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Loans and Leases Held for Investment, Net of Allowance For Loan and Lease Losses - Allowance For Credit Losses (Details) - USD ($) $ in Thousands			3 Months Ended	9 Months Ended
	Feb. 01, 2021	Jan. 31, 2021	Sep. 30, 2021	Sep. 30, 2021
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan and lease losses, beginning of period			$ 71,081	$ 0
Credit loss expense for loans and leases held for investment			37,133	95,662
Initial allowance for PCD loans acquired during the period			0	12,440
Charge-offs			(4,336)	(4,582)
Recoveries	$ 12,400		858	1,216
Allowance for loan and lease losses, end of period			104,736	104,736
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Initial allowance for PCD assets acquired during the period at acquisition date				30,378
Unfunded Loan Commitment
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Reserve for unfunded lending commitments, beginning of period			390	0
Credit loss expense for unfunded lending commitments			887	1,277
Reserve for unfunded lending commitments, end of period			1,277	1,277
Unfunded Loan Commitment, Commitments To Extend Credit
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Reserve for unfunded lending commitments, end of period			115,500	115,500
PCD Loans Acquired
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Charge-offs		$ (18,000)
Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan and lease losses, beginning of period			54,058	0
Credit loss expense for loans and leases held for investment			37,695	91,194
Initial allowance for PCD loans acquired during the period			0	603
Charge-offs			(3,142)	(3,232)
Recoveries			20	66
Allowance for loan and lease losses, end of period			88,631	88,631
Consumer Portfolio Segment \| Unfunded Loan Commitment
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Reserve for unfunded lending commitments, beginning of period			0	0
Credit loss expense for unfunded lending commitments			50	50
Reserve for unfunded lending commitments, end of period			50	50
Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan and lease losses, beginning of period			17,023	0
Credit loss expense for loans and leases held for investment			(562)	4,468
Initial allowance for PCD loans acquired during the period			0	11,837
Charge-offs			(1,194)	(1,350)
Recoveries			838	1,150
Allowance for loan and lease losses, end of period			16,105	16,105
Commercial Portfolio Segment \| Unfunded Loan Commitment
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Reserve for unfunded lending commitments, beginning of period			390	0
Credit loss expense for unfunded lending commitments			837	1,227
Reserve for unfunded lending commitments, end of period			$ 1,227	$ 1,227