Identified Intangible Assets and Intangible Liabilities (Details) (USD $) In Thousands, unless otherwise specified			3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2013 Below Market Leases Net Of Above Market Leases [Member]	Jun. 30, 2012 Below Market Leases Net Of Above Market Leases [Member]	Jun. 30, 2013 Below Market Leases Net Of Above Market Leases [Member]	Jun. 30, 2012 Below Market Leases Net Of Above Market Leases [Member]	Jun. 30, 2013 Other Identified Intangible Assets [Member]	Jun. 30, 2012 Other Identified Intangible Assets [Member]	Jun. 30, 2013 Other Identified Intangible Assets [Member]	Jun. 30, 2012 Other Identified Intangible Assets [Member]	Jun. 30, 2013 Tenant Under Ground Leases [Member]	Jun. 30, 2012 Tenant Under Ground Leases [Member]	Jun. 30, 2013 Tenant Under Ground Leases [Member]	Jun. 30, 2012 Tenant Under Ground Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Identified intangible assets (included in other assets): Gross	$ 654,964	$ 753,022
Identified intangible assets, accumulated amortization	(365,854)	(346,664)
Finite-Lived Intangible Assets, Net, Total	289,110	406,358
Identified intangible liabilities (included in deferred credit): Gross	816,671	902,525
Identified intangible liabilities (included in deferred credit): Accumulated amortization	(363,687)	(341,536)
Identified intangible liabilities (included in deferred credit): Net	452,984	560,989
Amortization of Intangible Assets			11,672	12,570	28,506	26,313	16,992	12,807	42,086	24,024	1,622	312	2,723	582
2014			41,069		41,069		27,533		27,533		3,921		3,921
2015			38,263		38,263		22,369		22,369		3,921		3,921
2016			36,321		36,321		19,189		19,189		3,921		3,921
2017			30,936		30,936		16,029		16,029		3,921		3,921
2018			$ 29,171		$ 29,171		$ 11,830		$ 11,830		$ 3,921		$ 3,921