	14,552
Charge-offs	0	(2)	(5,797)	(4,777)
Recoveries	6	216	6,835	364
Net (Charge-offs)/ Recoveries	6	214	1,038	(4,413)
Balance at End of Period	25,338	26,239	25,338	26,239
Commercial Loans | Commercial construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	6,583	5,905	5,355	7,239
Provision for credit losses on loans	(1,159)	1,391	68	54
Charge-offs	0	(56)	0	(56)
Recoveries	0	2	1	5
Net (Charge-offs)/ Recoveries	0	(54)	1	(51)
Balance at End of Period	5,424	7,242	5,424	7,242
Commercial Loans | Business banking
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	12,157	14,756	11,338	15,917
Provision for credit losses on loans	950	(2,689)	3,158	(2,736)
Charge-offs	(178)	(167)	(1,924)	(1,494)
Recoveries	242	241	599	454
Net (Charge-offs)/ Recoveries	64	74	(1,325)	(1,040)
Balance at End of Period	13,171	12,141	13,171	12,141
Consumer Loans | Consumer real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	9,673	8,647	8,733	10,014
Provision for credit losses on loans	1,075	(80)	2,083	(1,335)
Charge-offs	(161)	(76)	(299)	(422)
Recoveries	39	33	109	267
Net (Charge-offs)/ Recoveries	(122)	(43)	(190)	(155)
Balance at End of Period	10,626	8,524	10,626	8,524
Consumer Loans | Other Consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	2,842	2,717	2,723	2,686
Provision for credit losses on loans	634	(63)	1,393	(1)
Charge-offs	(272)	(245)	(1,052)	(698)
Recoveries	97	123	237	545
Net (Charge-offs)/ Recoveries	(175)	(122)	(815)	(153)
Balance at End of Period	$ 3,301	$ 2,532	$ 3,301	$ 2,532