Acquisitions (Details Textuals) (USD $)	3 Months Ended
	Mar. 31, 2013
In-Place Leases [Member]
Aquisitions (Textuals) [Abstract]
Deferred leasing costs and acquisition-related intangible assets	$ 13,000,000
Weighted average amortization period in years for deferred leasing and acquisition-related intangible assets	3 years 11 months 0 days
Above-Market Leases [Member]
Aquisitions (Textuals) [Abstract]
Deferred leasing costs and acquisition-related intangible assets	300,000
Weighted average amortization period in years for deferred leasing and acquisition-related intangible assets	4 years 7 months 0 days
Deferred Leasing Costs [Member]
Aquisitions (Textuals) [Abstract]
Deferred leasing costs and acquisition-related intangible assets	2,700,000
Weighted average amortization period in years for deferred leasing and acquisition-related intangible assets	3 years 0 months 0 days
Below Market Leases [Member]
Aquisitions (Textuals) [Abstract]
Acquisition-related intangible liabilities	1,600,000
Weighted average amortization period in years for acquisition-related liabilities	9 years 2 months 0 days
6.05% Mortgage Payable Due June 1, 2019 [Member] | Kilroy Realty, L.P. [Member] | Secured Debt [Member]
Aquisitions (Textuals) [Abstract]
Principal amount of secured debt	83,900,000
Debt premium	$ 11,600,000