Investment in Unconsolidated Joint Ventures (MSREF/Cousins Terminus 200 LLC) (Details) (MSREF Terminus Two Hundred LLC [Member])	Dec. 31, 2012 sqft
Schedule of Equity Method Investments [Line Items]
Square footage of real estate property (square feet)	566,000
Equity Method Investment, Ownership Percentage	20.00%
Morgan Stanley [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	80.00%

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 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

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant