Real Estate Investments - Summary of Land Parcels Sold (Details) $ in Thousands		3 Months Ended
		Mar. 31, 2017 USD ($) a Parcel	Mar. 31, 2016 USD ($)
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from the sale of properties		$ 74,159	$ 704,911
Gain on Sale		$ 7,323	$ 115,456
Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel		2
Acreage of land | a		6.5
Sales Price		$ 4,600
Proceeds from the sale of properties		4,320
Gain on Sale		$ 0
Gateway L and C [Member] | Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel		1
Acreage of land | a		4.8
Sales Price		$ 1,100
Proceeds from the sale of properties		1,043
Gain on Sale	[1]	$ 0
Garza Ranch [Member] | Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel		1
Acreage of land | a		1.7
Sales Price		$ 3,500
Proceeds from the sale of properties		3,277
Gain on Sale	[2]	$ 0

[1] During the fourth quarter of 2016, the Company recognized a nominal impairment related to this land parcel.

[2] The Company has a continuing involvement through a completion guaranty, which requires the Company as developer to complete certain infrastructure improvements on behalf of the buyers of the land parcels. The cash received at settlement was recorded as “Deferred income, gains and rent” on the Company’s consolidated balance sheet and the Company will recognize the sale once the infrastructure improvements are complete.