Allowance for Credit Losses - Allowance for Credit Loss Activity (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period		$ 117,612	$ 62,224
Provision for credit losses on loans		15,494	131,421
Charge-offs		(37,524)	(106,365)
Recoveries		2,994	2,986
Net (Charge-offs)/Recoveries		(34,530)	(103,379)
Balance at End of Period		98,576	117,612
Customer fraud, check kiting
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Charge-offs	$ (58,700)
Commercial | Commercial real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period		65,656	30,577
Provision for credit losses on loans		(2,569)	56,489
Charge-offs		(13,444)	(26,460)
Recoveries		1,057	240
Net (Charge-offs)/Recoveries		(12,387)	(26,220)
Balance at End of Period		50,700	65,656
Commercial | Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period		16,100	15,681
Provision for credit losses on loans		23,746	65,288
Charge-offs		(20,923)	(74,282)
Recoveries		804	1,560
Net (Charge-offs)/Recoveries		(20,119)	(72,722)
Balance at End of Period		19,727	16,100
Commercial | Commercial construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period		7,239	7,900
Provision for credit losses on loans		(1,842)	2,986
Charge-offs		(56)	(454)
Recoveries		14	183
Net (Charge-offs)/Recoveries		(42)	(271)
Balance at End of Period		5,355	7,239
Commercial | Business banking
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period		15,917	0
Provision for credit losses on loans		(3,159)	5,303
Charge-offs		(1,580)	(2,612)
Recoveries		160	328
Net (Charge-offs)/Recoveries		(1,420)	(2,284)
Balance at End of Period		11,338	15,917
Consumer | Consumer real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period		10,014	6,337
Provision for credit losses on loans		(1,020)	(368)
Charge-offs		(569)	(667)
Recoveries		308	187
Net (Charge-offs)/Recoveries		(261)	(480)
Balance at End of Period		8,733	10,014
Consumer | Other consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period		2,686	1,729
Provision for credit losses on loans		338	1,723
Charge-offs		(952)	(1,890)
Recoveries		651	488
Net (Charge-offs)/Recoveries		(301)	(1,402)
Balance at End of Period		$ 2,723	2,686
Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			27,346
Cumulative Effect, Period of Adoption, Adjustment | Commercial | Commercial real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			4,810
Cumulative Effect, Period of Adoption, Adjustment | Commercial | Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			7,853
Cumulative Effect, Period of Adoption, Adjustment | Commercial | Commercial construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			(3,376)
Cumulative Effect, Period of Adoption, Adjustment | Commercial | Business banking
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			12,898
Cumulative Effect, Period of Adoption, Adjustment | Consumer | Consumer real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			4,525
Cumulative Effect, Period of Adoption, Adjustment | Consumer | Other consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			$ 636