Impairment of Real Estate, Impairment of Unconsolidated Entities and Write-Off of Abandoned Development Projects and Demolition Costs (Details) (USD $)	11 Months Ended		12 Months Ended		2 Months Ended	11 Months Ended	12 Months Ended		11 Months Ended	12 Months Ended		11 Months Ended	12 Months Ended		11 Months Ended	12 Months Ended		11 Months Ended	12 Months Ended		11 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Jan. 31, 2013	Jan. 31, 2012	Dec. 31, 2013 Brooklyn Atlantic Yards [Member]	Dec. 31, 2013 Brooklyn Atlantic Yards [Member]	Jan. 31, 2013 Brooklyn Atlantic Yards [Member]	Jan. 31, 2012 Brooklyn Atlantic Yards [Member]	Dec. 31, 2013 LiveWork Las Vegas [Member]	Jan. 31, 2013 LiveWork Las Vegas [Member]	Jan. 31, 2012 LiveWork Las Vegas [Member]	Dec. 31, 2013 Promenade Bolingbrook [Member]	Jan. 31, 2013 Promenade Bolingbrook [Member]	Jan. 31, 2012 Promenade Bolingbrook [Member]	Dec. 31, 2013 Building J at Illinois Science and Technology Park [Member]	Jan. 31, 2013 Building J at Illinois Science and Technology Park [Member]	Jan. 31, 2012 Building J at Illinois Science and Technology Park [Member]	Dec. 31, 2013 Halle Building [Member]	Jan. 31, 2013 Halle Building [Member]	Jan. 31, 2012 Halle Building [Member]	Dec. 31, 2013 Other [Member]	Jan. 31, 2013 Other [Member]	Jan. 31, 2012 Other [Member]
Schedule of Impairment of Real Estate [Line Items]
Impairment of real estate	$ 475,555,000	$ 30,660,000	$ 30,660,000	$ 235,000	$ 289,864,000	$ 289,864,000	$ 0	$ 0	$ 112,838,000	$ 0	$ 0	$ 54,194,000	$ 0	$ 0	$ 17,474,000	$ 0	$ 0	$ 0	$ 30,200,000	$ 0	$ 1,185,000	$ 460,000	$ 235,000