Impairment Charges (Details 1) (USD $)	9 Months Ended
	Sep. 30, 2011
Impairment charges measured on a fair value on a non - recurring basis
Long lived assets held and used and held for sale fair value disclosure	$ 116,700,000
Unconsolidated joint venture investments Fair Value Disclosure	0
Unconsolidated joint venture investments, losses	1,671,000
Level 1 [Member]
Impairment charges measured on a fair value on a non - recurring basis
Long lived assets held and used and held for sale fair value disclosure	0
Unconsolidated joint venture investments Fair Value Disclosure	0
Level 2 [Member]
Impairment charges measured on a fair value on a non - recurring basis
Long lived assets held and used and held for sale fair value disclosure	0
Unconsolidated joint venture investments Fair Value Disclosure	0
Level 3 [Member]
Impairment charges measured on a fair value on a non - recurring basis
Long lived assets held and used and held for sale fair value disclosure	116,700,000
Unconsolidated joint venture investments Fair Value Disclosure	0
Fair Value, Measurements, Nonrecurring [Member]
Impairment charges measured on a fair value on a non - recurring basis
Fair value of assets measured on non recurring basis Losses	79,800,000
Unconsolidated joint venture investments, losses	$ 1,600,000