Commitments and Contingencies Commitments and Contingencies (Details) $ in Millions	Sep. 30, 2015 USD ($)
Commitments and Contingencies [Abstract]
Letters of credit and completion bonds	$ 150.8
Performance bonds outstanding	101.2
Performance letters of credit outstanding	25.3
Financial letters of credit	12.4
Financial letters of credit representing deposits on land and lot purchase agreements	6.5
Financial Bonds	11.9
Unrecorded conditional purchase obligation	$ 495.2