Real Estate Investments (Acquired Leases) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	$ 448,175	$ 413,948
Finite-lived intangible assets, accumulated amortization	159,626	143,401
Intangible assets, net	288,549	270,547
Finite-lived intangible liabilities, gross	106,435	107,486
Finite-lived intangible liabilities, accumulated amortization	22,394	17,548
Intangible liabilities, net	84,041	89,938
Below market lease, gross	106,435	107,401
Below market lease, accumulated amortization	22,394	17,543
Below market lease, net	84,041	89,858
In-place leases
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	424,509	388,323
Finite-lived intangible assets, accumulated amortization	151,474	135,864
Intangible assets, net	273,035	252,459
Above-market lease assets
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	23,666	24,392
Finite-lived intangible assets, accumulated amortization	8,152	7,477
Intangible assets, net	15,514	16,915
Below-market ground lease asset
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	0	1,233
Finite-lived intangible assets, accumulated amortization	0	60
Intangible assets, net	0	1,173
Above-market ground lease liability [1]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible liabilities, gross	0	85
Finite-lived intangible liabilities, accumulated amortization	0	5
Intangible liabilities, net	$ 0	$ 80