Investments in and Advances to Other Real Estate Partnerships - Condensed Combined Balance Sheets (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Assets:
Net Investment in Real Estate	$ 2,101,012		$ 2,095,208
Total Assets	2,488,538		2,498,779
Liabilities:
Mortgage Loans Payable, Net	577,453		580,215
Partners’ Capital	1,097,012		1,180,722
Total Liabilities and Partners’ Capital	2,488,538		2,498,779
Carrying Value of the Operating Partnership’s Investments in Other Real Estate Partnerships	197,644		196,323
Other Real Estate Partnerships
Assets:
Net Investment in Real Estate	273,223		276,294
Note Receivable	17,023		119,364
Other Assets, Net	32,591		33,234
Total Assets	322,837		428,892
Liabilities:
Mortgage Loans Payable, Net	97,233		97,675
Other Liabilities, Net	9,765		13,795
Partners’ Capital	215,839		317,422
Total Liabilities and Partners’ Capital	322,837		428,892
Operating Partnership’s Share of Equity	214,914		316,188
Basis Differentials	(17,270)	[1]	(119,865)	[1]
Carrying Value of the Operating Partnership’s Investments in Other Real Estate Partnerships	$ 197,644		$ 196,323

[1] This amount represents the aggregate difference between the Operating Partnership’s historical cost basis and the basis reflected at the Other Real Estate Partnerships’ level. Basis differentials relate to the elimination of a note receivable and related accrued interest between a Other Real Estate Partnership and wholly owned subsidiaries of the Operating Partnership.