Investments in Real Estate and Real Estate Under Construction - Summary of development arrangements outstanding (Details) ft² in Thousands, $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($) ft²
Investments in Real Estate and Real Estate Under Construction [Line Items]
Square Feet (000's) | ft²	760
Opelika, Alabama [Member] | Industrial Property [Member]
Investments in Real Estate and Real Estate Under Construction [Line Items]
Square Feet (000's) | ft²	165
Maximum Commitment/Estimated Completion Cost | $	$ 37,370
Lease Term (Years)	25 years
Investment in real estate under construction | $	$ 29,442