Commitments and Contingencies Legal Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Liabilities Disclosure [Abstract]
Product Liability Accrual, Component Amount		$ 19.4	$ 0.5
Estimated Repair Costs for Affected Homes	$ 8.8
Amount Reserved for Legal Expenses	$ 0.3	$ 0.3

Recorded amount of the accrual for a material component of a product liability contingency.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 5.Y.Q2)
-URI http://asc.fasb.org/extlink&oid=27011672&loc=d3e149879-122751

Name:	us-gaap_ProductLiabilityAccrualComponentAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant