Subsequent Events - Narrative (Details) - Disposed of by Sale $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
	Apr. 30, 2017 USD ($) ft² building property	Mar. 31, 2017 USD ($) ft² building	Dec. 31, 2016 USD ($) ft² building property
Subsequent Event [Line Items]
Number of properties sold | property			30
Number of buildings sold | building		3	62
Square footage (in sqft) | ft²		827,204	8,000,000
Gross sales price		$ 113,125	$ 1,300,000
Subsequent event
Subsequent Event [Line Items]
Number of properties sold | property	2
Number of buildings sold | building	5
Square footage (in sqft) | ft²	630,326
Gross sales price	$ 64,500
Subsequent event | Parkshore Plaza
Subsequent Event [Line Items]
Mortgage debt repaid at par	$ 41,300