Real Estate Properties - Summary of Properties Held for Sale (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($) ft² building property	Dec. 31, 2015 property
Real Estate Properties [Line Items]
Number of Properties		0
Held-for-sale
Real Estate Properties [Line Items]
Number of Properties	2
Number of Buildings | building	2
Square Footage (in sqft) | ft²	191,150
Gross Sales Price | $	$ 46,700
Held-for-sale | 1525 Locust Street
Real Estate Properties [Line Items]
Number of Properties	1
Number of Buildings | building	1
Square Footage (in sqft) | ft²	98,009
Gross Sales Price | $	$ 17,700
Held-for-sale | 633 Ahua Street
Real Estate Properties [Line Items]
Number of Properties	1
Number of Buildings | building	1
Square Footage (in sqft) | ft²	93,141
Gross Sales Price | $	$ 29,000