Business Acquisition - Summary of Income Statement Reclassification Adjustments (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021		Sep. 30, 2020
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Net fair value adjustments		$ 2,705	$ (3,326)	$ (6,714)	[1]	$ (99,144)	[1]
Net interest income	[2]	65,288	13,294	129,699		56,429
Gain on sales of loans		21,907	7,739	49,547		23,724
Non-interest income
Marketplace revenue	[2]	174,556	54,635	408,018		175,993
Other non-interest income	[2]	6,322	3,115	18,670		10,166
Total non-interest income	[2]	180,878	57,750	426,688		186,159
Interest income
Interest on loans held for sale	[2]	8,536	14,916	22,387		67,579
Interest on retail and certificate loans held for investment at fair value	[2]	12,172	27,117	48,448		92,193
Interest on other loans held for investment at fair value	[2]	973	1,948	3,674		6,021
Interest on securities available for sale	[2]	3,180	2,754	7,954		9,930
Other interest income	[2]	355	38	701		1,021
Total interest income	[2]	82,860	46,773	195,177		176,744
Interest expense
Interest on short-term borrowings	[2]	849	3,179	3,116		16,332
Interest on retail notes, certificates and secured borrowings	[2]	12,172	27,117	48,448		92,193
Interest on Structured Program borrowings	[2]	2,120	3,046	7,996		11,418
Interest on other long-term debt	[2]	532	137	1,306		372
Total interest expense	[2]	17,572	33,479	65,478		120,315
Total net revenue	[2]	246,166	71,044	556,387		242,588
Provision for credit losses	[2]	37,524	(3,669)	93,651	[1]	3,800	[1]
Non-interest expense
Compensation and benefits	[2]	73,304	58,649	209,649		199,991
Marketing	[2]	50,782	2,135	105,434		43,030
Equipment and software	[2]	10,297	6,430	27,471		20,931
Occupancy	[2]	6,486	6,466	19,543		22,241
Depreciation and amortization	[2]	10,549	12,348	33,823		41,832
Professional services	[2]	11,750	8,817	34,873		32,723
Other non-interest expense	[2]	15,607	14,267	42,373		38,678
Total non-interest expense	[2]	178,775	109,112	473,166		399,426
Income tax benefit		2,682	(74)	98		245
Consolidated net income (loss)		27,185	(34,325)	(10,528)	[1]	(160,883)	[1]
LendingClub
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Interest income			0			0
Net fair value adjustments			0			0
Gain on sales of loans			0			0
Net investor revenue			0			0
Other revenue			0			0
Total net revenue			0			0
Non-interest income
Marketplace revenue			54,635			175,993
Other non-interest income			3,115			10,166
Total non-interest income			57,750			186,159
Interest income
Interest on loans held for sale			14,916			67,579
Interest on retail and certificate loans held for investment at fair value			27,117			92,193
Interest on other loans held for investment at fair value			1,948			6,021
Interest on securities available for sale			2,754			9,930
Other interest income			38			1,021
Total interest income			46,773			176,744
Interest expense
Interest on short-term borrowings			3,179			16,332
Interest on retail notes, certificates and secured borrowings			27,117			92,193
Interest on Structured Program borrowings			3,046			11,418
Interest on other long-term debt			137			372
Total interest expense			33,479			120,315
Net interest income			13,294			56,429
Total net revenue			71,044			242,588
Provision for credit losses			(3,669)			3,800
Operating expenses
Sales and marketing			0			0
Origination and servicing			0			0
Engineering and product development			0			0
Other general and administrative			0			0
Total operating expenses			0			0
Non-interest expense
Compensation and benefits			58,649			199,991
Marketing			2,135			43,030
Equipment and software			6,430			20,931
Occupancy			6,466			22,241
Depreciation and amortization			12,348			41,832
Professional services			8,817			32,723
Other non-interest expense			14,267			38,678
Total non-interest expense			109,112			399,426
Income (Loss) before income tax expense			(34,399)			(160,638)
Income tax benefit			(74)			245
Consolidated net income (loss)			(34,325)			(160,883)
Transaction fees
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Net Revenue		$ 129,125	24,372	$ 298,486		164,489
Transaction fees | LendingClub
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Net Revenue			0			0
Investor fees | LendingClub
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Net Revenue			0			0
LendingClub Historical Presentation | LendingClub
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Interest income			46,773			176,744
Interest expense			(32,440)			(114,447)
Net fair value adjustments			(696)			(108,812)
Net interest income			13,637			(46,515)
Gain on sales of loans			7,739			23,724
Net investor revenue			47,226			64,133
Other revenue			3,115			10,166
Total net revenue			74,713			238,788
Non-interest income
Marketplace revenue			0			0
Other non-interest income			0			0
Total non-interest income			0			0
Interest income
Interest on loans held for sale			0			0
Interest on retail and certificate loans held for investment at fair value			0			0
Interest on other loans held for investment at fair value			0			0
Interest on securities available for sale			0			0
Other interest income			0			0
Total interest income			0			0
Interest expense
Interest on short-term borrowings			0			0
Interest on retail notes, certificates and secured borrowings			0			0
Interest on Structured Program borrowings			0			0
Interest on other long-term debt			0			0
Total net revenue			0			0
Provision for credit losses			0			0
Operating expenses
Sales and marketing			7,201			65,708
Origination and servicing			15,595			54,419
Engineering and product development			31,984			109,861
Other general and administrative			54,332			169,438
Total operating expenses			109,112			399,426
Non-interest expense
Compensation and benefits			0			0
Marketing			0			0
Equipment and software			0			0
Occupancy			0			0
Depreciation and amortization			0			0
Professional services			0			0
Other non-interest expense			0			0
Total non-interest expense			0			0
Income (Loss) before income tax expense			(34,399)			(160,638)
Income tax benefit			(74)			245
Consolidated net income (loss)			(34,325)			(160,883)
LendingClub Historical Presentation | Transaction fees | LendingClub
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Net Revenue			24,372			164,489
LendingClub Historical Presentation | Investor fees | LendingClub
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Net Revenue			25,850			86,924
Reclassification Adjustments | LendingClub
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Interest income			(46,773)			(176,744)
Interest expense			32,440			114,447
Net fair value adjustments			696			108,812
Net interest income			(13,637)			46,515
Gain on sales of loans			(7,739)			(23,724)
Net investor revenue			(47,226)			(64,133)
Other revenue			(3,115)			(10,166)
Total net revenue			(74,713)			(238,788)
Non-interest income
Marketplace revenue			54,635			175,993
Other non-interest income			3,115			10,166
Total non-interest income			57,750			186,159
Interest income
Interest on loans held for sale			14,916			67,579
Interest on retail and certificate loans held for investment at fair value			27,117			92,193
Interest on other loans held for investment at fair value			1,948			6,021
Interest on securities available for sale			2,754			9,930
Other interest income			38			1,021
Total interest income			46,773			176,744
Interest expense
Interest on short-term borrowings			3,179			16,332
Interest on retail notes, certificates and secured borrowings			27,117			92,193
Interest on Structured Program borrowings			3,046			11,418
Interest on other long-term debt			137			372
Total interest expense			33,479			120,315
Net interest income			13,294			56,429
Total net revenue			71,044			242,588
Provision for credit losses			(3,669)			3,800
Operating expenses
Sales and marketing			(7,201)			(65,708)
Origination and servicing			(15,595)			(54,419)
Engineering and product development			(31,984)			(109,861)
Other general and administrative			(54,332)			(169,438)
Total operating expenses			(109,112)			(399,426)
Non-interest expense
Compensation and benefits			58,649			199,991
Marketing			2,135			43,030
Equipment and software			6,430			20,931
Occupancy			6,466			22,241
Depreciation and amortization			12,348			41,832
Professional services			8,817			32,723
Other non-interest expense			14,267			38,678
Total non-interest expense			109,112			399,426
Income (Loss) before income tax expense			0			0
Income tax benefit			0			0
Consolidated net income (loss)			0			0
Reclassification Adjustments | Transaction fees | LendingClub
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Net Revenue			(24,372)			(164,489)
Reclassification Adjustments | Investor fees | LendingClub
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Net Revenue			$ (25,850)			$ (86,924)

[1] Prior period amounts have been reclassified to conform to the current period presentation. See “Notes to Condensed Consolidated Financial Statements – Note 1. Summary of Significant Accounting Policies” for additional information.

[2] Prior period amounts have been reclassified to conform to the current period presentation. See “Notes to Condensed Consolidated Financial Statements – Note 1. Summary of Significant Accounting Policies” for additional information.