Real Estate Investments - Summary of Land Parcels Sold (Parenthetical) (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
		Dec. 31, 2015	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain (Loss) on Sale			$ 116,983		$ 20,496		$ 4,901
Greenhills Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Provision for impairment on assets held for sale					300
Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain (Loss) on Sale			9,232	[1]	3,019	[2]	$ 1,184	[3]
Land [Member] | Greenhills Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain (Loss) on Sale	[1],[4]		$ 0
Provision for impairment on assets held for sale		$ 300
Land [Member] | Two Christina Centre [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain (Loss) on Sale	[2],[5]				$ 0
Provision for impairment on assets held for sale		$ 300

[1] Gain on Sale is net of closing and other transaction related costs.

[2] Gain/(Loss) on sale includes closing and other transaction related costs.

[3] Gain/(Loss) on Sale is net of closing and other transaction related costs.

[4] The carrying value of the land exceeded the fair value less the anticipated costs of sale as of December 31, 2015, therefore the Company recognized an impairment loss of $0.3 million during the three-month period ended December 31, 2015. There was no gain or loss recognized on the sale during 2016.

[5] The Company recorded an impairment loss of $0.3 million for Two Christina Centre during the fourth quarter of 2015. As such, there was no gain/(loss) at disposition for this land parcel.