Forestar (FOR) 10-Q 30 Apr 19 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Mar. 31, 2019	Apr. 26, 2019
Document Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Trading Symbol	FOR
Entity Registrant Name	FORESTAR GROUP INC.
Entity Central Index Key	0001406587
Current Fiscal Year End Date	--09-30
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		41,959,866

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Mar. 31, 2019	Sep. 30, 2018
ASSETS
Cash and cash equivalents	$ 66.4	$ 318.8
Restricted cash	15.7	16.2
Total cash, cash equivalents and restricted cash	82.1	335
Real estate	851.5	498
Investment in unconsolidated ventures	7.4	11.7
Income taxes receivable	2.5	4.4
Property and equipment, net	2.4	1.7
Deferred tax asset, net	22.9	26.9
Other assets	16.1	15.4
TOTAL ASSETS	984.9	893.1
LIABILITIES
Accounts payable	14.5	7.9
Earnest money deposits on sales contracts	78.9	49.4
Accrued expenses and other liabilities	54.5	49.6
Debt, net	149.2	111.7
TOTAL LIABILITIES	297.1	218.6
COMMITMENTS AND CONTINGENCIES (Note 12)
Forestar Group Inc. shareholders’ equity:
Common stock, par value $1.00 per share, 200,000,000 authorized shares, 41,959,866 issued at March 31, 2019 and 41,939,403 issued at September 30, 2018	42	41.9
Additional paid-in capital	506.4	506.3
Retained earnings	138.5	125.1
Total Forestar Group Inc. shareholders’ equity	686.9	673.3
Noncontrolling interests	0.9	1.2
TOTAL EQUITY	687.8	674.5
TOTAL LIABILITIES AND EQUITY	$ 984.9	$ 893.1

Consolidated Balance Sheets (_2

Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Mar. 31, 2019	Sep. 30, 2018
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	41,959,866	41,939,403

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Revenues	$ 65.3	$ 22.6	$ 103.8	$ 53.5
Cost of sales	43.6	16.2	74.3	38.9
Selling, general and administrative expense	6.2	5.4	11.9	29.6
Equity in earnings of unconsolidated ventures	0	(1.5)	(0.6)	(8.5)
Gain on sale of assets	0	(2.7)	(0.9)	(2.7)
Interest expense	0	2.1	0	4.2
Interest and other income	(0.9)	(1.6)	(2.2)	(2.3)
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE TAXES	16.4	4.7	21.3	(5.7)
Income tax expense	3.6	0.1	4.6	12.6
NET INCOME (LOSS) FROM CONTINUING OPERATIONS	12.8	4.6	16.7	(18.3)
INCOME FROM DISCONTINUED OPERATIONS, NET OF TAXES	0	0	0	7.2
CONSOLIDATED NET INCOME (LOSS)	12.8	4.6	16.7	(11.1)
Less: Net income attributable to noncontrolling interests	2.7	0.1	3.3	2
NET INCOME (LOSS) ATTRIBUTABLE TO FORESTAR GROUP INC.	$ 10.1	$ 4.5	$ 13.4	$ (13.1)
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING
Basic (in shares)	41,959,866	41,938,936	41,956,179	41,948,180
Diluted (in shares)	41,966,099	41,966,366	41,962,399	41,961,895
NET INCOME (LOSS) PER BASIC SHARE
Continuing operations, basic (usd per share)	$ 0.24	$ 0.11	$ 0.32	$ (0.48)
Discontinued operations, basic (usd per share)	0	0	0	0.17
NET INCOME (LOSS) PER BASIC SHARE (usd per share)	0.24	0.11	0.32	(0.31)
NET INCOME (LOSS) PER DILUTED SHARE
Continuing operations, diluted (usd per share)	0.24	0.11	0.32	(0.48)
Discontinued operation, diluted (usd per share)	0	0	0	0.17
NET INCOME (LOSS) PER DILUTED SHARE (usd per share)	$ 0.24	$ 0.11	$ 0.32	$ (0.31)

Consolidated Statements of Tota

Consolidated Statements of Total Equity (Unaudited) Statement - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Noncontrolling Interest [Member]
Beginning balances (shares) at Sep. 30, 2017		44,803,603
Retirement of treasury shares (shares)		(2,864,667)
Ending balances (shares) at Dec. 31, 2017		41,938,936
Beginning balances at Sep. 30, 2017	$ 631.3	$ 44.8	$ 549.4	$ 80.4	$ (44.5)	$ 1.2
Net income (loss)	(15.6)	0	0	(17.6)	0	2
Settlement of equity awards	(12.8)	0	(12.8)	0	0	0
Retirement of treasury shares	0	(2.9)	(35.1)	(6.5)	44.5	0
Stock-based compensation expense	4.5	0	4.5	0	0	0
Distributions to noncontrolling interests	(1.8)	0	0	0	0	(1.8)
Ending balances at Dec. 31, 2017	605.6	$ 41.9	506	56.3	0	1.4
Beginning balances (shares) at Sep. 30, 2017		44,803,603
Ending balances (shares) at Mar. 31, 2018		41,938,936
Beginning balances at Sep. 30, 2017	631.3	$ 44.8	549.4	80.4	(44.5)	1.2
Net income (loss)	(11.1)
Ending balances at Mar. 31, 2018	610	$ 41.9	506.1	60.8	0	1.2
Beginning balances (shares) at Dec. 31, 2017		41,938,936
Ending balances (shares) at Mar. 31, 2018		41,938,936
Beginning balances at Dec. 31, 2017	605.6	$ 41.9	506	56.3	0	1.4
Net income (loss)	4.6	0	0	4.5	0	0.1
Stock-based compensation expense	0.1	0	0.1	0	0	0
Distributions to noncontrolling interests	(0.3)	0	0	0	0	(0.3)
Ending balances at Mar. 31, 2018	610	$ 41.9	506.1	60.8	0	1.2
Beginning balances (shares) at Sep. 30, 2018		41,939,403
Stock issued under employee incentive plans (shares)		20,463
Ending balances (shares) at Dec. 31, 2018		41,959,866
Beginning balances at Sep. 30, 2018	674.5	$ 41.9	506.3	125.1	0	1.2
Net income (loss)	3.9	0	0	3.3	0	0.6
Stock issued under employee incentive plans	0	0.1	(0.1)	0	0	0
Stock-based compensation expense	0.1	0	0.1	0	0	0
Distributions to noncontrolling interests	(0.5)	0	0	0	0	(0.5)
Ending balances at Dec. 31, 2018	678	$ 42	506.3	128.4	0	1.3
Beginning balances (shares) at Sep. 30, 2018		41,939,403
Ending balances (shares) at Mar. 31, 2019		41,959,866
Beginning balances at Sep. 30, 2018	674.5	$ 41.9	506.3	125.1	0	1.2
Net income (loss)	16.7
Ending balances at Mar. 31, 2019	687.8	$ 42	506.4	138.5	0	0.9
Beginning balances (shares) at Dec. 31, 2018		41,959,866
Ending balances (shares) at Mar. 31, 2019		41,959,866
Beginning balances at Dec. 31, 2018	678	$ 42	506.3	128.4	0	1.3
Net income (loss)	12.8	0	0	10.1	0	2.7
Stock-based compensation expense	0.1	0	0.1	0	0	0
Distributions to noncontrolling interests	(3.1)	0	0	0	0	(3.1)
Ending balances at Mar. 31, 2019	$ 687.8	$ 42	$ 506.4	$ 138.5	$ 0	$ 0.9

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Consolidated net income (loss)	$ 16.7	$ (11.1)
Adjustments:
Depreciation and amortization	3	2.5
Deferred income taxes	3.9	(1.1)
Equity in earnings of unconsolidated ventures	(0.6)	(8.5)
Distributions of earnings of unconsolidated ventures	4.9	8.3
Share-based compensation	0.2	4.2
Asset impairments	0.4	9.3
Loss on debt extinguishment, net	0	0.6
Gain on sale of assets	(0.9)	(2.7)
Changes in operating assets and liabilities:
Increase in real estate	(353.5)	(173.5)
Increase in other assets	(1.6)	(3.1)
Increase in accounts payable and other accrued liabilities	12.6	1.6
Increase in earnest money deposits on sales contracts	29.5	19.1
Decrease in income taxes receivable	1.9	16.6
Net cash used in operating activities	(283.5)	(137.8)
CASH FLOWS FROM INVESTING ACTIVITIES:
Property, equipment, software and other	(0.8)	0
Investment in unconsolidated ventures	0	(0.1)
Return of investment in unconsolidated ventures	0.1	7.1
Proceeds from sale of assets	0	228.6
Net cash (used in) provided by investing activities	(0.7)	235.6
CASH FLOWS FROM FINANCING ACTIVITIES:
Payments of debt	(5)	(10.1)
Additions to debt	40	1.5
Deferred financing fees	0	(0.2)
Distributions to noncontrolling interests, net	(3.6)	(2)
Settlement of equity awards	(0.1)	(12.8)
Net cash provided by (used in) financing activities	31.3	(23.6)
Net (decrease) increase in cash, cash equivalents and restricted cash	(252.9)	74.2
Cash, cash equivalents and restricted cash at beginning of period	335	402.2
Cash, cash equivalents and restricted cash at end of period	$ 82.1	$ 476.4

Basis of Presentation

Basis of Presentation	6 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited, consolidated financial statements include the accounts of Forestar Group Inc. (Forestar) and all of its 100% owned, majority-owned and controlled subsidiaries, which are collectively referred to as the "Company", "we", or "our", unless the context otherwise requires. The Company accounts for its investment in other entities in which it has significant influence over operations and financial policies using the equity method. The Company eliminates all material intercompany accounts and transactions. Noncontrolling interests in consolidated pass-through entities are recognized before income taxes. The financial statements have been prepared in accordance with U.S. Generally Accepted Accounting Principles (GAAP) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. In the opinion of management, these financial statements reflect all adjustments considered necessary to fairly state the results for the interim periods shown, including normal recurring accruals and other items. These financial statements, including the consolidated balance sheet as of September 30, 2018 , which was derived from audited financial statements, do not include all of the information and notes required by GAAP for complete financial statements and should be read in conjunction with the consolidated financial statements and accompanying notes included in the Company’s annual report on Form 10-KT for the nine months ended September 30, 2018 . The Company divested substantially all of its oil and gas working interest properties in 2016, and completed the sale of all oil and gas assets and related entities in 2017. As a result of selling the entities in 2017, the Company recognized a tax benefit during the six months ended March 31, 2018 that has been recorded as income from discontinued operations. There was no activity related to these discontinued operations during the three and six months ended March 31, 2019 . The transactions included in net income in the consolidated statements of operations are the same as those that would be presented in comprehensive income. Thus, the Company's net income equates to comprehensive income. On October 5, 2017, Forestar became a majority-owned subsidiary of D.R. Horton, Inc. (D.R. Horton) by virtue of a merger with a wholly-owned subsidiary of D.R. Horton (the Merger). Immediately following the Merger, D.R. Horton owned 75% of the Company's outstanding common stock. In connection with the Merger, the Company entered into certain agreements with D.R. Horton including a Stockholder’s Agreement, a Master Supply Agreement, and a Shared Services Agreement. D.R. Horton is considered a related party of Forestar under GAAP. Changes in Presentation and Reclassifications Certain items have been reclassified in the prior year financial statements to conform to the presentation and classifications used in the current year. Receivables, prepaid expenses, land purchase contract deposits, and intangible assets have been reclassified to other assets in the prior year consolidated balance sheet. Accrued employee compensation and benefits, accrued property taxes, accrued interest, other accrued expenses and other liabilities have been reclassified to accrued expenses and other liabilities in the prior year consolidated balance sheet. Other operating expense and general and administrative expense have been combined into one line item which is titled selling, general and administrative expense in the prior year consolidated statement of operations. In addition, certain items have been reclassified from selling, general and administrative expenses to cost of sales in the prior year statement of operations to conform to classifications used in the current year. The Company has reclassified the change in earnest money deposits in the prior year statement of cash flows from change in accounts payable and other accrued liabilities to conform to the classifications used in the current year. The Company has reclassified real estate cost of sales, real estate development and acquisition expenditures, reimbursements from utility and improvement districts, and other to change in real estate in the prior year statement of cash flows to conform to classifications used in the current year. The Company has reclassified proceeds from land and lot closings held for the Company’s benefit at title companies in the prior year consolidated balance sheet from receivables to cash and cash equivalents to conform to the classification used in the current year. These reclassifications had no effect on the Company's consolidated operating results, balance sheet or cash flows. In connection with the adoption of Accounting Standards Update (ASU) 2016-18 on October 1, 2018, restricted cash is included with cash and cash equivalents when reconciling beginning and ending cash amounts in the consolidated statements of cash flows. Prior period amounts have been reclassified to conform to the current year presentation, resulting in a decrease in cash used in financing activities of $39.7 million for the six months ended March 31, 2018 . Adoption of New Accounting Standards On October 1, 2018, the Company adopted Accounting Standards Codification 606, "Revenue from Contracts with Customers" (ASC 606), which is a comprehensive new revenue recognition model that requires revenue to be recognized in a manner to depict the transfer of goods or services and satisfaction of performance obligations to a customer at an amount that reflects the consideration expected to be received in exchange for those goods or services. The Company applied the modified retrospective method to contracts that were not completed as of October 1, 2018. Results for the reporting period beginning on October 1, 2018 are presented under ASC 606, while prior period amounts were not adjusted and will continue to be reported under the previous accounting standards. Under ASC 606, the Company's performance obligations are typically satisfied at closing. However, there may be instances in which the Company has an unsatisfied remaining performance obligation at the time of closing. In these instances, the Company records contract liabilities and recognizes those revenues over time using the percentage of completion method based upon actual costs incurred. Generally, the Company's unsatisfied remaining performance obligations are expected to have an original duration of less than one year. As of October 1, 2018, the Company established contract liabilities of $6.4 million related to its remaining unsatisfied performance obligations at the time of adoption of ASC 606. There was no impact to the amount or timing of revenues recognized as a result of applying ASC 606 for the three and six months ended March 31, 2019 , and there have not been significant changes to the Company’s business processes, systems, or internal controls as a result of implementing the standard. A summary of items impacted as the result of adopting ASC 606 follows: As of March 31, 2019 As Reported Impact of Adoption As Adjusted (In millions) Real estate $ 851.5 $ 7.0 $ 844.5 Contract liabilities 7.9 7.9 — Deferred income 10.8 (0.9 ) 11.7 In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230), to address eight specific cash flow issues with the objective of reducing the existing diversity in practice. The updated standard is effective for financial statements issued for annual periods beginning after December 15, 2017 and interim periods within those fiscal years. The Company adopted the guidance as of October 1, 2018 and did not have a material impact on its consolidated statements of cash flows. In November 2016, the FASB issued ASU 2016-18, “Statement of Cash Flows - Restricted Cash,” which requires amounts generally described as restricted cash and restricted cash equivalents be included with cash and cash equivalents when reconciling the total beginning and ending amounts for the periods shown on the statement of cash flows. The Company adopted the guidance as of October 1, 2018 on a retrospective basis and made the required changes to its statements of cash flows as described in the “Changes in Presentation and Reclassifications” section above. In May 2017, the FASB issued ASU 2017-09, “Compensation - Stock Compensation: Scope of Modification Accounting,” which clarifies which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting. Under the new guidance, modification accounting is required if the fair value, vesting conditions or classification (equity or liability) of the new award are different from the original award immediately before the original award is modified. The Company adopted the guidance as of October 1, 2018 and did not have a material impact on its consolidated financial position, results of operations or cash flows. Recent Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). This ASU requires lessees to put most leases on their balance sheets but recognize expenses on their income statements in a manner that is similar to today's accounting. This guidance also eliminates today's real estate-specific provisions for all entities. For lessors, the guidance modifies the classification criteria and the accounting for sales-type and direct financing leases. This guidance is effective for the Company on October 1, 2019 and early adoption is permitted. The new standard requires a modified retrospective transition approach for all leases existing at, or entered into after, the date of initial application, with an option to use certain transition relief. The Company is currently evaluating the effect the updated standard will have on our financial position, results of operations and cash flows.

Segment Information

Segment Information	6 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
Segment Information	Segment Information Historically, the Company managed its operations through its real estate segment, mineral resources segment (previously referred to as oil and gas) and other segment (previously referred to as other natural resources). During the three months ended December 31, 2018 , the Company began managing its operations through one real estate segment. As such, the operating results of the Company's real estate segment are consistent with its consolidated operating results and no separate disclosure is required as of and for the three and six months ended March 31, 2019 . The Company's real estate segment is its core business and is expected to generate all of the Company’s revenues in fiscal 2019. The real estate segment primarily acquires land and develops infrastructure for single-family residential communities. The Company's real estate segment generates its revenues principally from sales of residential single-family finished lots to local, regional and national homebuilders. The Company has other business activities which were presented in its other segment in prior periods. The assets and results of operations of these business activities are immaterial and are included within the Company's real estate segment in the current periods. Additionally, as of and for the three and six months ended March 31, 2019 , all assets and results of operations have been included in the real estate segment. In prior periods, certain costs and assets were not allocated to the Company’s segments. During the three months ended December 31, 2018 , the Company began evaluating the results of operations of its real estate segment based on income from continuing operations before income taxes. As a result, all of the Company’s results of operations have been allocated to the real estate segment for the three and six months ended March 31, 2019 . This change in the measure of segment profit (loss) was adopted prospectively and the prior period segment results have not been adjusted to conform to the current period. In prior periods, segment earnings (loss) consist of operating income, equity in earnings (loss) of unconsolidated ventures, gain on sales of assets, interest income and net income (loss) attributable to noncontrolling interests. Items not allocated to segments in prior periods consist of general and administrative expense, share-based and long-term incentive compensation, gain on sale of timberland assets, interest expense, and other corporate interest and other income. The accounting policies of the reporting segment is described throughout Note 1 in the Company's annual report on Form 10-KT for the nine months ended September 30, 2018 . Total assets by segment at September 30, 2018 are as follows: September 30, 2018 Real Estate Other Items Not Allocated Consolidated (In millions) Cash and cash equivalents $ — $ — $ 318.8 $ 318.8 Restricted cash — — 16.2 16.2 Real estate 498.0 — — 498.0 Investment in unconsolidated ventures 11.7 — — 11.7 Income taxes receivable — — 4.4 4.4 Property and equipment, net — 1.5 0.2 1.7 Deferred tax asset, net — — 26.9 26.9 Other assets 12.4 0.4 2.6 15.4 $ 522.1 $ 1.9 $ 369.1 $ 893.1 Segment results for the three and six months ended March 31, 2018 are as follows: Three Months Ended March 31, 2018 Real Estate Other Items Not Allocated Consolidated (In millions) Revenues $ 22.6 $ — $ — $ 22.6 Cost of sales 15.6 0.6 — 16.2 Selling, general and administrative expense 1.6 — 3.8 5.4 Equity in earnings of unconsolidated ventures (1.5 ) — — (1.5 ) Gain on sale of assets (2.7 ) — — (2.7 ) Interest expense — — 2.1 2.1 Interest and other income (0.2 ) — (1.4 ) (1.6 ) Income (loss) from continuing operations before taxes $ 9.8 $ (0.6 ) $ (4.5 ) $ 4.7 Net income attributable to noncontrolling interests 0.1 — — 0.1 Income (loss) from continuing operations before taxes attributable to Forestar Group Inc. $ 9.7 $ (0.6 ) $ (4.5 ) $ 4.6 Six Months Ended March 31, 2018 Real Estate Other Items Not Allocated Consolidated (In millions) Revenues $ 53.5 $ — $ — $ 53.5 Cost of sales 32.4 6.5 — 38.9 Selling, general and administrative expense 7.5 0.1 22.0 29.6 Equity in earnings of unconsolidated ventures (8.5 ) — — (8.5 ) Gain on sale of assets (2.7 ) — — (2.7 ) Interest expense — — 4.2 4.2 Interest and other income (0.9 ) — (1.4 ) (2.3 ) Income (loss) from continuing operations before taxes $ 25.7 $ (6.6 ) $ (24.8 ) $ (5.7 ) Net income attributable to noncontrolling interests 2.0 — — 2.0 Income (loss) from continuing operations before taxes attributable to Forestar Group Inc. $ 23.7 $ (6.6 ) $ (24.8 ) $ (7.7 )

Real Estate

Real Estate	6 Months Ended
	Mar. 31, 2019
Real Estate [Abstract]
Real Estate	Real Estate Real estate consists of: March 31, September 30, (In millions) Developed and under development projects $ 803.0 $ 463.1 Land held for development 48.5 34.9 $ 851.5 $ 498.0 In the six months ended March 31, 2019 , the Company invested $300.2 million for the acquisition of residential real estate and $119.1 million for the development of residential real estate. At March 31, 2019 and September 30, 2018 , land held for development primarily consists of undeveloped land which the Company has the contractual right to sell to D.R. Horton within approximately one year of its purchase or, if D.R. Horton elects, at an earlier date, at a sales price equal to the carrying value of the land at the time of sale plus additional consideration which ranges from 12% to 16% per annum. Alternatively, at any time prior to its sale of the undeveloped land to D.R. Horton, the Company and D.R. Horton may elect to have Forestar develop the land into residential lots and enter into a finished lot purchase and sale agreement with D.R. Horton.

Revenues Revenues (Notes)

Revenues Revenues (Notes)	6 Months Ended
	Mar. 31, 2019
Revenues [Abstract]
Revenue from Contract with Customer [Text Block]	Revenues On October 1, 2018, the Company adopted Accounting Standards Codification 606, "Revenue from Contracts with Customers" (ASC 606), which is a comprehensive new revenue recognition model that requires revenue to be recognized in a manner to depict the transfer of goods or services and satisfaction of performance obligations to a customer at an amount that reflects the consideration expected to be received in exchange for those goods or services. The Company applied the modified retrospective method to contracts that were not completed as of October 1, 2018. Results for the reporting period beginning on October 1, 2018 are presented under ASC 606, while prior period amounts were not adjusted and will continue to be reported under the previous accounting standards. Under ASC 606 the Company's performance obligations are typically satisfied at closing. However, there may be instances in which the Company has an unsatisfied remaining performance obligation at the time of closing. In these instances, the Company records contract liabilities and recognizes those revenues over time using the percentage of completion method based upon actual costs incurred. Generally, the Company's unsatisfied remaining performance obligations are expected to have an original duration of less than one year. As of October 1, 2018, the Company established contract liabilities of $6.4 million related to its remaining unsatisfied performance obligations at the time of adoption of ASC 606. There was no impact to the amount or timing of revenues recognized as a result of applying ASC 606 for the three and six months ended March 31, 2019 Revenues consist of: Three Months Ended March 31, Six Months Ended March 31, 2019 2018 2019 2018 (In millions) Residential lot sales $ 49.3 $ 20.4 $ 84.0 $ 41.5 Residential tract sales — — — 2.3 Commercial tract sales 15.0 2.0 18.5 9.2 Other 1.0 0.2 1.3 0.5 $ 65.3 $ 22.6 $ 103.8 $ 53.5 In the three and six months ended March 31, 2019 the Company recognized $2.1 million and $3.0 million of residential lot sales revenue as a result of its progress towards completion of its remaining unsatisfied performance obligations.

Investment in Unconsolidated Ve

Investment in Unconsolidated Ventures	6 Months Ended
	Mar. 31, 2019
Equity Method Investments and Joint Ventures [Abstract]
Investment in Unconsolidated Ventures	Investment in Unconsolidated Ventures In the past, the Company participated in real estate ventures for the purpose of acquiring and developing residential, multifamily and mixed-use communities in which the Company may or may not have a controlling financial interest. GAAP requires consolidation of Variable Interest Entities (VIEs) in which an enterprise has a controlling financial interest and is the primary beneficiary. A controlling financial interest will have both of the following characteristics: (a) the power to direct the VIE activities that most significantly impact economic performance and (b) the obligation to absorb the VIE losses and right to receive benefits that are significant to the VIE. The Company examines specific criteria and uses judgment when determining whether a venture is a VIE and whether the Company is the primary beneficiary. The Company performs this review initially at the time it enters into venture agreements and reassesses upon reconsideration events. At March 31, 2019 , the Company had ownership interests in four ventures that it accounted for using the equity method, none of which was a VIE. Combined summarized balance sheet information for our ventures accounted for using the equity method follows: March 31, September 30, (In millions) Assets: Cash and cash equivalents $ 1.7 $ 10.2 Real estate 13.7 17.2 Other assets 0.1 0.1 Total assets $ 15.5 $ 27.5 Liabilities and Equity: Accounts payable and other liabilities $ 0.3 $ 0.6 Equity 15.2 26.9 Total liabilities and equity $ 15.5 $ 27.5 Forestar's investment in unconsolidated ventures $ 7.4 $ 11.7 Combined summarized income statement information for our ventures accounted for using the equity method follows: Three Months Ended March 31, Six Months Ended March 31, 2019 2018 2019 2018 (In millions) Revenues $ — $ 3.4 $ 1.8 $ 12.0 Earnings — 4.3 1.4 21.7 Forestar's equity in earnings of unconsolidated ventures — 1.5 0.6 8.5 In the six months ended March 31, 2018 , a venture in which the Company owned a 30% interest sold a multifamily project in Nashville for $71.7 million and recognized a gain of $19.0 million . The Company's share of earnings from this transaction was $7.8 million .

Discontinued Operations

Discontinued Operations	6 Months Ended
	Mar. 31, 2019
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	Discontinued Operations The Company divested substantially all of its oil and gas working interest properties in 2016 and completed the sale of all oil and gas assets and related entities in 2017. As a result of selling the entities in 2017, the Company recognized a tax benefit of $7.2 million in the six months ended March 31, 2018 that has been recorded as income from discontinued operations. There was no activity related to these discontinued operations during the six months ended March 31, 2019 .

Other Assets, Accrued Expenses

Other Assets, Accrued Expenses and Other Liabilities	6 Months Ended
	Mar. 31, 2019
Other Assets, Accrued Expenses and Other Liabilities [Abstract]
Other Assets And Other Liabilities [Text Block]	The Company's other assets at March 31, 2019 and September 30, 2018 were as follows: March 31, September 30, (In millions) Receivables, net $ 1.4 $ 2.7 Prepaid expenses 3.3 3.1 Land purchase contract deposits 6.7 4.1 Intangible assets — 0.5 Other assets 4.7 5.0 $ 16.1 $ 15.4 The Company's accrued expenses and other liabilities at March 31, 2019 and September 30, 2018 were as follows: March 31, September 30, (In millions) Accrued employee compensation and benefits $ 5.8 $ 6.7 Accrued property taxes 0.4 1.7 Accrued interest 0.4 0.4 Contract liabilities 7.9 — Deferred income 10.8 11.6 Other accrued expenses 26.4 27.2 Other liabilities 2.8 2.0 $ 54.5 $ 49.6 Contract liabilities at March 31, 2019 represents the Company's unsatisfied remaining performance obligations in the development of 261 lots that have been sold to D.R. Horton which will be recognized over time on a percentage of completion basis.

Debt, net

Debt, net	6 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Debt, net	Debt, net Debt consists of: March 31, September 30, (In millions) 3.75% convertible senior notes due 2020, net of discount and fees $ 114.2 $ 111.7 Senior unsecured revolving credit facility, maturing 2021 35.0 — $ 149.2 $ 111.7 Senior Unsecured Revolving Credit Facility On August 16, 2018 , the Company entered into a $380.0 million senior unsecured revolving credit facility with an uncommitted $190.0 million accordion feature that could increase the size of the facility to $570.0 million , subject to certain conditions and availability of additional bank commitments. The facility also provides for the issuance of letters of credit with a sublimit equal to 50% of the revolving credit commitment. Borrowings under the revolving credit facility are subject to a borrowing base formula based on the book value of the Company's real estate and unrestricted cash. The maturity date of the facility is August 16, 2021 . The maturity date of the revolving credit facility may be extended by up to one year on up to three occasions, subject to approval of lenders holding a majority of the commitments. Letters of credit issued under the facility reduce the available borrowing capacity. At March 31, 2019 , there were $35.0 million in borrowings outstanding at a 4.8% annual interest rate and $3.8 million of letters of credit issued under the revolving credit facility. The revolving credit facility includes customary affirmative and negative covenants, events of default and financial covenants. The financial covenants require a minimum level of tangible net worth, a minimum level of liquidity, and a maximum allowable leverage ratio. These covenants are measured as defined in the credit agreement governing the facility and are reported to the lenders quarterly. A failure to comply with these financial covenants could allow the lending banks to terminate the availability of funds under the revolving credit facility or cause any outstanding borrowings to become due and payable prior to maturity. At March 31, 2019 , the Company was in compliance with all of the covenants, limitations and restrictions of its revolving credit facility. 3.75% Convertible Senior Notes due 2020 At March 31, 2019 , the principal amount of the 3.75% Convertible Senior Notes due 2020 ("Convertible Notes") was $118.9 million and the unamortized debt discount was $4.3 million . The effective interest rate on the liability component was 8.0% and the carrying amount of the equity component was $16.8 million . The Company intends to settle the principal amount of the Convertible Notes in cash upon conversion in 2020, with any excess conversion value to be settled in shares of its common stock. At March 31, 2019 and September 30, 2018 , the Company had $0.4 million and $0.7 million in unamortized deferred financing fees which were deducted from its debt.

Fair Value

Fair Value	6 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value	Fair Value Fair value is the exchange price that would be received for an asset or paid to transfer a liability in an orderly transaction between market participants. In arriving at a fair value measurement, the Company uses a fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable. The three levels of inputs used to establish fair value are the following: • Level 1 — Quoted prices in active markets for identical assets or liabilities; • Level 2 — Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; and • Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company elected not to use the fair value option for cash and cash equivalents, restricted cash and debt. For the financial assets and liabilities that the Company does not reflect at fair value, the following tables present both their respective carrying value and fair value at March 31, 2019 and September 30, 2018 . Fair Value at March 31, 2019 Carrying Value Level 1 Level 2 Level 3 Total (in millions) Cash and cash equivalents (a) $ 66.4 $ 66.4 $ — $ — $ 66.4 Restricted cash (a) 15.7 15.7 — — 15.7 Debt (b) (c) 149.6 — 115.1 35.0 150.1 Fair Value at September 30, 2018 Carrying Value Level 1 Level 2 Level 3 Total (in millions) Cash and cash equivalents (a) $ 318.8 $ 318.8 $ — $ — $ 318.8 Restricted cash (a) 16.2 16.2 — — 16.2 Debt (b) (c) 112.4 — 113.2 — 113.2 _____________________ (a) The fair values of cash, cash equivalents and restricted cash approximate their carrying values due to their short-term nature and are classified as Level 1 within the fair value hierarchy. (b) The fair value of the senior notes is determined based on quoted prices, which is classified as Level 2 within the fair value hierarchy. (c) The fair value of borrowings under the revolving credit facility approximate carrying value due to the floating interest rate terms and is classified as Level 3 within the fair value hierarchy. Non-financial assets measured at fair value on a non-recurring basis principally include real estate assets which are measured for impairment. Non-financial assets measured at fair value on a non-recurring basis are as follows: March 31, 2019 September 30, 2018 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total (In millions) Non-financial Assets: Real estate $ — $ — $ — $ — $ — $ 0.2 $ — $ 0.2 At September 30, 2018 , the Company based the valuations of its real estate primarily on offers received from third parties.

Net Income (Loss) per Share

Net Income (Loss) per Share	6 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Net Income (Loss) per Share	Net Income per Share The computations of basic and diluted earnings per share are as follows: Three Months Ended March 31, Six Months Ended March 31, 2019 2018 2019 2018 (In millions, except share data) Numerator: Continuing operations Net income (loss) from continuing operations $ 12.8 $ 4.6 $ 16.7 $ (18.3 ) Less: Net income attributable to noncontrolling interest 2.7 0.1 3.3 2.0 Net income (loss) from continuing operations attributable to Forestar Group Inc. $ 10.1 $ 4.5 $ 13.4 $ (20.3 ) Discontinued operations Net income from discontinued operations available for diluted earnings per share $ — $ — $ — $ 7.2 Denominator: Weighted average common shares outstanding — basic 41,959,866 41,938,936 41,956,179 41,948,180 Dilutive effect of share based compensation 6,233 27,430 6,220 13,715 Total weighted average shares outstanding — diluted 41,966,099 41,966,366 41,962,399 41,961,895 Anti-dilutive awards excluded from diluted weighted average shares — — — 15,434 The Company intends to settle the principal amount of the Convertible Notes in cash upon conversion with any excess conversion value to be settled in shares of its common stock. Therefore, only the amount in excess of the par value of the Convertible Notes will be included in the calculation of diluted net income per share using the treasury stock method. As such, the Convertible Notes have no impact on diluted net income per share until the price of the Company's common stock exceeds the conversion price of the Convertible Notes of $51.42 . The price of the Company's common stock did not exceed the conversion price so the Convertible Notes had no impact on diluted net income per share in any of the periods presented.

Income Taxes

Income Taxes	6 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company's effective tax rate from continuing operations was 22% for both the three and six months ended March 31, 2019 . The Company's effective tax rate from continuing operations was 1% for the three months ended March 31, 2018 , which included the impact of the Tax Cuts and Jobs Act (“Tax Act”) and a tax benefit from the release of a portion of its valuation allowance as the result of the realization of certain deferred tax assets. The Company’s effective tax rate from continuing operations was 221% for the six months ended March 31, 2018 which included nondeductible transactions costs related to the Merger, the impairment of nondeductible goodwill related to the Company's oil and gas operations, other adjustments to the Company's valuation allowance as a result of the generation and utilization of its deferred tax assets, and the impact of the Tax Act. The Company’s effective tax rate for both periods includes the effect of state income taxes, nondeductible items and benefits for noncontrolling interests. At March 31, 2019 and September 30, 2018 , deferred tax assets, net of deferred tax liabilities, were $26.2 million and $30.3 million , offset by a valuation allowance of $3.3 million and $3.4 million for the portion of the deferred tax assets that the Company has determined is more likely than not to be unrealizable. The valuation allowance was recorded because it is more likely than not that a portion of the Company's state deferred tax assets, primarily net operating loss (NOL) carryforwards, will not be realized because the Company is no longer operating in some states or the NOL carryforward periods are too brief to realize the related deferred tax asset. The Company will continue to evaluate both the positive and negative evidence in determining the need for a valuation allowance on its deferred tax assets. Any reversal of the valuation allowance in future periods will impact the effective tax rate. On October 5, 2017 , D.R. Horton Inc. acquired 75% of the Company’s common stock resulting in an ownership change under Section 382 of the Internal Revenue Code. Section 382 limits the Company’s ability to use certain tax attributes and built-in losses and deductions in a given year. The Company’s tax attributes or built-in losses and deductions that were limited in 2017 or 2018 are expected to be fully utilized in future years with the exception of some state NOL carryforwards. The Company's unrecognized tax benefits totaled $1.1 million at March 31, 2019 , all of which would affect its effective tax rate, if recognized.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Contractual Obligations and Off-Balance Sheet Arrangements In support of our residential lot development business, we have a surety bond program that provides financial assurance to beneficiaries related to the execution and performance of certain development obligations. At March 31, 2019 , the Company had $95.6 million of surety bonds outstanding. Secured Letter of Credit Agreement The Company has a secured standby letter of credit facility (LC Facility) that requires it to deposit cash as collateral with the issuing bank. At March 31, 2019 , letters of credit outstanding under the LC Facility totaled $15.0 million , secured by $15.7 million in cash, which is classified as restricted cash on the Company's consolidated balance sheets. Litigation The Company is involved in various legal proceedings that arise from time to time in the ordinary course of business and believes that adequate reserves have been established for any probable losses. The Company does not believe that the outcome of any of these proceedings will have a significant adverse effect on its financial position, long-term results of operations or cash flows. It is possible, however, that charges related to these matters could be significant to the Company's results or cash flows in any one accounting period.

Related Party Transactions (Not

Related Party Transactions (Notes)	6 Months Ended
	Mar. 31, 2019
Related Party Transactions [Abstract]
Related Party Transactions Disclosure [Text Block]	Related Party Transactions On October 6, 2017 , the Company entered into a Shared Services Agreement with D.R. Horton whereby D.R. Horton provides the Company with certain administrative, compliance, operational and procurement services. During the six months ended March 31, 2019 and March 31, 2018 , the Company paid D.R. Horton $1.0 million and $0.3 million for these shared services and $0.6 million and $0.4 million for the cost of health insurance and other employee benefits. These expenses are included within selling, general and administrative expense in the consolidated statement of operations. Under the terms of the Master Supply Agreement with D.R. Horton, both companies identify land development opportunities to expand Forestar's portfolio of assets. At March 31, 2019 , the Company owned or controlled through option purchase contracts approximately 31,400 residential lots, of which nearly 12,100 are under contract to sell to D.R. Horton. Additionally, D.R. Horton has the right of first offer on nearly 9,600 of these residential lots based on executed purchase and sale agreements. At March 31, 2019 and September 30, 2018 , the Company had earnest money deposit liabilities of $76.2 million and $45.3 million related to earnest money deposits from land and lot option purchase contracts with D.R. Horton. In the three months ended March 31, 2019 , the Company sold 453 residential lots to D.R. Horton for $37.7 million . In the six months ended March 31, 2019 , the Company sold 908 residential lots to D.R. Horton for $70.2 million . In both the three and six months ended March 31, 2018 , the Company sold 183 residential lots to D.R. Horton for $8.5 million . At March 31, 2019 , the Company had contract liabilities of $7.9 million related to its unsatisfied remaining performance obligations in the development of 261 lots that have been sold to D.R. Horton which will be recognized over time on a percentage of completion basis. During the three and six months ended March 31, 2019 , the Company reimbursed D.R. Horton approximately $4.7 million and $16.8 million for previously paid earnest money and $0.7 million and $3.7 million for pre-acquisition and other due diligence and development costs related to land purchase contracts whereby D.R. Horton assigned its rights under these land purchase contracts to Forestar. During the three and six months ended March 31, 2018 , the Company reimbursed D.R. Horton approximately $11.8 million and $14.0 million for previously paid earnest money and $5.9 million and $8.2 million for pre-acquisition and other due diligence and development costs. At March 31, 2019 and September 30, 2018 , land held for development was $48.5 million and $ 34.9 million . Land held for development primarily consists of undeveloped land which the Company has the contractual right to sell to D.R. Horton within approximately one year of its purchase or, if D.R. Horton elects, at an earlier date, at a sales price equal to the carrying value of the land at the time of sale plus additional consideration which ranges from 12% to 16% per annum. Alternatively, at any time prior to its sale of the undeveloped land to D.R. Horton, the Company and D.R. Horton may elect to have Forestar develop the land into residential lots and enter into a finished lot purchase and sale agreement with D.R. Horton. At March 31, 2019 and September 30, 2018 , accrued expenses and other liabilities on the Company's consolidated balance sheets included $1.7 million and $3.3 million owed to D.R. Horton for any accrued and unpaid shared services, land purchase contract deposits and due diligence and other development cost reimbursements.

Subsequent Event (Notes)

Subsequent Event (Notes)	6 Months Ended
	Mar. 31, 2019
Subsequent Event [Line Items]
Subsequent Events [Text Block]	Subsequent Event In April 2019 , the Company issued $350 million principal amount of 8.0% Senior Unsecured Notes (Notes) pursuant to Rule 144A and Regulation S under the Securities Act of 1933, as amended. The Notes are due April 15, 2024 with interest payable semi-annually, and represent senior unsecured obligations of Forestar and rank equally with the Company's other existing and future senior unsecured indebtedness. The annual effective interest rate of the Notes after giving effect to the amortization of financing costs is 8.5% .

Basis of Presentation (Policies

Basis of Presentation (Policies)	6 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited, consolidated financial statements include the accounts of Forestar Group Inc. (Forestar) and all of its 100% owned, majority-owned and controlled subsidiaries, which are collectively referred to as the "Company", "we", or "our", unless the context otherwise requires. The Company accounts for its investment in other entities in which it has significant influence over operations and financial policies using the equity method. The Company eliminates all material intercompany accounts and transactions. Noncontrolling interests in consolidated pass-through entities are recognized before income taxes. The financial statements have been prepared in accordance with U.S. Generally Accepted Accounting Principles (GAAP) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. In the opinion of management, these financial statements reflect all adjustments considered necessary to fairly state the results for the interim periods shown, including normal recurring accruals and other items. These financial statements, including the consolidated balance sheet as of September 30, 2018 , which was derived from audited financial statements, do not include all of the information and notes required by GAAP for complete financial statements and should be read in conjunction with the consolidated financial statements and accompanying notes included in the Company’s annual report on Form 10-KT for the nine months ended September 30, 2018 . The Company divested substantially all of its oil and gas working interest properties in 2016, and completed the sale of all oil and gas assets and related entities in 2017. As a result of selling the entities in 2017, the Company recognized a tax benefit during the six months ended March 31, 2018 that has been recorded as income from discontinued operations. There was no activity related to these discontinued operations during the three and six months ended March 31, 2019 . The transactions included in net income in the consolidated statements of operations are the same as those that would be presented in comprehensive income. Thus, the Company's net income equates to comprehensive income.
Reclassification, Policy [Policy Text Block]	Changes in Presentation and Reclassifications Certain items have been reclassified in the prior year financial statements to conform to the presentation and classifications used in the current year. Receivables, prepaid expenses, land purchase contract deposits, and intangible assets have been reclassified to other assets in the prior year consolidated balance sheet. Accrued employee compensation and benefits, accrued property taxes, accrued interest, other accrued expenses and other liabilities have been reclassified to accrued expenses and other liabilities in the prior year consolidated balance sheet. Other operating expense and general and administrative expense have been combined into one line item which is titled selling, general and administrative expense in the prior year consolidated statement of operations. In addition, certain items have been reclassified from selling, general and administrative expenses to cost of sales in the prior year statement of operations to conform to classifications used in the current year. The Company has reclassified the change in earnest money deposits in the prior year statement of cash flows from change in accounts payable and other accrued liabilities to conform to the classifications used in the current year. The Company has reclassified real estate cost of sales, real estate development and acquisition expenditures, reimbursements from utility and improvement districts, and other to change in real estate in the prior year statement of cash flows to conform to classifications used in the current year. The Company has reclassified proceeds from land and lot closings held for the Company’s benefit at title companies in the prior year consolidated balance sheet from receivables to cash and cash equivalents to conform to the classification used in the current year. These reclassifications had no effect on the Company's consolidated operating results, balance sheet or cash flows. In connection with the adoption of Accounting Standards Update (ASU) 2016-18 on October 1, 2018, restricted cash is included with cash and cash equivalents when reconciling beginning and ending cash amounts in the consolidated statements of cash flows. Prior period amounts have been reclassified to conform to the current year presentation, resulting in a decrease in cash used in financing activities of $39.7 million for the six months ended March 31, 2018 .
New Accounting Pronouncements and Changes in Accounting Principles [Text Block]	Adoption of New Accounting Standards On October 1, 2018, the Company adopted Accounting Standards Codification 606, "Revenue from Contracts with Customers" (ASC 606), which is a comprehensive new revenue recognition model that requires revenue to be recognized in a manner to depict the transfer of goods or services and satisfaction of performance obligations to a customer at an amount that reflects the consideration expected to be received in exchange for those goods or services. The Company applied the modified retrospective method to contracts that were not completed as of October 1, 2018. Results for the reporting period beginning on October 1, 2018 are presented under ASC 606, while prior period amounts were not adjusted and will continue to be reported under the previous accounting standards. Under ASC 606, the Company's performance obligations are typically satisfied at closing. However, there may be instances in which the Company has an unsatisfied remaining performance obligation at the time of closing. In these instances, the Company records contract liabilities and recognizes those revenues over time using the percentage of completion method based upon actual costs incurred. Generally, the Company's unsatisfied remaining performance obligations are expected to have an original duration of less than one year. As of October 1, 2018, the Company established contract liabilities of $6.4 million related to its remaining unsatisfied performance obligations at the time of adoption of ASC 606. There was no impact to the amount or timing of revenues recognized as a result of applying ASC 606 for the three and six months ended March 31, 2019 , and there have not been significant changes to the Company’s business processes, systems, or internal controls as a result of implementing the standard. A summary of items impacted as the result of adopting ASC 606 follows: As of March 31, 2019 As Reported Impact of Adoption As Adjusted (In millions) Real estate $ 851.5 $ 7.0 $ 844.5 Contract liabilities 7.9 7.9 — Deferred income 10.8 (0.9 ) 11.7 In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230), to address eight specific cash flow issues with the objective of reducing the existing diversity in practice. The updated standard is effective for financial statements issued for annual periods beginning after December 15, 2017 and interim periods within those fiscal years. The Company adopted the guidance as of October 1, 2018 and did not have a material impact on its consolidated statements of cash flows. In November 2016, the FASB issued ASU 2016-18, “Statement of Cash Flows - Restricted Cash,” which requires amounts generally described as restricted cash and restricted cash equivalents be included with cash and cash equivalents when reconciling the total beginning and ending amounts for the periods shown on the statement of cash flows. The Company adopted the guidance as of October 1, 2018 on a retrospective basis and made the required changes to its statements of cash flows as described in the “Changes in Presentation and Reclassifications” section above. In May 2017, the FASB issued ASU 2017-09, “Compensation - Stock Compensation: Scope of Modification Accounting,” which clarifies which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting. Under the new guidance, modification accounting is required if the fair value, vesting conditions or classification (equity or liability) of the new award are different from the original award immediately before the original award is modified. The Company adopted the guidance as of October 1, 2018 and did not have a material impact on its consolidated financial position, results of operations or cash flows.
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). This ASU requires lessees to put most leases on their balance sheets but recognize expenses on their income statements in a manner that is similar to today's accounting. This guidance also eliminates today's real estate-specific provisions for all entities. For lessors, the guidance modifies the classification criteria and the accounting for sales-type and direct financing leases. This guidance is effective for the Company on October 1, 2019 and early adoption is permitted. The new standard requires a modified retrospective transition approach for all leases existing at, or entered into after, the date of initial application, with an option to use certain transition relief. The Company is currently evaluating the effect the updated standard will have on our financial position, results of operations and cash flows.

Basis of Presentation (Tables)

Basis of Presentation (Tables)	6 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block]	A summary of items impacted as the result of adopting ASC 606 follows: As of March 31, 2019 As Reported Impact of Adoption As Adjusted (In millions) Real estate $ 851.5 $ 7.0 $ 844.5 Contract liabilities 7.9 7.9 — Deferred income 10.8 (0.9 ) 11.7

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
Assets Allocated by Segment	Total assets by segment at September 30, 2018 are as follows: September 30, 2018 Real Estate Other Items Not Allocated Consolidated (In millions) Cash and cash equivalents $ — $ — $ 318.8 $ 318.8 Restricted cash — — 16.2 16.2 Real estate 498.0 — — 498.0 Investment in unconsolidated ventures 11.7 — — 11.7 Income taxes receivable — — 4.4 4.4 Property and equipment, net — 1.5 0.2 1.7 Deferred tax asset, net — — 26.9 26.9 Other assets 12.4 0.4 2.6 15.4 $ 522.1 $ 1.9 $ 369.1 $ 893.1
Segment Revenues and Earnings	Segment results for the three and six months ended March 31, 2018 are as follows: Three Months Ended March 31, 2018 Real Estate Other Items Not Allocated Consolidated (In millions) Revenues $ 22.6 $ — $ — $ 22.6 Cost of sales 15.6 0.6 — 16.2 Selling, general and administrative expense 1.6 — 3.8 5.4 Equity in earnings of unconsolidated ventures (1.5 ) — — (1.5 ) Gain on sale of assets (2.7 ) — — (2.7 ) Interest expense — — 2.1 2.1 Interest and other income (0.2 ) — (1.4 ) (1.6 ) Income (loss) from continuing operations before taxes $ 9.8 $ (0.6 ) $ (4.5 ) $ 4.7 Net income attributable to noncontrolling interests 0.1 — — 0.1 Income (loss) from continuing operations before taxes attributable to Forestar Group Inc. $ 9.7 $ (0.6 ) $ (4.5 ) $ 4.6 Six Months Ended March 31, 2018 Real Estate Other Items Not Allocated Consolidated (In millions) Revenues $ 53.5 $ — $ — $ 53.5 Cost of sales 32.4 6.5 — 38.9 Selling, general and administrative expense 7.5 0.1 22.0 29.6 Equity in earnings of unconsolidated ventures (8.5 ) — — (8.5 ) Gain on sale of assets (2.7 ) — — (2.7 ) Interest expense — — 4.2 4.2 Interest and other income (0.9 ) — (1.4 ) (2.3 ) Income (loss) from continuing operations before taxes $ 25.7 $ (6.6 ) $ (24.8 ) $ (5.7 ) Net income attributable to noncontrolling interests 2.0 — — 2.0 Income (loss) from continuing operations before taxes attributable to Forestar Group Inc. $ 23.7 $ (6.6 ) $ (24.8 ) $ (7.7 )

Real Estate (Tables)

Real Estate (Tables)	6 Months Ended
	Mar. 31, 2019
Real Estate [Abstract]
Real Estate	Real estate consists of: March 31, September 30, (In millions) Developed and under development projects $ 803.0 $ 463.1 Land held for development 48.5 34.9 $ 851.5 $ 498.0

Revenues (Tables)

Revenues (Tables)	6 Months Ended
	Mar. 31, 2019
Revenues [Abstract]
Revenue from External Customers by Products and Services [Table Text Block]	Revenues consist of: Three Months Ended March 31, Six Months Ended March 31, 2019 2018 2019 2018 (In millions) Residential lot sales $ 49.3 $ 20.4 $ 84.0 $ 41.5 Residential tract sales — — — 2.3 Commercial tract sales 15.0 2.0 18.5 9.2 Other 1.0 0.2 1.3 0.5 $ 65.3 $ 22.6 $ 103.8 $ 53.5

Investment in Unconsolidated _2

Investment in Unconsolidated Ventures (Tables)	6 Months Ended
	Mar. 31, 2019
Equity Method Investments and Joint Ventures [Abstract]
Summarized Financial Information	Combined summarized balance sheet information for our ventures accounted for using the equity method follows: March 31, September 30, (In millions) Assets: Cash and cash equivalents $ 1.7 $ 10.2 Real estate 13.7 17.2 Other assets 0.1 0.1 Total assets $ 15.5 $ 27.5 Liabilities and Equity: Accounts payable and other liabilities $ 0.3 $ 0.6 Equity 15.2 26.9 Total liabilities and equity $ 15.5 $ 27.5 Forestar's investment in unconsolidated ventures $ 7.4 $ 11.7 Combined summarized income statement information for our ventures accounted for using the equity method follows: Three Months Ended March 31, Six Months Ended March 31, 2019 2018 2019 2018 (In millions) Revenues $ — $ 3.4 $ 1.8 $ 12.0 Earnings — 4.3 1.4 21.7 Forestar's equity in earnings of unconsolidated ventures — 1.5 0.6 8.5

Other Assets, Accrued Expense_2

Other Assets, Accrued Expenses and Other Liabilities (Tables)	6 Months Ended
	Mar. 31, 2019
Other Assets, Accrued Expenses and Other Liabilities [Abstract]
Schedule of Other Assets [Table Text Block]	The Company's other assets at March 31, 2019 and September 30, 2018 were as follows: March 31, September 30, (In millions) Receivables, net $ 1.4 $ 2.7 Prepaid expenses 3.3 3.1 Land purchase contract deposits 6.7 4.1 Intangible assets — 0.5 Other assets 4.7 5.0 $ 16.1 $ 15.4
Schedule of Accrued Liabilities [Table Text Block]	The Company's accrued expenses and other liabilities at March 31, 2019 and September 30, 2018 were as follows: March 31, September 30, (In millions) Accrued employee compensation and benefits $ 5.8 $ 6.7 Accrued property taxes 0.4 1.7 Accrued interest 0.4 0.4 Contract liabilities 7.9 — Deferred income 10.8 11.6 Other accrued expenses 26.4 27.2 Other liabilities 2.8 2.0 $ 54.5 $ 49.6

Debt (Tables)

Debt (Tables)	6 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Debt	Debt consists of: March 31, September 30, (In millions) 3.75% convertible senior notes due 2020, net of discount and fees $ 114.2 $ 111.7 Senior unsecured revolving credit facility, maturing 2021 35.0 — $ 149.2 $ 111.7

Fair Value (Tables)

Fair Value (Tables)	6 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements, Not Measured at Fair Value	For the financial assets and liabilities that the Company does not reflect at fair value, the following tables present both their respective carrying value and fair value at March 31, 2019 and September 30, 2018 . Fair Value at March 31, 2019 Carrying Value Level 1 Level 2 Level 3 Total (in millions) Cash and cash equivalents (a) $ 66.4 $ 66.4 $ — $ — $ 66.4 Restricted cash (a) 15.7 15.7 — — 15.7 Debt (b) (c) 149.6 — 115.1 35.0 150.1 Fair Value at September 30, 2018 Carrying Value Level 1 Level 2 Level 3 Total (in millions) Cash and cash equivalents (a) $ 318.8 $ 318.8 $ — $ — $ 318.8 Restricted cash (a) 16.2 16.2 — — 16.2 Debt (b) (c) 112.4 — 113.2 — 113.2 _____________________ (a) The fair values of cash, cash equivalents and restricted cash approximate their carrying values due to their short-term nature and are classified as Level 1 within the fair value hierarchy. (b) The fair value of the senior notes is determined based on quoted prices, which is classified as Level 2 within the fair value hierarchy. (c) The fair value of borrowings under the revolving credit facility approximate carrying value due to the floating interest rate terms and is classified as Level 3 within the fair value hierarchy.
Fair Value Measurements, Nonrecurring	Non-financial assets measured at fair value on a non-recurring basis are as follows: March 31, 2019 September 30, 2018 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total (In millions) Non-financial Assets: Real estate $ — $ — $ — $ — $ — $ 0.2 $ — $ 0.2

Net Income (Loss) per Share (Ta

Net Income (Loss) per Share (Tables)	6 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Earnings Attributable to Common Shareholders and Weighted Average Common Shares Outstanding	The computations of basic and diluted earnings per share are as follows: Three Months Ended March 31, Six Months Ended March 31, 2019 2018 2019 2018 (In millions, except share data) Numerator: Continuing operations Net income (loss) from continuing operations $ 12.8 $ 4.6 $ 16.7 $ (18.3 ) Less: Net income attributable to noncontrolling interest 2.7 0.1 3.3 2.0 Net income (loss) from continuing operations attributable to Forestar Group Inc. $ 10.1 $ 4.5 $ 13.4 $ (20.3 ) Discontinued operations Net income from discontinued operations available for diluted earnings per share $ — $ — $ — $ 7.2 Denominator: Weighted average common shares outstanding — basic 41,959,866 41,938,936 41,956,179 41,948,180 Dilutive effect of share based compensation 6,233 27,430 6,220 13,715 Total weighted average shares outstanding — diluted 41,966,099 41,966,366 41,962,399 41,961,895 Anti-dilutive awards excluded from diluted weighted average shares — — — 15,434

Basis of Presentation Details (

Basis of Presentation Details (Details) - USD ($) $ in Millions	Oct. 05, 2017	Mar. 31, 2018	Mar. 31, 2019	Oct. 01, 2018	Sep. 30, 2018
Entity Information [Line Items]
Real estate			$ 851.5		$ 498
Contract with Customer, Liability			7.9	$ 6.4	0
Deferred income			10.8		$ 11.6
Majority Shareholder [Member] | D.R. Horton, Inc. [Member]
Entity Information [Line Items]
Sale of Stock, Percentage of Ownership after Transaction	75.00%
Accounting Standards Update 2016-18 [Member]
Entity Information [Line Items]
Increase (Decrease) in Restricted Cash		$ (39.7)
Accounting Standards Update 2014-09 [Member]
Entity Information [Line Items]
Real estate			7
Contract with Customer, Liability			7.9
Deferred income			(0.9)
Pro Forma [Member] | Accounting Standards Update 2014-09 [Member]
Entity Information [Line Items]
Real estate			844.5
Contract with Customer, Liability			0
Deferred income			11.7
D.R. Horton, Inc. [Member] | Land and Land Improvements [Member]
Entity Information [Line Items]
Contract with Customer, Liability			$ 7.9

Segment Information - Additiona

Segment Information - Additional Information (Detail)	6 Months Ended
	Mar. 31, 2019segment
Segment Reporting [Abstract]
Number of business segments	1

Segment Information - Assets Al

Segment Information - Assets Allocated by Segment (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Cash and cash equivalents	$ 66.4	$ 318.8
Restricted cash	15.7	16.2
Real estate	851.5	498
Investment in unconsolidated ventures	7.4	11.7
Income taxes receivable	2.5	4.4
Property and equipment, net	2.4	1.7
Deferred tax asset, net	22.9	26.9
Other assets	16.1	15.4
Total Assets	$ 984.9	893.1
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Cash and cash equivalents		318.8
Restricted cash		16.2
Real estate		0
Investment in unconsolidated ventures		0
Income taxes receivable		4.4
Property and equipment, net		0.2
Deferred tax asset, net		26.9
Other assets		2.6
Total Assets		369.1
Real Estate [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Cash and cash equivalents		0
Restricted cash		0
Real estate		498
Investment in unconsolidated ventures		11.7
Income taxes receivable		0
Property and equipment, net		0
Deferred tax asset, net		0
Other assets		12.4
Total Assets		522.1
Other [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Cash and cash equivalents		0
Restricted cash		0
Real estate		0
Investment in unconsolidated ventures		0
Income taxes receivable		0
Property and equipment, net		1.5
Deferred tax asset, net		0
Other assets		0.4
Total Assets		$ 1.9

Segment Information - Segment R

Segment Information - Segment Revenues and Earnings (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Revenues	$ 65.3	$ 22.6	$ 103.8	$ 53.5
Cost of sales	43.6	16.2	74.3	38.9
Selling, general and administrative expense	6.2	5.4	11.9	29.6
Equity in earnings of unconsolidated ventures	0	(1.5)	(0.6)	(8.5)
Gain (Loss) on Disposition of Assets	0	2.7	0.9	2.7
Interest expense	0	2.1	0	4.2
Interest and other income	(0.9)	(1.6)	(2.2)	(2.3)
Income (loss) from continuing operations before taxes	16.4	4.7	21.3	(5.7)
Net income attributable to noncontrolling interests	$ 2.7	0.1	$ 3.3	2
Income (loss) from continuing operations before taxes attributable to Forestar Group Inc.		4.6		(7.7)
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Revenues		0		0
Cost of sales		0		0
Selling, general and administrative expense		3.8		22
Equity in earnings of unconsolidated ventures		0		0
Gain (Loss) on Disposition of Assets		0		0
Interest expense		2.1		4.2
Interest and other income		(1.4)		(1.4)
Income (loss) from continuing operations before taxes		(4.5)		(24.8)
Net income attributable to noncontrolling interests		0		0
Income (loss) from continuing operations before taxes attributable to Forestar Group Inc.		(4.5)		(24.8)
Real Estate [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues		22.6		53.5
Cost of sales		15.6		32.4
Selling, general and administrative expense		1.6		7.5
Equity in earnings of unconsolidated ventures		(1.5)		(8.5)
Gain (Loss) on Disposition of Assets		2.7		2.7
Interest expense		0		0
Interest and other income		(0.2)		(0.9)
Income (loss) from continuing operations before taxes		9.8		25.7
Net income attributable to noncontrolling interests		0.1		2
Income (loss) from continuing operations before taxes attributable to Forestar Group Inc.		9.7		23.7
Other [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues		0		0
Cost of sales		0.6		6.5
Selling, general and administrative expense		0		0.1
Equity in earnings of unconsolidated ventures		0		0
Gain (Loss) on Disposition of Assets		0		0
Interest expense		0		0
Interest and other income		0		0
Income (loss) from continuing operations before taxes		(0.6)		(6.6)
Net income attributable to noncontrolling interests		0		0
Income (loss) from continuing operations before taxes attributable to Forestar Group Inc.		$ (0.6)		$ (6.6)

Real Estate - Real Estate (Deta

Real Estate - Real Estate (Details) - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2019	Sep. 30, 2018
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Payments to Acquire Residential Real Estate	$ 300.2
Payments to Develop Real Estate Assets	119.1
Real estate	851.5	$ 498
Developed and under development projects
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Real estate	803	463.1
Land [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Real estate	$ 48.5	$ 34.9
Minimum [Member] | D.R. Horton, Inc. [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Investment Interest Rate	12.00%
Maximum [Member] | D.R. Horton, Inc. [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Investment Interest Rate	16.00%

Revenues (Details)

Revenues (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Oct. 01, 2018	Sep. 30, 2018
Revenue from External Customer [Line Items]
Contract with Customer, Liability	$ 7.9		$ 7.9		$ 6.4	$ 0
Deferred income	10.8		10.8			$ 11.6
Other	1	$ 0.2	1.3	$ 0.5
Revenue, Net	65.3	22.6	103.8	53.5
Retail Land Sales, Improvement Revenue, Prior Sales	2.1		3
Residential Real Estate [Member]
Revenue from External Customer [Line Items]
Residential lot sales	49.3	20.4	84	41.5
Tract sales	0	0	0	2.3
Commercial Real Estate [Member]
Revenue from External Customer [Line Items]
Tract sales	15	$ 2	18.5	$ 9.2
D.R. Horton, Inc. [Member] | Land and Land Improvements [Member]
Revenue from External Customer [Line Items]
Contract with Customer, Liability	$ 7.9		$ 7.9

Investment in Unconsolidated _3

Investment in Unconsolidated Ventures - Additional Information (Detail)	Mar. 31, 2019venture
Schedule of Equity Method Investments [Line Items]
Number of ventures under ownership interest using equity method	4
Variable Interest Entity, Primary Beneficiary
Schedule of Equity Method Investments [Line Items]
Number of ventures that are a VIE	0

Investment in Unconsolidated _4

Investment in Unconsolidated Ventures - Summarized Balance Sheet Information (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Sep. 30, 2018
Equity Method Investment, Summarized Financial Information, Assets [Abstract]
Equity Method Investment, Summarized Financial Information, Assets	$ 15.5	$ 27.5
Equity Method Investment, Summarized Financial Information, Liabilities and Equity [Abstract]
Equity Method Investment, Summarized Financial Information, Liabilities and Equity	15.5	27.5
Investment in unconsolidated ventures	7.4	11.7
Cash and cash equivalents
Equity Method Investment, Summarized Financial Information, Assets [Abstract]
Equity Method Investment, Summarized Financial Information, Assets	1.7	10.2
Real estate
Equity Method Investment, Summarized Financial Information, Assets [Abstract]
Equity Method Investment, Summarized Financial Information, Assets	13.7	17.2
Other assets
Equity Method Investment, Summarized Financial Information, Assets [Abstract]
Equity Method Investment, Summarized Financial Information, Assets	0.1	0.1
Accounts Payable and Accrued Liabilities [Member]
Equity Method Investment, Summarized Financial Information, Liabilities and Equity [Abstract]
Equity Method Investment, Summarized Financial Information, Liabilities	0.3	0.6
Equity
Equity Method Investment, Summarized Financial Information, Liabilities and Equity [Abstract]
Equity Method Investment Summarized Financial Information, Equity	$ 15.2	$ 26.9

Investment in Unconsolidated _5

Investment in Unconsolidated Ventures - Summarized Income Statement Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Schedule of Equity Method Investments [Line Items]
Revenues	$ 0	$ 3.4	$ 1.8	$ 12
Earnings (loss)	0	4.3	1.4	21.7
Gain (Loss) on Disposition of Assets	0	2.7	0.9	2.7
Equity in earnings of unconsolidated ventures	$ 0	$ 1.5	$ 0.6	$ 8.5
Equity Method Investments [Member] | CREA FMF [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage		30.00%		30.00%
Proceeds from Sale of Real Estate				$ 71.7
Gain (Loss) on Disposition of Assets				19
Equity in earnings of unconsolidated ventures				$ 7.8

Discontinued Operations (Summar

Discontinued Operations (Summarized Results from Discontinued Operations) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Discontinued Operations and Disposal Groups [Abstract]
Income from discontinued operations, net of taxes	$ 0	$ 0	$ 0	$ 7.2

Other Assets, Accrued Expense_3

Other Assets, Accrued Expenses and Other Liabilities (Detail) $ in Millions	Mar. 31, 2019USD ($)Lot	Oct. 01, 2018USD ($)	Sep. 30, 2018USD ($)
Segment Reporting Information [Line Items]
Receivables, net	$ 1.4		$ 2.7
Prepaid expenses	3.3		3.1
Land purchase contract deposits	6.7		4.1
Intangible assets	0		0.5
Other assets	4.7		5
Total Other assets	16.1		15.4
Accrued employee compensation and benefits	5.8		6.7
Accrued property taxes	0.4		1.7
Accrued interest	0.4		0.4
Contract liabilities	7.9	$ 6.4	0
Deferred income	10.8		11.6
Other accrued expenses	26.4		27.2
Other liabilities	2.8		2
Total Accrued expenses and other liabilities	$ 54.5		$ 49.6
Number of Units in Real Estate Property | Lot	31,400
Land and Land Improvements [Member] | D.R. Horton, Inc. [Member]
Segment Reporting Information [Line Items]
Contract liabilities	$ 7.9
Number of Units in Real Estate Property | Lot	261

Debt, net - Schedule of Debt (D

Debt, net - Schedule of Debt (Detail) - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2019	Sep. 30, 2018
Debt Instrument [Line Items]
Debt, net	$ 149.2	$ 111.7
Long-term Line of Credit	35	0
3.75% convertible senior notes due 2020, net of discount
Debt Instrument [Line Items]
Debt, net	$ 114.2	$ 111.7
Debt instrument, maturity date	Mar. 1, 2020
Interest rate percentage	3.75%	3.75%

Debt, net - Additional Informat

Debt, net - Additional Information (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Sep. 30, 2018
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity	$ 380
Line of Credit Facility, Accordion Amount	190
Line of Credit Facility, Maximum Borrowing Capacity	$ 570
Letter of Credit, Maximum Borrowing Capacity	50.00%
Long-term Line of Credit	$ 35	$ 0
Line of Credit Facility, Interest Rate at Period End	4.80%
Deferred finance costs, net	$ 0.4	$ 0.7
3.75% convertible senior notes due 2020, net of discount
Debt Instrument [Line Items]
Debt Instrument, Face Amount	118.9
Debt Instrument, Unamortized Discount	$ 4.3
Effective interest rate of liability component	8.00%
Debt Instrument, Convertible, Carrying Amount of Equity Component	$ 16.8
Interest rate percentage	3.75%	3.75%
Line of Credit [Member]
Debt Instrument [Line Items]
Letters of credit outstanding	$ 3.8

Fair Value Measurements, Not Me

Fair Value Measurements, Not Measured at Fair Value (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Sep. 30, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 66.4	$ 318.8
Restricted cash	15.7	16.2
Debt, net	149.2	111.7
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	66.4	318.8
Other Assets, Fair Value Disclosure	15.7	16.2
Long-term Debt, Fair Value	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Other Assets, Fair Value Disclosure	0	0
Long-term Debt, Fair Value	115.1	113.2
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Other Assets, Fair Value Disclosure	0	0
Long-term Debt, Fair Value	35	0
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	66.4	318.8
Other Assets, Fair Value Disclosure	15.7	16.2
Long-term Debt, Fair Value	150.1	113.2
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, net	$ 149.6	$ 112.4

Fair Value Disclosures, Non-rec

Fair Value Disclosures, Non-recurring (Detail) - Real Estate [Member] - Fair Value, Measurements, Nonrecurring - USD ($) $ in Millions	Mar. 31, 2019	Sep. 30, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure, nonrecurring	$ 0	$ 0.2
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure, nonrecurring	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure, nonrecurring	0	0.2
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure, nonrecurring	$ 0	$ 0

Net Income (Loss) per Share - E

Net Income (Loss) per Share - Earnings Attributable to Common Shareholders and Weighted Average Common Shares Outstanding (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Continuing operations
Net income (loss) from continuing operations	$ 12.8	$ 4.6	$ 16.7	$ (18.3)
Less: Net income attributable to noncontrolling interests	2.7	0.1	3.3	2
Net income (loss) attributable to Forestar Group Inc.	10.1	4.5	13.4	(20.3)
Discontinued operations
Income from discontinued operations, net of taxes	$ 0	$ 0	$ 0	$ 7.2
Denominator:
Weighted average common shares outstanding — basic	41,959,866	41,938,936	41,956,179	41,948,180
Dilutive effect of share based compensation	6,233	27,430	6,220	13,715
Total weighted average shares outstanding — diluted	41,966,099	41,966,366	41,962,399	41,961,895
Anti-dilutive awards excluded from diluted weighted average shares (in shares)	0	0	0	15,434

Net Income (Loss) per Share - A

Net Income (Loss) per Share - Additional Information (Detail)	Mar. 31, 2019$ / shares
3.75% convertible senior notes due 2020, net of discount
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Conversion price of convertible notes	$ 51.42

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	Oct. 05, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Sep. 30, 2018
Effective income tax rate, percent		22.00%	1.00%	22.00%	221.00%
Deferred Tax Assets, Net Of Deferred Tax Liabilities		$ 26.2		$ 26.2		$ 30.3
Valuation allowance, deferred tax asset, amount		3.3		3.3		$ 3.4
Unrecognized tax benefits		$ 1.1		$ 1.1
Majority Shareholder [Member] | D.R. Horton, Inc. [Member]
Sale of Stock, Percentage of Ownership after Transaction	75.00%

Commitments and Contingencies N

Commitments and Contingencies Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2019	Sep. 30, 2018
Loss Contingencies [Line Items]
Special Assessment Bond	$ 95.6
Restricted cash	15.7	$ 16.2
Standby Letters of Credit [Member] | Keybank National Association [Member]
Loss Contingencies [Line Items]
Letters of Credit Outstanding, Amount	$ 15

Related Party Transactions (Det

Related Party Transactions (Details)	3 Months Ended		6 Months Ended
	Mar. 31, 2019USD ($)Lot	Mar. 31, 2018USD ($)	Mar. 31, 2019USD ($)Lot	Mar. 31, 2018USD ($)	Oct. 01, 2018USD ($)	Sep. 30, 2018USD ($)
Related Party Transaction [Line Items]
Number of Units in Real Estate Property | Lot	31,400		31,400
Due to Related Parties, Current	$ 1,700,000		$ 1,700,000			$ 3,300,000
Contract with Customer, Liability	7,900,000		7,900,000		$ 6,400,000	0
Real estate	$ 851,500,000		851,500,000			498,000,000
D.R. Horton, Inc. [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Selling, General and Administrative Expenses from Transactions with Related Party			1,000,000	$ 300,000
General and Administrative Expense [Member] | D.R. Horton, Inc. [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Expenses from Transactions with Related Party			$ 600,000	$ 400,000
D.R. Horton, Inc. [Member]
Related Party Transaction [Line Items]
Number of Lots Sold	453	183	908	183
Revenue from Related Parties	$ 37,700,000	$ 8,500,000	$ 70,200,000	$ 8,500,000
Under Contract [Member] | D.R. Horton, Inc. [Member]
Related Party Transaction [Line Items]
Number of Units in Real Estate Property | Lot	12,100		12,100
Related Party Deposit Liabilities	$ 76,200,000		$ 76,200,000			45,300,000
Right of First Offer [Member] | D.R. Horton, Inc. [Member]
Related Party Transaction [Line Items]
Number of Units in Real Estate Property | Lot	9,600		9,600
Land and Land Improvements [Member]
Related Party Transaction [Line Items]
Real estate	$ 803,000,000		$ 803,000,000			463,100,000
Land [Member]
Related Party Transaction [Line Items]
Real estate	48,500,000		48,500,000			$ 34,900,000
Other Expense [Member] | D.R. Horton, Inc. [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	700,000	5,900,000	3,700,000	8,200,000
Deposits [Member] | D.R. Horton, Inc. [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	$ 4,700,000	$ 11,800,000	$ 16,800,000	$ 14,000,000
Land and Land Improvements [Member] | D.R. Horton, Inc. [Member]
Related Party Transaction [Line Items]
Number of Units in Real Estate Property | Lot	261		261
Contract with Customer, Liability	$ 7,900,000		$ 7,900,000
Minimum [Member] | D.R. Horton, Inc. [Member]
Related Party Transaction [Line Items]
Investment Interest Rate			12.00%
Maximum [Member] | D.R. Horton, Inc. [Member]
Related Party Transaction [Line Items]
Investment Interest Rate			16.00%

Subsequent Event (Details)

Subsequent Event (Details) - Senior Notes [Member] - Subsequent Event [Member] $ in Millions	Jun. 30, 2019USD ($)
Subsequent Event [Line Items]
Debt Instrument, Face Amount	$ 350
Interest rate percentage	8.00%
Debt Instrument, Interest Rate, Effective Percentage	8.50%