Investments in Real Estate - Dispositions (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($) ft²	Mar. 31, 2016 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gains on sale of real estate	$ 2,668	$ 0
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Archibald Ave
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Rentable square feet | ft²	62,677
Contractual Sales Price	$ 6,875
Gains on sale of real estate	$ 2,668