Description of Business and Basis of Presentation (Recently Issued Accounting Standards) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total rental property revenues	$ 475,212	$ 466,185	$ 259,211
Capitalized indirect leasing costs	3,800
Cumulative effect of change in accounting principle		22,329
Distributions in Excess of Cumulative Net Income
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principle		22,329
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right of use asset	40,000
Lease liability	40,000
Accounting Standards Update 2017-05 | Distributions in Excess of Cumulative Net Income
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principle		22,300
Rental Property
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total rental property revenues	461,853	446,035	249,814
Fee and Other Revenue
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total rental property revenues	$ 13,400	$ 20,200	$ 9,400