Real Estate Investments and Related Intangibles - Intangible Lease Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Intangible lease assets:
Intangible lease assets, net	$ 1,011,530		$ 1,037,487
Intangible lease liabilities:
Weighted-Average Useful Life	18 years 3 months 18 days
Intangible lease liabilities, net	$ 134,410		143,583
Accumulated amortization	101,968		99,315
Amortization expense	$ 748	$ 731
In-place leases and other intangible assets [Member]
Intangible lease assets:
Weighted-Average Useful Life	16 years
Intangible lease assets, net	$ 818,815		854,196
Accumulated amortization	$ 765,649		748,689
Leasing commissions [Member]
Intangible lease assets:
Weighted-Average Useful Life	7 years 9 months 18 days
Intangible lease assets, net	$ 17,524		17,808
Accumulated amortization	$ 6,093		6,027
Above-market lease assets and deferred lease incentives [Member]
Intangible lease assets:
Weighted-Average Useful Life	16 years 8 months 12 days
Intangible lease assets, net	$ 175,191		165,483
Accumulated amortization	116,628		$ 112,438
Above‑ And Below-Market Leases and Deferred Lease Incentives [Member]
Intangible lease liabilities:
Amortization expense	700	700
In-Place Leases, Leasing Commissions and Other Lease Intangibles [Member]
Intangible lease liabilities:
Amortization expense	$ 43,000	$ 33,800