Credit Facilities - Narrative (Details)			3 Months Ended	6 Months Ended
	Aug. 01, 2019 USD ($) extension	Jul. 24, 2017	Mar. 31, 2019	Jun. 30, 2020 EUR (€)	Jun. 30, 2020 USD ($)	Jul. 31, 2019 USD ($)
Line of Credit Facility [Line Items]
Maximum borrowing capacity						$ 914,400,000
Maximum distribution as percentage of FFO			95.00%	95.00%
Maximum distribution as percentage of FFO, under exception			100.00%	100.00%
Maximum distribution as percentage of AFFO				105.00%
Credit Facility
Line of Credit Facility [Line Items]
Weighted-average effective interest rate				2.70%	2.70%
Credit Facility | Federal Funds
Line of Credit Facility [Line Items]
Basis spread on base rate determination		0.50%
Credit Facility | LIBOR
Line of Credit Facility [Line Items]
Basis spread on base rate determination		1.00%
Credit Facility | LIBOR | Minimum
Line of Credit Facility [Line Items]
Interest rate spread		1.60%
Credit Facility | LIBOR | Maximum
Line of Credit Facility [Line Items]
Interest rate spread		2.20%
Credit Facility | Base Rate | Minimum
Line of Credit Facility [Line Items]
Interest rate spread		0.60%
Credit Facility | Base Rate | Maximum
Line of Credit Facility [Line Items]
Interest rate spread		1.20%
Credit Facility | Revolving Credit Facility
Line of Credit Facility [Line Items]
Available for future borrowings					$ 14,200,000
Credit Facility | KeyBank National Association | Unsecured debt
Line of Credit Facility [Line Items]
Increase in aggregate commitments	$ 515,000,000.0
Total line of credit commitment	$ 1,750,000,000					$ 950,000,000.0
Credit Facility | KeyBank National Association | Unsecured debt | Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity					835,000,000.0
Number of extensions | extension	2
Extension term	6 months
Facility fee multiplier		0.0030
Credit Facility | KeyBank National Association | Unsecured debt | Revolving Credit Facility | Above Threshold
Line of Credit Facility [Line Items]
Unused capacity commitment fee		0.25%
Commitment fee percentage		50.00%
Credit Facility | KeyBank National Association | Unsecured debt | Revolving Credit Facility | Below Threshold
Line of Credit Facility [Line Items]
Unused capacity commitment fee		0.15%
Commitment fee percentage		50.00%
Credit Facility | KeyBank National Association | Unsecured debt | Term Loan Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity				€ 359,600,000	$ 403,700,000
Credit Facility Amendment
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 1,235,000,000
Credit Facility Amendment | Revolving Credit Facility | LIBOR | Minimum
Line of Credit Facility [Line Items]
Interest rate spread	1.45%
Credit Facility Amendment | Revolving Credit Facility | LIBOR | Maximum
Line of Credit Facility [Line Items]
Interest rate spread	2.05%
Credit Facility Amendment | Revolving Credit Facility | Base Rate | Minimum
Line of Credit Facility [Line Items]
Interest rate spread	0.45%
Credit Facility Amendment | Revolving Credit Facility | Base Rate | Maximum
Line of Credit Facility [Line Items]
Interest rate spread	1.05%
Credit Facility Amendment | Term Loan | LIBOR | Minimum
Line of Credit Facility [Line Items]
Interest rate spread	1.40%
Credit Facility Amendment | Term Loan | LIBOR | Maximum
Line of Credit Facility [Line Items]
Interest rate spread	2.00%
Credit Facility Amendment | Term Loan | Base Rate | Minimum
Line of Credit Facility [Line Items]
Interest rate spread	0.40%
Credit Facility Amendment | Term Loan | Base Rate | Maximum
Line of Credit Facility [Line Items]
Interest rate spread	1.00%