Investments in Unconsolidated Real Estate Entities - Schedule of Operation - Mixed-Use LP (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended			9 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Sep. 24, 2010 Mixed-Use LP [Member]
Real Estate Properties [Line Items]
Revenues				$ 90
Expenses				(1,648)
Gain on distribution of assets / liabilities at fair value				20,049
Net income				18,491
Company's share of net income (loss)	$ 7,995	$ 1,001	$ 18,739	$ 18,104