Allowance for Credit Losses - Allowance for Credit Loss Activity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 98,576	$ 117,612
Provision for credit losses on loans	(698)	3,301
Charge-offs	(982)	(6,532)
Recoveries	3,019	720
Net Recoveries/(Charge-offs)	2,037	(5,812)
Balance at End of Period	99,915	115,101
Commercial | Commercial real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	50,700	65,656
Provision for credit losses on loans	(1,996)	1,996
Charge-offs	0	(810)
Recoveries	199	0
Net Recoveries/(Charge-offs)	199	(810)
Balance at End of Period	48,903	66,842
Commercial | Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	19,727	16,100
Provision for credit losses on loans	(206)	2,728
Charge-offs	0	(4,302)
Recoveries	2,716	137
Net Recoveries/(Charge-offs)	2,716	(4,165)
Balance at End of Period	22,237	14,663
Commercial | Commercial construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	5,355	7,239
Provision for credit losses on loans	(27)	(911)
Charge-offs	0	0
Recoveries	1	1
Net Recoveries/(Charge-offs)	1	1
Balance at End of Period	5,329	6,329
Commercial | Business banking
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	11,338	15,917
Provision for credit losses on loans	765	514
Charge-offs	(606)	(917)
Recoveries	0	166
Net Recoveries/(Charge-offs)	(606)	(751)
Balance at End of Period	11,497	15,680
Consumer | Consumer real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	8,733	10,014
Provision for credit losses on loans	426	(844)
Charge-offs	(78)	(271)
Recoveries	37	82
Net Recoveries/(Charge-offs)	(41)	(189)
Balance at End of Period	9,118	8,981
Consumer | Other consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	2,723	2,686
Provision for credit losses on loans	340	(182)
Charge-offs	(298)	(232)
Recoveries	66	334
Net Recoveries/(Charge-offs)	(232)	102
Balance at End of Period	$ 2,831	$ 2,606