Investment in Office Properties and Parking Properties - Business Combination Pro Forma (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Business Combinations [Abstract]
Revenues	$ 113,594	$ 110,186	$ 331,118	$ 321,185
Net loss attributable to common stockholders	$ (615)	$ (596)	$ (990)	$ (960)
Basic net loss attributable to common stockholders (in dollars per share)	$ (0.01)	$ (0.01)	$ (0.01)	$ (0.01)
Diluted net loss attributable to common stockholders (in dollars per share)	$ (0.01)	$ (0.01)	$ (0.01)	$ (0.01)

The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(2)-(3)

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1392-128463

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The pro forma diluted net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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