Subsequent Event (Details) $ in Millions	3 Months Ended
Mar. 31, 2018 USD ($)
Subsequent Event [Member] \| Forestar Group [Member]
Subsequent Event [Line Items]
Proceeds from Sale of Other Productive Assets	$ 232

Amount of cash inflow from the sale of tangible or intangible assets used to produce goods or deliver services, classified as other.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3179-108585

Name:	us-gaap_ProceedsFromSaleOfOtherProductiveAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration