Loans and Leases Held for Investment at Amortized Cost, Net of Allowance For Loan and Lease Losses - Allowance For Credit Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan and lease losses, beginning of period	$ 327,852	$ 144,389	$ 0
Credit loss expense for loans and leases held for investment	243,570	266,679	140,951
Initial allowance for PCD loans acquired during the period	0	0	12,440
Charge-offs	(281,107)	(87,473)	(10,452)
Recoveries	20,072	4,257	1,450
Allowance for loan and lease losses, end of period	310,387	327,852	144,389
Radius Bancorp, Inc
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Credit loss expense for loans and leases held for investment			6,900
Unfunded Loan Commitment
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Reserve for unfunded lending commitments, beginning of period	1,878	1,231	0
Credit loss expense for unfunded lending commitments	(5)	647	1,231
Reserve for unfunded lending commitments, end of period	1,873	1,878	1,231
Unfunded Loan Commitment, Commitments To Extend Credit
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Reserve for unfunded lending commitments, beginning of period	138,000	110,800
Reserve for unfunded lending commitments, end of period	78,100	138,000	110,800
Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan and lease losses, beginning of period	312,489	128,812	0
Credit loss expense for loans and leases held for investment	244,518	265,359	136,789
Initial allowance for PCD loans acquired during the period	0	0	603
Charge-offs	(278,105)	(85,247)	(8,789)
Recoveries	19,159	3,565	209
Allowance for loan and lease losses, end of period	298,061	312,489	128,812
Consumer Portfolio Segment | Unfunded Loan Commitment
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Reserve for unfunded lending commitments, beginning of period	18	0	0
Credit loss expense for unfunded lending commitments	(18)	18	0
Reserve for unfunded lending commitments, end of period	0	18	0
Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan and lease losses, beginning of period	15,363	15,577	0
Credit loss expense for loans and leases held for investment	(948)	1,320	4,162
Initial allowance for PCD loans acquired during the period	0	0	11,837
Charge-offs	(3,002)	(2,226)	(1,663)
Recoveries	913	692	1,241
Allowance for loan and lease losses, end of period	12,326	15,363	15,577
Commercial Portfolio Segment | Unfunded Loan Commitment
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Reserve for unfunded lending commitments, beginning of period	1,860	1,231	0
Credit loss expense for unfunded lending commitments	13	629	1,231
Reserve for unfunded lending commitments, end of period	$ 1,873	$ 1,860	$ 1,231