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, 2014	Dec. 31, 2013	Jun. 30, 2014 Below Market Leases Net Of Above Market Leases [Member]	Jun. 30, 2013 Below Market Leases Net Of Above Market Leases [Member]	Jun. 30, 2014 Below Market Leases Net Of Above Market Leases [Member]	Jun. 30, 2013 Below Market Leases Net Of Above Market Leases [Member]	Jun. 30, 2014 Other Identified Intangible Assets [Member]	Jun. 30, 2013 Other Identified Intangible Assets [Member]	Jun. 30, 2014 Other Identified Intangible Assets [Member]	Jun. 30, 2013 Other Identified Intangible Assets [Member]	Jun. 30, 2014 Tenant Under Ground Leases [Member]	Jun. 30, 2013 Tenant Under Ground Leases [Member]	Jun. 30, 2014 Tenant Under Ground Leases [Member]	Jun. 30, 2013 Tenant Under Ground Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Gross amount	$ 522,924	$ 589,961
Accumulated amortization	(233,449)	(277,998)
Net	289,475	311,963
Gross amount	850,629	856,933
Accumulated amortization	(380,356)	(360,398)
Net	470,273	496,535
Amortization of Intangible Assets			10,480	11,000	22,162	27,177	7,375	17,098	16,700	42,311	857	1,622	1,714	2,723
2015			39,999		39,999		23,159		23,159		3,430		3,430
2016			38,377		38,377		20,223		20,223		3,430		3,430
2017			34,812		34,812		16,826		16,826		3,430		3,430
2018			33,330		33,330		12,446		12,446		3,430		3,430
2019			$ 30,093		$ 30,093		$ 11,539		$ 11,539		$ 3,430		$ 3,430