Debt - Senior Secured Credit Facilities (Details) - USD ($)					1 Months Ended				3 Months Ended		9 Months Ended	12 Months Ended
	Feb. 20, 2020	Nov. 19, 2019	May 15, 2019	Feb. 05, 2018	Jan. 31, 2020	Feb. 28, 2019	Feb. 28, 2018	Dec. 31, 2017	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Oct. 31, 2017
Debt Instrument [Line Items]
Debt to adjusted asset ratio			0.65
Permitted acquisitions consummated			0.70
EBITDA to interest charges			2.00
Restricted net assets												$ 7,900,000,000
Proceeds from follow-on offering of common stock		$ 694,200,000		$ 1,300,000,000
Loss on extinguishment of debt										$ 38,488,000		$ 58,143,000	$ 23,040,000
Term Loan B Facility
Debt Instrument [Line Items]
Debt instrument, face amount								$ 2,200,000,000		$ 2,200,000,000				$ 2,200,000,000
Senior Notes
Debt Instrument [Line Items]
Percentage of cash dividends of adjusted total assets to be distributed												0.60%
Amount of cash dividends of adjusted total assets to be distributed												$ 30,000,000
Percentage of cash dividends of real estate taxable income to be distributed												100.00%
Amount of cash dividends of funds from operations to be distributed												$ 30,000,000
Cumulative adjusted funds from operations rate												95.00%
Percentage of principal amount redeemed (up to)												60.00%
Senior Notes | Term Loan B Facility | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate												2.00%	2.25%
Senior Notes | Second Lien Notes
Debt Instrument [Line Items]
Interest rate, stated percentage								8.00%		8.00%		8.00%		8.00%
Repayments of debt						$ 537,500,000
Redemption price, percentage (equal to)						100.00%					108.00%	108.00%
Loss on extinguishment of debt						$ 39,000,000.0
Senior Notes | Second Lien Notes | Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Debt instrument, applicable premium percentage												104.00%
Redemption price, percentage (equal to)												100.00%
Senior Notes | Second Lien Notes | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Debt instrument, applicable premium percentage												100.00%
Redemption price, percentage (equal to)												104.00%
Senior Notes | Secured Notes Maturing in 2023
Debt Instrument [Line Items]
Debt instrument, face amount												$ 498,500,000			$ 766,900,000
Interest rate, stated percentage															8.00%
Percentage of principal amount redeemed (up to)											35.00%	35.00%
Loss on extinguishment of debt									$ 23,000,000.0
Amount redeemed							$ 268,400,000
Revolving Credit Facility
Debt Instrument [Line Items]
Debt instrument, face amount			$ 1,200,000,000					$ 400,000,000.0		$ 400,000,000.0				$ 400,000,000.0
Debt to adjusted asset ratio			0.75
Percentage of utilization of credit facility			30.00%
Revolving Credit Facility | Minimum
Debt Instrument [Line Items]
Interest rate, stated percentage			0.375%
Revolving Credit Facility | Maximum
Debt Instrument [Line Items]
Interest rate, stated percentage			0.50%
Revolving Credit Facility | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate			1.75%
Revolving Credit Facility | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate			2.00%
Revolving Credit Facility | Base Rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate			0.75%
Revolving Credit Facility | Base Rate | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate			1.00%
Revolving Credit Facility | Term Loan B Facility
Debt Instrument [Line Items]
Debt instrument, face amount								$ 300,000,000.0		$ 300,000,000.0				$ 300,000,000.0
Proceeds from follow-on offering of common stock							1,300,000,000
Repayments of debt							$ 100,000,000.0
Percentage of amortization of principal amount per annum							1.00%
Revolving Credit Facility | Term Loan B Facility | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate			1.75%	2.00%				2.25%					2.25%	2.25%
Revolving Credit Facility | Term Loan B Facility | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate			1.75%
Revolving Credit Facility | Term Loan B Facility | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate			2.00%
Revolving Credit Facility | Term Loan B Facility | Base Rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate			0.75%
Revolving Credit Facility | Term Loan B Facility | Base Rate | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate			1.00%
Revolving Credit Facility | Amended And Rested Credit Agreement
Debt Instrument [Line Items]
Percentage of funds from operations												95.00%
Percentage of cash dividends of adjusted total assets to be distributed												0.60%
Amount of cash dividends of adjusted total assets to be distributed												$ 30,000,000
Revolving Credit Facility | Senior Notes
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity			$ 600,000,000								$ 1,000,000,000.0	$ 1,000,000,000.0
Revolving Credit Facility | Senior Notes | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate												2.00%	2.25%
Subsequent Event | Senior Notes | Second Lien Notes
Debt Instrument [Line Items]
Repayments of debt	$ 498,500,000
Redemption price, percentage (equal to)	100.00%
Subsequent Event | Revolving Credit Facility | Term Loan B Facility | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate					1.75%
Subsequent Event | Revolving Credit Facility | Term Loan B Facility | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate					2.00%