Temporary Equity - Narrative (Details) $ / shares in Units, $ in Thousands			1 Months Ended			3 Months Ended		9 Months Ended
	May 28, 2021 USD ($) $ / shares shares	May 29, 2019 USD ($)	Apr. 30, 2021 USD ($) shares	Dec. 31, 2020 USD ($) $ / shares shares	May 31, 2020 USD ($) shares	Sep. 30, 2021 USD ($) $ / shares shares	Sep. 30, 2020 USD ($) shares	Sep. 30, 2021 USD ($) $ / shares shares	Sep. 30, 2020 USD ($) shares	Jun. 30, 2021 shares	Jun. 30, 2020 shares	Dec. 31, 2019 shares
Temporary Equity [Line Items]
Preferred stock, shares authorized (in shares)	100,000,000
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.0001
Redeemable preferred stock, shares authorized (in shares)	100,000,000			570,562,965		100,000,000		100,000,000
Redeemable preferred stock, par value (in dollars per share) | $ / shares	$ 0.0000025			$ 0.00		$ 0.00		$ 0.00
Number of shares converted (in shares)	465,832,666
Redemption of redeemable preferred stock (in shares)	15,000,000
Exchange ratio	1.7428
Redeemable preferred stock, shares outstanding (in shares)				469,150,522		3,234,000	496,091,785	3,234,000	496,091,785	3,234,000	496,091,785	404,170,765
Redeemable preferred stock, shares issued (in shares)				469,150,522		3,234,000		3,234,000
Value of shares redeemed and canceled | $	$ 150,000
Issuance of redeemable preferred stock in acquisition (in shares)									91,921,020
Issuance of redeemable preferred stock in acquisition | $									$ 814,156
Dividends payable | $				$ 0		$ 10,189		$ 10,189
Redemption amount | $				$ 3,210,470		$ 323,400		323,400
Sale of stock, price per share (in dollars per share) | $ / shares	$ 10.00
Warrant Liability
Temporary Equity [Line Items]
Reclassification to permanent equity in conjunction with the Business Combination | $	$ 161,775							$ 161,775
Warrant To Purchase Series H Redeemable Preferred Stock
Temporary Equity [Line Items]
Number of warrants issued (in shares)												12,170,990
Galileo Financial Technologies, Inc.
Temporary Equity [Line Items]
Adjustment to reduce initial consideration transferred amount | $			$ 743
Series 1
Temporary Equity [Line Items]
Redeemable preferred stock, shares authorized (in shares)	4,500,000
Redeemable preferred stock, shares outstanding (in shares)						3,234,000		3,234,000
Redeemable preferred stock, shares issued (in shares)						3,234,000		3,234,000
Issuance of redeemable preferred stock in acquisition | $		$ 320,400
Special distribution | $	$ 21,200
Dividend rate (in dollars per share) | $ / shares	$ 12.50
Temporary equity, dividend rate percentage	12.50%
Redeemable preferred stock, original issuance price (in dollars per share) | $ / shares	$ 100.00
Temporary equity, dividend rate spread percentage	9.94%
Dividends | $						$ 10,189	$ 10,189	$ 30,236	$ 30,346
Temporary equity, redemption value | $	$ 323,400
Series F
Temporary Equity [Line Items]
Exchange ratio	1.1102
Number of shares called and redeemed (in shares)				6,338,696
Series G
Temporary Equity [Line Items]
Exchange ratio	1.2093
Series H
Temporary Equity [Line Items]
Exchange ratio	1.0863
Issuance of redeemable preferred stock in acquisition | $		193,900
Preferred Stock
Temporary Equity [Line Items]
Redeemable preferred stock, shares outstanding (in shares)						0		0
Redeemable preferred stock, shares issued (in shares)						0		0
Redeemable Preferred Stock
Temporary Equity [Line Items]
Number of shares called and redeemed (in shares)				26,941,262
Value of shares called and redeemed | $				$ 80,201
Series B
Temporary Equity [Line Items]
Number of shares called and redeemed (in shares)				18,400,928
Series D
Temporary Equity [Line Items]
Number of shares called and redeemed (in shares)				1,816,803
Series E
Temporary Equity [Line Items]
Number of shares called and redeemed (in shares)				384,835
Series H-1 | Galileo Financial Technologies, Inc.
Temporary Equity [Line Items]
Issuance of redeemable preferred stock in acquisition (in shares)					91,921,020
Issuance of redeemable preferred stock in acquisition | $					$ 814,156
Adjustment to reduce initial consideration transferred amount, equivalent number of shares issued (in shares)			83,856
Series H warrants
Temporary Equity [Line Items]
Proceeds allocated from issuance of warrants | $		22,300
Series 1 and Series H Redeemable Preferred Stock
Temporary Equity [Line Items]
Issuance of redeemable preferred stock in acquisition | $		539,000
Proceeds from issuance, remaining amount allocated | $		$ 514,300
Common Stock | Common Stock Transaction
Temporary Equity [Line Items]
Sale of stock, price per share (in dollars per share) | $ / shares				$ 10.57