Fair Value Measurements Cash Flow Model Critical Assumptions (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Dec. 31, 2012
Increase in investment in LLCs and other joint agreements	$ 10,543
Limited Partners' Contributed Capital	22,275
Notes Receivable, Related Parties	2,500
Capitalized Interest and Other Costs Included in Investment in Unconsolidated LLCs	$ 740	$ 800
Minimum [Member]
Equity Method Investment, Ownership Percentage	50.00%
Discount Rate Used in Determining Fair Value of Investments in Unconsolidated LLCs [Abstract]
Discount Rate Used in Determining Fair Value of Investments in Unconsolidated LLCs	13.00%
Maximum [Member]
Equity Method Investment, Ownership Percentage	61.00%
Discount Rate Used in Determining Fair Value of Investments in Unconsolidated LLCs [Abstract]
Discount Rate Used in Determining Fair Value of Investments in Unconsolidated LLCs	16.00%
2013 [Member]
Weighted Average Increase of Assumed Costs	0.00%
Weighted Average Sales Price Increase	0.00%
2014 and beyond [Member]
Weighted Average Increase of Assumed Costs	2.00%
Weighted Average Sales Price Increase	2.00%

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

+ References+ Details

For an unclassified balance sheet, amounts due from parties associated with the reporting entity as evidenced by a written promise to pay.

+ References

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

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

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Related Parties

-URI http://asc.fasb.org/extlink&oid=16382449

Reference 6: http://www.xbrl.org/2003/role/presentationRef

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Reference 7: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 8: http://www.xbrl.org/2003/role/presentationRef

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+ Details