Investment in Office Properties Allocation of Purchase Price (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014
Acquired Finite-Lived Intangible Assets [Line Items]
Land	$ 5,376
Buildings and garages	21,494
Tenant improvements	3,597
Lease commissions	1,021
Lease in place value	2,268
Above market leases	260
Below market leases	$ (766)
Weighted average life of below market lease (in years)	7 years 0 months 0 days
Lease commisions
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average life of intangibles (in years)	4 years
Leases, Acquired-in-Place
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average life of intangibles (in years)	4 years
Above Market Leases
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average life of intangibles (in years)	4 years 0 months 0 days
Building
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average life assets (in years)	40 years 0 months 0 days
Building Improvements
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average life assets (in years)	5 years