Notes Receivable From Real Estate Joint Ventures And Partnerships (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010	Sep. 30, 2011 Secured By Partnership Interest [Member]	Sep. 30, 2011 Secured By Property [Member]
Interest rate on notes receivable - range minimum			2.80%
Interest rate on notes receivable - range maximum			10.00%
Notes receivable due at various dates through			2013
Interest income on notes receivable	$ 900,000	$ 900,000	$ 1,700,000	$ 2,400,000
Allowance for uncollectible notes receivable	0		0		0
Extinguishment of notes receivable			21,900,000
Notes receivable from real estate joint ventures and partnerships	$ 159,760,000		$ 159,760,000		$ 184,788,000	$ 17,600,000	$ 43,000,000