Intangible Assets and Liabilities (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Amortizable intangible assets
Acquired finite-lived intangible asset, amount	$ 196,334
Acquired finite-lived intangible liabilities, amount	(56,978)
In-place lease
Amortizable intangible assets
Weighted average useful life	10 years 7 months 6 days
Acquired finite-lived intangible asset, amount	180,060
Above-market rent
Amortizable intangible assets
Weighted average useful life	16 years 2 months 12 days
Acquired finite-lived intangible asset, amount	14,864
Below-market ground lease
Amortizable intangible assets
Weighted average useful life	94 years 4 months 24 days
Acquired finite-lived intangible asset, amount	1,410
Below-market rent
Amortizable intangible assets
Weighted average useful life	8 years 8 months 12 days
Acquired finite-lived intangible liabilities, amount	$ (56,978)