Commitments and Contingencies Legal (Details) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Jun. 30, 2017	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Legal Liabilities Disclosure [Abstract]
Product Liability Accrual, Period Expense							$ 500
Standard and Extended Product Warranty Accrual, Period Increase (Decrease)	$ 8,500	$ 14,500	$ 2,800	$ 2,200	$ 8,500	$ 19,409	$ 0
Estimated Repair Costs for Affected Homes					9,100
Amount Reserved for Legal Expenses					$ 400	$ 300