Identified Intangible Assets and Intangible Liabilities (Details) (USD $) In Thousands, unless otherwise specified			3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Below Market Leases Net Of Above Market Leases [Member]	Sep. 30, 2013 Below Market Leases Net Of Above Market Leases [Member]	Sep. 30, 2014 Below Market Leases Net Of Above Market Leases [Member]	Sep. 30, 2013 Below Market Leases Net Of Above Market Leases [Member]	Sep. 30, 2014 Other Identified Intangible Assets [Member]	Sep. 30, 2013 Other Identified Intangible Assets [Member]	Sep. 30, 2014 Other Identified Intangible Assets [Member]	Sep. 30, 2013 Other Identified Intangible Assets [Member]	Sep. 30, 2014 Tenant Under Ground Leases [Member]	Sep. 30, 2013 Tenant Under Ground Leases [Member]	Sep. 30, 2014 Tenant Under Ground Leases [Member]	Sep. 30, 2013 Tenant Under Ground Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Gross amount	$ 503,993	$ 589,961
Accumulated amortization	(223,786)	(277,998)
Net	280,207	311,963
Gross amount	843,941	856,933
Accumulated amortization	(385,824)	(360,398)
Net	458,117	496,535
Amortization of Intangible Assets			10,039	11,145	32,201	38,322	6,296	10,686	22,996	52,997	858	981	2,572	3,704
2015			40,071		40,071		23,160		23,160		3,430		3,430
2016			38,455		38,455		20,195		20,195		3,430		3,430
2017			34,890		34,890		16,813		16,813		3,430		3,430
2018			33,381		33,381		12,446		12,446		3,430		3,430
2019			$ 30,105		$ 30,105		$ 11,539		$ 11,539		$ 3,430		$ 3,430