Investment in Unconsolidated Joint Ventures (CP Venture LLC Entities) (Details) (CP Venture Two LLC entities [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012
Schedule of Equity Method Investments [Line Items]
Ownership percentage equity method investment (percent)	10.40%
Company's share of gain on sale of equity investee property	$ 167
Cash balance of joint venture	$ 2,300
Office Building [Member]
Schedule of Equity Method Investments [Line Items]
Square footage of real estate property (square feet)	69,000
Retail [Member]
Schedule of Equity Method Investments [Line Items]
Number of real estate properties owned by venture (properties)	3
Square footage of real estate property (square feet)	934,000

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 159

-Paragraph 18

-Subparagraph f

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 18

-Paragraph 20

-Subparagraph a (1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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