Investments - Schedule of Lease Intangible Assets and Liabilities, Net of Accumulated Amortization (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Lessor, Lease, Description [Line Items]
Less: accumulated amortization	$ (170,261)	$ (167,539)
Intangible lease assets, net	381,398	385,079
Below-market leases	174,965	176,816
Less: accumulated amortization	(50,868)	(49,481)
Intangible lease liabilities, net	124,097	127,335
In-place leases
Lessor, Lease, Description [Line Items]
Intangible lease assets, gross	454,363	457,616
Above-market leases
Lessor, Lease, Description [Line Items]
Intangible lease assets, gross	$ 97,296	$ 95,002