Investments - Intangible Lease Assets and Real Estate Investments (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) property item Options	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)
Accounting for Real Estate Investments
Remaining noncancelable lease term	14 years
Number of real estate properties vacant not subject to lease | property	12
Future minimum rentals to be received under the remaining noncancelable term of the operating leases
Remainder of 2020	$ 513,746
2021	684,042
2022	684,536
2023	682,645
2024	680,091
2025	674,896
Thereafter	5,705,400
Total future minimum rentals	$ 9,625,356
Term of renewal options	5 years
Intangible lease assets	$ 72,190		$ 73,366
Accumulated amortization	(29,970)		(28,948)
Net intangible lease assets	42,220		44,418
Amortization in the next five years
Remainder of 2020	3,000
2021	3,800
2022	3,700
2023	3,300
2024	2,700
2025	$ 2,200
Minimum
Future minimum rentals to be received under the remaining noncancelable term of the operating leases
Typical number of renewal options | item	1
Number of renewal periods at the option of the Company | Options	2
Maximum
Future minimum rentals to be received under the remaining noncancelable term of the operating leases
Number of renewal periods at the option of the Company | Options	4
Decrease to rental revenue
Amortization in the next five years
Remainder of 2020	$ 800
2021	600
2023	400
2024	400
2025	400
Amortization expense
Future minimum rentals to be received under the remaining noncancelable term of the operating leases
Amount amortized	1,100	$ 1,700
In -place leases
Future minimum rentals to be received under the remaining noncancelable term of the operating leases
Intangible lease assets	$ 43,249		44,425
Amortization in the next five years
Weighted average remaining amortization period	8 years
Ground lease interests
Future minimum rentals to be received under the remaining noncancelable term of the operating leases
Intangible lease assets	$ 19,449		19,449
Amortization in the next five years
Weighted average remaining amortization period	44 years
Above-market leases
Future minimum rentals to be received under the remaining noncancelable term of the operating leases
Intangible lease assets	$ 9,492		$ 9,492
Amortization in the next five years
Weighted average remaining amortization period	6 years
Above-market leases | Decrease to rental revenue
Future minimum rentals to be received under the remaining noncancelable term of the operating leases
Amount amortized	$ 300	$ 300