Intangible Assets (Intangibles - Future Amortization) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
2013	$ 25,245
2014	19,844
2015	13,208
2016	10,224
2017	6,652
Thereafter	14,184
Total aggregate amortization of intangible assets and liabilities	89,357
Weighted average remaining lease term (in years)
Below Market Rents [Member]
Finite-Lived Intangible Assets [Line Items]
2013	(10,477)
2014	(9,803)
2015	(8,884)
2016	(8,092)
2017	(6,050)
Thereafter	(24,160)
Total aggregate amortization of intangible assets and liabilities	(67,466)
Weighted average remaining lease term (in years)	9 years
Above Market Ground Lease [Member]
Finite-Lived Intangible Assets [Line Items]
2013	(55)
2014	(55)
2015	(55)
2016	(55)
2017	(55)
Thereafter	(2,279)
Total aggregate amortization of intangible assets and liabilities	(2,554)
Weighted average remaining lease term (in years)	49 years
Above Market Rents [Member]
Finite-Lived Intangible Assets [Line Items]
2013	2,784
2014	2,397
2015	1,717
2016	1,489
2017	997
Thereafter	2,633
Total aggregate amortization of intangible assets and liabilities	12,017
Weighted average remaining lease term (in years)	7 years
In Place Leases [Member]
Finite-Lived Intangible Assets [Line Items]
2013	32,993
2014	27,305
2015	20,430
2016	16,882
2017	11,760
Thereafter	37,990
Total aggregate amortization of intangible assets and liabilities	$ 147,360
Weighted average remaining lease term (in years)	7 years