Real Estate Investments (Summary of Future Amortization Expense) (Details) $ in Thousands	Dec. 31, 2018 USD ($)
Depreciation and Amortization
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, amortization expense - 2019	$ 9,675
Finite-lived intangible assets, amortization expense - 2020	7,924
Finite-lived intangible assets, amortization expense - 2021	6,486
Finite-lived intangible assets, amortization expense - 2022	4,871
Finite-lived intangible assets, amortization expense - 2023	3,632
Depreciation and Amortization | In-place leases
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, amortization expense - 2019	8,510
Finite-lived intangible assets, amortization expense - 2020	6,759
Finite-lived intangible assets, amortization expense - 2021	5,549
Finite-lived intangible assets, amortization expense - 2022	4,163
Finite-lived intangible assets, amortization expense - 2023	2,924
Depreciation and Amortization | Other intangibles
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, amortization expense - 2019	1,165
Finite-lived intangible assets, amortization expense - 2020	1,165
Finite-lived intangible assets, amortization expense - 2021	937
Finite-lived intangible assets, amortization expense - 2022	708
Finite-lived intangible assets, amortization expense - 2023	708
Rental Income
Finite-Lived Intangible Assets [Line Items]
Below market lease, amortization income - 2019	(3,082)
Below market lease, amortization income - 2020	(2,669)
Below market lease, amortization income - 2021	(2,339)
Below market lease, amortization income - 2022	(1,798)
Below market lease, amortization income - 2023	(1,597)
Amortization income to be included in rental income - 2019	(1,799)
Amortization income to be included in rental income - 2020	(1,505)
Amortization income to be included in rental income - 2021	(1,248)
Amortization income to be included in rental income - 2022	(924)
Amortization income to be included in rental income - 2023	(872)
Rental Income | Above-market lease assets
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, amortization expense - 2019	1,283
Finite-lived intangible assets, amortization expense - 2020	1,164
Finite-lived intangible assets, amortization expense - 2021	1,091
Finite-lived intangible assets, amortization expense - 2022	874
Finite-lived intangible assets, amortization expense - 2023	$ 725