Real Estate - Real Estate (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Carrying value	$ 633,758	$ 607,133
Less: accumulated depreciation	(30,233)	(31,377)
Total Real Estate	603,525	575,756
Radisson Hotel [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Carrying value	61,628	59,773
Less: accumulated depreciation	(27,536)	(29,062)
Net carrying value	34,092	30,711
Undeveloped land (includes land in entitlement) [Member] [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Carrying value	93,013	93,182
Less: accumulated depreciation	0	0
Net carrying value	93,013	93,182
Entitled, developed and under development projects [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Carrying value	345,181	321,273
Less: accumulated depreciation	0	0
Net carrying value	345,181	321,273
West Austin [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Carrying value	9,029	8,866
Less: accumulated depreciation	0	0
Net carrying value	9,029	8,866
Downtown Edge [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Carrying value	11,938	11,856
Less: accumulated depreciation	0	0
Net carrying value	11,938	11,856
Music Row [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Carrying value	8,265	7,675
Less: accumulated depreciation	0	0
Net carrying value	8,265	7,675
Dillon [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Carrying value	15,870	15,203
Less: accumulated depreciation	0	0
Net carrying value	15,870	15,203
Midtown [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Carrying value	34,933	33,293
Less: accumulated depreciation	(963)	(231)
Net carrying value	33,970	33,062
Eleven [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Carrying value	53,901	53,958
Less: accumulated depreciation	(1,734)	(576)
Net carrying value	52,167	53,382
Harbor Lakes [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Carrying value	0	2,054
Less: accumulated depreciation	0	(1,508)
Net carrying value	$ 0	$ 546

Carrying amount as of the balance sheet date, net of valuation allowances and impairment losses, of costs of land expected to be developed in the near term plus capitalized costs of development, for purposes of selling completed units to home buyers or commercial or industrial entities..

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 210.5-02.6(a))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Amount of accumulated depreciation pertaining to real estate investments for entities with a substantial portion of business acquiring and holding investment real estate.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 970

-SubTopic 360

-Section S99

-Paragraph 1

-Subparagraph (SX 210.12-28.FN4)

-URI http://asc.fasb.org/extlink&oid=6590653&loc=d3e638233-123024

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 10

-Section S99

-Paragraph 6

-Subparagraph (SX 210.5-04.(c) Schedule III)

-URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

Amount of real estate investment property which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.1(d))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

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

- Definition

Amount of real estate investment property, net of accumulated depreciation, which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

+ References

+ Details

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

- Details

Name:	us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=for_RadissonHotelMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=for_UndevelopedlandincludeslandinentitlementMemberMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=for_EntitleddevelopedandunderdevelopmentprojectsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=for_WestAustinMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=for_DowntownEdgeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=for_MusicRowMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=for_DillonMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=for_MidtownMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=for_ElevenMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=for_HarborLakesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: