The amount of transition fee to the advisory.

No definition available.

Name:	fgii_AdvisoryTransitionFeeAmount
Namespace Prefix:	fgii_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The advisory transition fee, as a percentage on consideration paid for business combination.

+ References

No definition available.

+ Details

Name:	fgii_AdvisoryTransitionFeePercent
Namespace Prefix:	fgii_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Option to purchase maximum number of additional units.

+ References

No definition available.

+ Details

Name:	fgii_MaximumNumberOfUnitsToBePurchaseOnOptionSharesAdditionalIssues
Namespace Prefix:	fgii_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The over allotment period within which the underwriter has to exercise the over allotment option.

+ References

No definition available.

+ Details

Name:	fgii_OverAllotmentPeriod
Namespace Prefix:	fgii_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of underwriter fee paid.

+ References

No definition available.

+ Details

Name:	fgii_UnderwriterFeePaid
Namespace Prefix:	fgii_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of reimbursement of expenses by underwriters.

+ References

No definition available.

+ Details

Name:	fgii_UnderwritersExpenseReimbursementAmount
Namespace Prefix:	fgii_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of underwriting discount.

+ References

No definition available.

+ Details

Name:	fgii_UnderwritingDiscountAmount
Namespace Prefix:	fgii_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The percentage of gross proceeds of the offering, entitled as underwriting discount.

+ References

No definition available.

+ Details

Name:	fgii_UnderwritingDiscountPercent
Namespace Prefix:	fgii_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage of over-allotment proceeds, entitled as underwriting fee.

+ References

No definition available.

+ Details

Name:	fgii_UnderwritingFeesPercent
Namespace Prefix:	fgii_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of units issued during the period.

+ References

No definition available.

+ Details

Name:	fgii_UnitsIssuedDuringPeriodSharesIssued
Namespace Prefix:	fgii_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of units issued during the period.

+ References

No definition available.

+ Details

Name:	fgii_UnitsIssuedDuringPeriodSharesNewIssues
Namespace Prefix:	fgii_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Exercise price per share or per unit of warrants or rights outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480738/235-10-S50-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(4))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

+ Details

Name:	us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash inflow from the additional capital contribution to the entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 14
-Subparagraph (a)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-14

+ Details

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

- Definition

Per share or per unit amount of equity securities issued.

+ References

No definition available.

+ Details

Name:	us-gaap_SharesIssuedPricePerShare
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
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_SubsidiarySaleOfStockLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=us-gaap_OverAllotmentOptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=fgii_PrivateWarrants15Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

COMMITMENTS AND CONTINGENCIES (Details) - USD ($)				3 Months Ended	6 Months Ended
COMMITMENTS AND CONTINGENCIES (Details) - USD ($)	Jan. 22, 2026	Jan. 20, 2026	Sep. 30, 2025	Mar. 31, 2026	Jun. 30, 2026	Jan. 23, 2026	Jan. 15, 2026
COMMITMENTS AND CONTINGENCIES
Price per unit issued		$ 10				$ 10
Underwriting discount, amount					$ 1,000,000
Advisory transition fee, percent			1.00%
Maximum
COMMITMENTS AND CONTINGENCIES
Advisory transition fee, amount			$ 3,000,000
Minimum
COMMITMENTS AND CONTINGENCIES
Advisory transition fee, amount			$ 1,000,000
Over-Allotment Option
COMMITMENTS AND CONTINGENCIES
Underwriter purchase option term		45 days			45 days
Option to purchase maximum number of additional units (in shares)		3,000,000
Number of units issued	2,750,000			2,750,000
Price per unit issued	$ 10	$ 10
Gross proceeds from issuance of units	$ 27,500,000
Underwriting discount, percent of gross proceeds					1.00%
Underwriting fee, percent					0.50%
Underwriter fee					$ 1,137,500
Units issued during period, shares, issued					227,500
Over-Allotment Option \| Maximum
COMMITMENTS AND CONTINGENCIES
Underwriting discount, amount					$ 1,000,000
Maximum expense reimbursement					$ 125,000
$15 Private Warrants
COMMITMENTS AND CONTINGENCIES
Exercise price per warrant (in dollars per share)		$ 15			$ 15		$ 15