Investments in and Advances to Other Real Estate Partnerships - Condensed Combined Balance Sheets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011	Dec. 31, 2010
Assets:
Net Investment in Real Estate	$ 2,095,208		$ 2,124,526
Total Assets	2,498,779		2,503,882
Liabilities:
Mortgage Loans Payable, Net	580,215		656,329
Partners’ Capital	1,180,722		1,155,151		1,081,992	901,303
Total Liabilities and Partners’ Capital	2,498,779		2,503,882
Carrying Value of the Operating Partnership’s Investments in Other Real Estate Partnerships	196,323		178,104
Other Real Estate Partnerships
Assets:
Net Investment in Real Estate	276,294		264,284
Note Receivable	119,364		142,982
Other Assets, Net	33,234		34,476
Total Assets	428,892		441,742
Liabilities:
Mortgage Loans Payable, Net	97,675		107,287
Other Liabilities, Net	13,795		11,570
Partners’ Capital	317,422		322,885
Total Liabilities and Partners’ Capital	428,892		441,742
Operating Partnership’s Share of Equity	316,188		321,663
Basis Differentials	(119,865)	[1]	(143,559)	[1]
Carrying Value of the Operating Partnership’s Investments in Other Real Estate Partnerships	$ 196,323		$ 178,104

[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.