Real Estate Investments - Summary of Office Properties Sold (Parenthetical) (Details) - Office Properties [Member] $ in Millions		3 Months Ended
	Feb. 04, 2016 property	Mar. 31, 2016 property		Dec. 31, 2015 USD ($)
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold		59
Och Ziff Portfolio [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold	58	58	[1]
Provision for impairment on assets held for sale | $				$ 45.4

[1] Exhibit 99.2 to Form 8-K filed on February 10, 2016 contains a complete list of the 58 properties. See also Note 4, "Investment in Unconsolidated Real Estate Ventures," for further details of the transactions.