Commitments and Contingencies Commitments and Contingencies (Details) $ in Millions	Jun. 30, 2019 USD ($)
Commitments and Contingencies [Abstract]
Letters of credit and completion bonds	$ 233.5
Performance bonds outstanding	167.7
Performance letters of credit outstanding	48.8
Financial letters of credit	10.0
Financial letters of credit representing deposits on land and lot purchase agreements	9.6
Financial Bonds	7.0
Unrecorded conditional purchase obligation	$ 574.1