Loans Receivable, Including Loans Held For Sale - Loans Receivable (Details) $ in Thousands	9 Months Ended
Sep. 30, 2020 USD ($) loan	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Receivable [Line Items]
Financing receivable, including loans held for sale, gross, total	$ 2,552,237		$ 554,722
Financing receivable, ratio to total, including loans held for sale (as a percent)	100.00%		100.00%
Financing receivable, gross, current	$ 262,402		$ 358,577
Financing receivable, gross, non-current	2,289,835		196,145
Allowance for loan losses, total	(42,628)		(36,682)
Allowance for loan losses, current	(42,628)		(36,682)
Allowance for loan losses, non-current	0		0
Total loans receivable, net	2,509,609		518,040
Loans receivable, net, current	219,774		321,895
Loans receivable, net, noncurrent	2,289,835		196,145
Loans receivable, including loans held for sale, current	299,943		546,908
Loans receivable, including loans held for sale, non-current	2,289,835		196,145
Pledged as collateral	6,320		15,737
Servicing asset	2,845		2,898
Increase in loans held for sale	7,773,535	$ 14,953,571
Financing Receivable, after Allowance for Credit Loss	2,552,237		554,722
Other borrowings	2,159,721		0
Loan Modifications, COVID-19
Receivable [Line Items]
Financing Receivable, after Allowance for Credit Loss	$ 23,532
Financing Receivable, Number Of Short-Term Deferments \| loan	10,213,000
Financing Receivable, after Allowance for Credit Loss, Percentage	0.94%
Small Business Administration (SBA), CARES Act, Paycheck Protection Program
Receivable [Line Items]
Financing Receivable, after Allowance for Credit Loss	$ 2,146,961
Other borrowings	2,159,721
Loans held for sale
Receivable [Line Items]
Financing receivable, including loans held for sale, gross, total	$ 80,169		$ 225,013
Financing receivable, ratio to total, including loans held for sale (as a percent)
Financing receivable, gross, current	$ 80,169		$ 225,013
Financing receivable, gross, non-current	0		0
Commercial real estate loans
Receivable [Line Items]
Financing receivable, including loans held for sale, gross, total	$ 644		$ 659
Financing receivable, ratio to total, including loans held for sale (as a percent)	0.00%		0.00%
Financing receivable, gross, current	$ 0		$ 0
Financing receivable, gross, non-current	644		659
Commercial and industrial
Receivable [Line Items]
Financing receivable, including loans held for sale, gross, total	$ 2,372,454		$ 251,349
Financing receivable, ratio to total, including loans held for sale (as a percent)	93.00%		45.00%
Financing receivable, gross, current	$ 213,334		$ 233,510
Financing receivable, gross, non-current	2,159,120		17,839
Consumer loans
Receivable [Line Items]
Financing receivable, including loans held for sale, gross, total	$ 179,139		$ 302,714
Financing receivable, ratio to total, including loans held for sale (as a percent)	7.00%		55.00%
Financing receivable, gross, current	$ 49,068		$ 125,067
Financing receivable, gross, non-current	130,071		177,647
Allowance for loan losses, total	(29,468)		(25,738)
Financing Receivable, after Allowance for Credit Loss	179,139		$ 302,714
WebBank
Receivable [Line Items]
Proceeds from loans held for sale	7,916,168	$ 14,929,832
Financing Receivable, Allowance for Credit Losses, Period Increase (Decrease)	$ 16,332
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease), Percentage	28.00%

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Carrying amount as of the balance sheet date of loans that have been pledged as collateral for borrowings. If the secured party has the right by contract or custom to sell or re-pledge the collateral, then the debtor reclassifies that asset and report that asset in its statement of financial position separately from other assets not so encumbered.

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