Acquisitions Allocation of Purchase Price (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Acquired Finite-Lived Intangible Assets [Line Items]
Land	$ 36,815
Buildings and garages	148,206
Tenant improvements	18,455
Lease commissions	8,272
Lease in place value	18,075
Above market leases	2,936
Below market leases	$ (5,735)
Lease commisions [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average life (in years)	6 years 0 months 0 days
Leases, Acquired-in-Place [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average life (in years)	5 years 0 months 0 days
Above Market Leases [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average life (in years)	4 years 0 months 0 days
Below Market Leases [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average life (in years)	7 years 0 months 0 days
Building [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average life (in years)	40 years 0 months 0 days
Building Improvements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average life (in years)	6 years 0 months 0 days