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Stock-Based Compensation - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended	21 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant	11,578,219		11,578,219			11,578,219
Shares granted			2,411,345
Shares granted, weighted average grant date fair value			$ 11.62
Unrecognized compensation cost relating to unvested restricted stock	$ 69,500,000		$ 69,500,000			$ 69,500,000
Unrecognized compensation cost relating to unvested restricted stock, recognition period (in years)			2 years 10 months 24 days
Four Zero One K Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employer Discretionary Contribution Amount	1,500,000		$ 4,500,000
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted			2,411,345	2,022,198
Shares granted, weighted average grant date fair value			$ 11.62	$ 10.44
Compensation and benefits expense	7,500,000	$ 7,700,000	$ 22,800,000	$ 23,200,000
Restricted Stock \| Share-based Payment Arrangement, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted, vesting period			3 years	3 years
Restricted Stock \| Share-based Payment Arrangement, Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted, vesting period			5 years	5 years
Performance-Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted			446,181		418,674	864,855
Compensation and benefits expense	$ 863,000,000	$ 411,000,000	$ 1,800	$ 689,000,000
Vesting rights, description			Included in this total are 446,181 shares granted during the nine months ended September 30, 2020, which have a performance period of January 1, 2020 to December 31, 2022 and vest on April 1, 2023, subject to adjustment or forfeiture, based upon the achievement by the Company of certain performance standards The Company granted 418,674 PSUs during 2019, which have a performance period of January 1, 2019 to December 31, 2021 and vest on April 1, 2022, subject to adjustment or forfeiture, based upon the achievement by the Company of certain performance standards.