Debt - Issuance of Senior Notes - Additional Information (Details) - USD ($)			1 Months Ended	3 Months Ended		9 Months Ended
		Jul. 09, 2020	Jul. 31, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Debt Instrument [Line Items]
Unpaid interest in accrued expenses and other current liabilities	[1]			$ 9,000,000		$ 9,000,000
Interest expense				13,000,000	$ 2,000,000	22,000,000	$ 5,000,000
2015 Credit Facility
Debt Instrument [Line Items]
Interest expense				2,000,000	$ 0	9,000,000	$ 1,000,000
7.000% senior notes due July 15, 2025
Debt Instrument [Line Items]
Debt instrument, issuance date		Jul. 09, 2020
Debt instrument, aggregate principal amount		$ 500,000,000		$ 500,000,000		$ 500,000,000
Debt instrument, interest rate		7.00%		7.00%		7.00%
Debt Instrument, date of first required payment of interest		Jan. 15, 2021
Debt Instrument, maturity date		Jul. 15, 2025
Debt instruments purchase agreement date			Jul. 07, 2020
Debt instrument, redemption, description						The Company has the option to redeem all or a portion of the Senior Notes at any time on or after July 15, 2022 at the redemption prices set forth in the Indenture, plus accrued and unpaid interest, if any. The Company may also redeem all or any portion of the Senior Notes at any time prior to July 15, 2022, at a price equal to 100% of the aggregate principal amount thereof plus a make-whole premium and accrued and unpaid interest, if any. In addition, before July 15, 2022, the Company may redeem up to 40% of the aggregate principal amount of the Senior Notes with the net proceeds of certain equity offerings at the redemption price set forth in the Indenture, provided that certain conditions are met.
Debt Instrument, redemption price, percentage of principal amount redeemed		100.00%
Debt instruments offer to purchase percentage of principal amount repurchased		101.00%
7.000% senior notes due July 15, 2025 | 2015 Credit Facility
Debt Instrument [Line Items]
Debt instrument, issuances costs				$ 10,000,000		$ 10,000,000
Outstanding debt				500,000,000		500,000,000
Unpaid interest in accrued expenses and other current liabilities				8,000,000		$ 8,000,000
Interest expense				$ 8,000,000
7.000% senior notes due July 15, 2025 | Before July 15, 2022
Debt Instrument [Line Items]
Debt instrument, redemption price, percentage		40.00%

[1] Amount relates primarily to accrued interest on our Senior Notes, and to a lesser extent commitment fees on the daily unused portion of our 2015 Credit Facility. Refer to “Note 8: Debt” for additional information.