Identified Intangible Assets and Intangible Liabilities (Details) (USD $) In Thousands, unless otherwise specified			3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 Below Market Leases Net Of Above Market Leases [Member]	Mar. 31, 2013 Below Market Leases Net Of Above Market Leases [Member]	Mar. 31, 2014 Other Identified Intangible Assets [Member]	Mar. 31, 2013 Other Identified Intangible Assets [Member]	Mar. 31, 2014 Tenant Under Ground Leases [Member]	Mar. 31, 2013 Tenant Under Ground Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Gross amount	$ 589,973	$ 589,961
Accumulated amortization	(290,214)	(277,998)
Net	299,759	311,963
Gross amount	850,765	856,933
Accumulated amortization	(367,972)	(360,398)
Net	482,793	496,535
Amortization of Intangible Assets			11,682	16,177	9,325	25,213	858	1,102
2015			39,972		23,254		3,430
2016			38,631		20,237		3,430
2017			34,929		16,821		3,430
2018			33,309		12,441		3,430
2019			$ 30,072		$ 11,535		$ 3,430