Real Estate Investments and Related Intangibles - Intangible Lease Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Intangible lease assets:
Intangible lease assets, net	$ 931,832		$ 928,844
Intangible lease liabilities:
Weighted-Average Useful Life	19 years 9 months 18 days
Intangible lease liabilities, net	$ 117,121		120,938
Accumulated amortization	108,537		106,504
Amortization expense	$ 1,547	$ 748
In-place leases and other intangible assets [Member]
Intangible lease assets:
Weighted-Average Useful Life	17 years
Intangible lease assets, net	$ 723,695		745,026
Accumulated amortization	$ 815,131		810,597
Leasing commissions [Member]
Intangible lease assets:
Weighted-Average Useful Life	9 years 2 months 12 days
Intangible lease assets, net	$ 16,536		16,042
Accumulated amortization	$ 8,013		7,565
Above-market lease assets and deferred lease incentives [Member]
Intangible lease assets:
Weighted-Average Useful Life	23 years 7 months 6 days
Intangible lease assets, net	$ 191,601		167,776
Accumulated amortization	128,850		$ 125,455
Above‑ And Below-Market Leases and Deferred Lease Incentives [Member]
Intangible lease liabilities:
Amortization expense	1,500	700
In-Place Leases, Leasing Commissions and Other Lease Intangibles [Member]
Intangible lease liabilities:
Amortization expense	$ 29,200	$ 43,000