Investment in Unconsolidated Ventures - Summarized Balance Sheet Information (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Venture Assets	$ 266,354	$ 240,490
Venture Borrowings	123,508	102,247
Venture Equity	111,797	110,447
Investment in venture	65,381us-gaap_EquityMethodInvestments	65,005us-gaap_EquityMethodInvestments
242, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Venture Assets	35,556	33,021
Venture Borrowings	9,328	6,940
Venture Equity	22,253	21,789
Investment in venture	10,363	10,098
CL Ashton Woods [Member]
Schedule of Equity Method Investments [Line Items]
Venture Assets	12,649	13,269
Venture Borrowings	0	0
Venture Equity	9,479	11,453
Investment in venture	4,693	6,015
CL Realty [Member]
Schedule of Equity Method Investments [Line Items]
Venture Assets	7,965	7,960
Venture Borrowings	0	0
Venture Equity	7,899	7,738
Investment in venture	3,950	3,869
CREA FMF [Member]
Schedule of Equity Method Investments [Line Items]
Venture Assets	50,251	40,014
Venture Borrowings	40,648	29,660
Venture Equity	5,874	5,987
Investment in venture	5,403	5,516
Elan 99, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Venture Assets	12,060	10,070
Venture Borrowings	1	1
Venture Equity	10,333	9,643
Investment in venture	9,299	8,679
FMF Littleton [Member]
Schedule of Equity Method Investments [Line Items]
Venture Assets	32,765	26,953
Venture Borrowings	3,912	0
Venture Equity	24,737	24,435
Investment in venture	6,362	6,287
FMF Peakview [Member]
Schedule of Equity Method Investments [Line Items]
Venture Assets	45,457	43,638
Venture Borrowings	24,774	23,070
Venture Equity	17,462	17,464
Investment in venture	3,574	3,575
HM Stonewall Estates [Member]
Schedule of Equity Method Investments [Line Items]
Venture Assets	3,629	3,750
Venture Borrowings	33	669
Venture Equity	3,596	3,081
Investment in venture	1,982	1,752
LM Land Holdings [Member]
Schedule of Equity Method Investments [Line Items]
Venture Assets	30,487	25,561
Venture Borrowings	8,505	4,448
Venture Equity	19,750	18,500
Investment in venture	9,686	9,322
PSW Communities [Member]
Schedule of Equity Method Investments [Line Items]
Venture Assets	18,964	16,045
Venture Borrowings	12,870	10,515
Venture Equity	4,610	4,415
Investment in venture	4,097	3,924
Temco [Member]
Schedule of Equity Method Investments [Line Items]
Venture Assets	11,734	11,756
Venture Borrowings	0	0
Venture Equity	11,556	11,556
Investment in venture	5,778	5,778
Other ventures [Member]
Schedule of Equity Method Investments [Line Items]
Venture Assets	4,837	8,453
Venture Borrowings	23,437	26,944
Venture Equity	(25,752)	(25,614)
Investment in venture	$ 194	$ 190

Equity method investment, summarized financial information, borrowing.

No definition available.

Name:	for_EquityMethodInvestmentSummarizedFinancialInformationBorrowing
Namespace Prefix:	for_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ 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 210.5-02.12)

-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 323

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35755396&loc=d3e33749-111570

+ Details

Name:	us-gaap_EquityMethodInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of assets reported by an equity method investment of the entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 50

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=51717284&loc=SL51721683-107760

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 28

-Subparagraph (f)

-URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14064-108612

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(g))

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33912-111571

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph g

-Subparagraph 1, 2

-Article 4

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph w

-Article 1

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph bb

-Article 1

+ Details

Name:	us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of equity, including noncontrolling interest, reported by an equity method investment of the entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 28

-URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14064-108612

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 50

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=51717284&loc=SL51721683-107760

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 28

-Subparagraph (f)

-URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14064-108612

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.g)

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

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

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=for_ClAshtonWoodsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=for_ClRealtyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=for_CREAFMFMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=for_Elan99LLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=for_FMFLittletonMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=for_FmfPeakviewLlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=for_HmStonewallEstatesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=for_LmLandHoldingsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=for_OtherVenturesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=for_PSWCommunitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=for_TemcoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=for_TwoHundredFortyTwoLlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: