Impairment Charges (Details 1) (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Impairment Charges measured at Fair Value on a non-recurring basis
Unconsolidated joint venture investments, losses	$ 560,000	$ 35,000
Fair Value, Measurements, Nonrecurring [Member]
Impairment Charges measured at Fair Value on a non-recurring basis
Long-lived assets - held and used and held for sale	28,700,000
Fair value of assets measured on non recurring basis Losses	17,300,000
Unconsolidated joint venture investments, fair value disclosure	4,700,000
Unconsolidated joint venture investments, losses	600,000
Level 1 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Impairment Charges measured at Fair Value on a non-recurring basis
Long-lived assets - held and used and held for sale
Unconsolidated joint venture investments, fair value disclosure
Level 2 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Impairment Charges measured at Fair Value on a non-recurring basis
Long-lived assets - held and used and held for sale
Unconsolidated joint venture investments, fair value disclosure
Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Impairment Charges measured at Fair Value on a non-recurring basis
Long-lived assets - held and used and held for sale	28,700,000
Unconsolidated joint venture investments, fair value disclosure	$ 4,700,000