Acquired Leases Intangibles (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Finite-Lived Intangible Assets [Line Items]
Acquired lease intangible assets, net of amortization	$ 42,459		$ 27,054
Acquired lease intangible liabilities, net	20,325		12,662
Finite-Lived Intangible Assets, Amortization Expense	5,069		3,772		2,426
Weighted Average Accretion Period of Intangible Liabilities (in years)	9 years 10 months 28 days	[1]
Acquired lease intangible liability accretion	1,950	[1]	1,375	[1]	1,303	[1]
In-place leases, net
Finite-Lived Intangible Assets [Line Items]
Acquired lease intangible assets, net of amortization	31,314		21,900
Acquired Finite-lived Intangible Asset, Weighted Average Useful Life (in years)	6 years 8 months 12 days
Finite-Lived Intangible Assets, Amortization Expense	4,307		3,436		2,317
Above-market leases, net
Finite-Lived Intangible Assets [Line Items]
Acquired lease intangible assets, net of amortization	9,440		3,427
Acquired Finite-lived Intangible Asset, Weighted Average Useful Life (in years)	9 years 8 months 12 days	[2]
Finite-Lived Intangible Assets, Amortization Expense	739	[2]	319	[2]	108	[2]
Above-market ground leases, net
Finite-Lived Intangible Assets [Line Items]
Acquired lease intangible assets, net of amortization	1,705		1,727
Acquired Finite-lived Intangible Asset, Weighted Average Useful Life (in years)	84 years 6 months	[2]
Finite-Lived Intangible Assets, Amortization Expense	$ 23	[2]	$ 17	[2]	$ 1	[2]

[1] Amounts are recorded as an increase to minimum rent.

[2] Amounts are recorded as a reduction to minimum rent.