Quarterly Results of Operations (Unaudited) (Details Textuals) (USD $) In Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2009	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009
Quarterly Results of Operations (Unaudited) (Textuals) [Abstract]
Inventory impairments and land option cost write-offs	$ 12.8	$ 9.9	$ 14.3	$ 8.4	$ 30.8	$ 30.3	$ 2.4	$ 1.2	$ 45.4	$ 64.7	$ 407.7