Commitments and contingencies.

No definition available.

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- Definition

The portion of the total reserve for legal claims that relates to the entity's construction defect matters, expressed as a percentage.

+ References

No definition available.

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- Definition

A deposit made by a purchaser of real estate to evidence good faith. It is customary for a buyer to give the seller earnest money at the time a sales contract is signed. The earnest money generally is credited to the down payment at closing, which is applied at closing as a component of payment against the purchase price.

+ References

No definition available.

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- Definition

The increase (decrease) during the reporting period in the amount of deposits given by the reporting entity to a seller which shows that the prospective buyer is serious about purchasing a property.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

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- Definition

Amount of increase (decrease) of consideration paid in advance for other costs that provide economic benefits in future periods.

+ References

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- Definition

Amount due in settlement of a claim for reimbursement from an insurance company when the Company has suffered a loss covered under an insurance policy.

+ References

No definition available.

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- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

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- Definition

Amount of litigation expense, including but not limited to legal, forensic, accounting, and investigative fees.

+ References

No definition available.

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- Definition

Amount of loss contingency liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349

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- Definition

Minimum amount of purchase arrangement in which the entity has agreed to expend funds to procure goods or services from a supplier.

+ References

No definition available.

+ Details

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- Definition

The noncurrent portion of the carrying value as of the balance sheet date of a type of municipal bond typically used to fund a development project. Also called special assessment limited liability bond, special district bond, special purpose bond, special tax bond and community development obligation. Interest owed to lenders is paid by taxes levied on the community benefiting from the particular bond-funded project. For example, if a bond of this sort was issued to pay for sidewalks to be repaved in a certain community, an additional tax would be levied on homeowners in the area benefiting from this project.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16)(a)(2))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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Commitments and Contingencies - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Sep. 30, 2018	Sep. 30, 2017
Commitments and Contingencies [Abstract]
Liabilities for various claims, complaints and other legal actions	$ 419.1	$ 443.6	$ 419.1	$ 443.6	$ 408.1	$ 420.6
Construction defect portion of loss contingency accrual, percentage	99.00%		99.00%		99.00%
Expenses related to legal claims			$ 14.6	39.0
Estimated insurance recoveries related to legal claims	$ 56.9	69.0	56.9	69.0	$ 54.6
Surety bonds	1,600.0		1,600.0
Outstanding letters of credit	148.3		148.3
Standby Letters of Credit [Member]
Commitments and Contingencies [Abstract]
Outstanding letters of credit	16.5		16.5
Forestar Consolidated [Member]
Commitments and Contingencies [Abstract]
Earnest money deposits	76.5		76.5
Remaining purchase price of land under option contracts	895.8		895.8
Forestar Consolidated [Member] \| Option Contracts Subject to Specific Performance Clauses [Member]
Commitments and Contingencies [Abstract]
Remaining purchase price of land under option contracts	50.9		50.9
Homebuilding [Member]
Commitments and Contingencies [Abstract]
Earnest money deposits	461.0		461.0
Remaining purchase price of land under option contracts	7,400.0		7,400.0
Homebuilding [Member] \| Line of Credit [Member]
Commitments and Contingencies [Abstract]
Outstanding letters of credit	128.0		128.0
Homebuilding [Member] \| Standby Letters of Credit [Member]
Commitments and Contingencies [Abstract]
Outstanding letters of credit	1.5		1.5
Homebuilding [Member] \| Option Contracts Subject to Specific Performance Clauses [Member]
Commitments and Contingencies [Abstract]
Remaining purchase price of land under option contracts	96.8		96.8
Homebuilding [Member] \| Cash [Member]
Commitments and Contingencies [Abstract]
Earnest money deposits	457.9		457.9
Homebuilding [Member] \| Notes Payable, Other Payables [Member]
Commitments and Contingencies [Abstract]
Earnest money deposits	3.1		3.1
Forestar Group [Member]
Commitments and Contingencies [Abstract]
Increase (Decrease) in Earnest Money Deposits Outstanding	4.7	11.8	16.8	14.0
Increase (Decrease) in Prepaid Expenses, Other	0.7	$ 5.9	3.7	$ 8.2
Forestar Group [Member] \| Line of Credit [Member]
Commitments and Contingencies [Abstract]
Outstanding letters of credit	3.8		3.8
Forestar Group [Member] \| Standby Letters of Credit [Member]
Commitments and Contingencies [Abstract]
Outstanding letters of credit	$ 15.0		$ 15.0