The value (monetary amount) of the award the plaintiff seeks in the legal matter.

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Commitments and Contingencies (Details Textual) (USD $)	12 Months Ended
Commitments and Contingencies (Details Textual) (USD $)	Dec. 31, 2011 CoinvestmentVenture	Dec. 31, 2009	Dec. 31, 2010
Commitments and Contingencies (Textual) [Abstract]
Outstanding performance and surety bonds	$ 27,600,000		$ 38,100,000
Guaranteed Debt	6,900,000
Settlement cost of previous acquisition		13,000,000
Previous acquisition settlement liability	7,800,000
Number of unconsolidated co-investment venture	1
Potential future legal settlement	600,000
Total damages	$ 200,000,000
Maximum [Member]
Operating Leased Assets [Line Items]
Operating leases lease term	61 years
Minimum [Member]
Operating Leased Assets [Line Items]
Operating leases lease term	1 year