Allowance for Credit Losses - Allowance for Credit Loss Activity (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($)
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 62,224
Provision for credit losses on loans	18,430
Charge-offs	(11,430)
Recoveries	274
Net (Charge-offs)/Recoveries	(11,156)
Balance at End of Period	96,850
Commercial | Commercial real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	30,577
Provision for credit losses on loans	7,639
Charge-offs	(442)
Recoveries	27
Net (Charge-offs)/Recoveries	(415)
Balance at End of Period	42,611
Commercial | Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	15,681
Provision for credit losses on loans	6,196
Charge-offs	(9,879)
Recoveries	19
Net (Charge-offs)/Recoveries	(9,860)
Balance at End of Period	19,870
Commercial | Commercial construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	7,900
Provision for credit losses on loans	2,309
Charge-offs	(229)
Recoveries	2
Net (Charge-offs)/Recoveries	(227)
Balance at End of Period	6,606
Commercial | Business banking
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	0	[1]
Provision for credit losses on loans	1,194	[1]
Charge-offs	(460)	[1]
Recoveries	74	[1]
Net (Charge-offs)/Recoveries	(386)	[1]
Balance at End of Period	13,706	[1]
Consumer | Consumer real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	6,337
Provision for credit losses on loans	472
Charge-offs	(172)
Recoveries	38
Net (Charge-offs)/Recoveries	(134)
Balance at End of Period	11,200
Consumer | Other consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	1,729
Provision for credit losses on loans	620
Charge-offs	(248)
Recoveries	114
Net (Charge-offs)/Recoveries	(134)
Balance at End of Period	2,857
Impact of CECL adoption
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	27,352
Impact of CECL adoption | Commercial | Commercial real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	4,810
Impact of CECL adoption | Commercial | Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	7,853
Impact of CECL adoption | Commercial | Commercial construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	(3,376)
Impact of CECL adoption | Commercial | Business banking
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	12,898	[1]
Impact of CECL adoption | Consumer | Consumer real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	4,525
Impact of CECL adoption | Consumer | Other consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 642

[1] In connection with our adoption of ASU 2016-13, we made changes to our loan portfolio segments to align with the methodology applied in determining the allowance under CECL. Our new segmentation breaks out business banking loans from our other loan segments: CRE, C&I , commercial construction, consumer real estate and other consumer. The business banking allowance balance at the beginning of period is included in the other segments and reclassified to business banking through the impact of CECL adoption line.