Summary of Significant Accounting Policies - Business Overview/Segment Reporting (Details) $ in Thousands, ft² in Millions	9 Months Ended
	Sep. 30, 2017 USD ($) ft² state reporting_unit real_estate_property
Accounting Policies [Abstract]
General partner ownership	100.00%
Value of real estate property investments and mortgages | $	$ 358,047
Number of real estate properties | real_estate_property	80
Number of states in which real estate investments are in | state	26
Area of real estate property (in square feet) | ft²	1.8
Number of reporting units | reporting_unit	1