Variable Interest Entities (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2016 USD ($)
Variable Interest Entity [Line Items]
Equity Method Investment Board Seats	3
Variable Interest Entity, Consolidated, Assets, Not Pledged	$ 76.3	$ 56.1
Inventories [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Assets, Not Pledged	66.6	47.8
Cash [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Assets, Not Pledged	$ 0.7	$ 0.9
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Equity Method Investment Board Seats	2
Number of Individuals Required to Give Approval of an Action to the Board of Managers	1
Dallas and Atlanta Based Controlled Builders [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Percentage of Voting Interest	50.00%