SHAREHOLDERS' DEFICIT - Warrants (Details)		12 Months Ended
Jun. 27, 2024 $ / shares	Dec. 31, 2025 D $ / shares shares
SHAREHOLDERS' DEFICIT
Warrants outstanding \| shares		17,500,000
Number of days after completion of business combination, Warrants are exercisable		30 days
Threshold number of days after closing of business combination for filing with SEC		20 days
Exercise price of warrants (in dollar per share)		$ 11.5
Expiry of warrants term		5 years
Effective issue price for adjustment of exercise price of warrants		$ 9.2
Percentage of gross new proceeds to total equity proceeds		60.00%
Threshold trading days for for adjustment of exercise price of warrants \| D		20
Warrant exercise price adjustment (in percentage)		115.00%
Redemption trigger price		$ 18
Warrant redemption price adjustment (in percentage)		180.00%
Threshold consecutive days for transfer, assign or sale of shares or warrants, after the completion of the initial business combination		30 days
Notice period of redemption		30 days
Redemption price per public warrant (in dollars per share)		$ 18
Trading days for redemption of warrants \| D		20
Consecutive trading days for redemption of warrants		30 days
Public Warrants
SHAREHOLDERS' DEFICIT
Warrants outstanding \| shares		11,500,000
Redemption price per public warrant (in dollars per share)		$ 0.01
Private Placement Warrants
SHAREHOLDERS' DEFICIT
Warrants outstanding \| shares		6,000,000
Exercise price of warrants (in dollar per share)	$ 11.5
Threshold consecutive days for transfer, assign or sale of shares or warrants, after the completion of the initial business combination	30 days

Represents the percentage of adjustment of redemption price of stock based on market value and newly issued price.

No definition available.

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- Definition

Represents the effective issuance price of shares for adjustment of exercise price of warrants.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Represents the adjustment percentage for exercise price of warrants.

+ References

No definition available.

+ Details

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- Definition

Represents the minimum written notice period of redemption of warrants.

+ References

No definition available.

+ Details

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- Definition

Number of days after completion of a Business Combination after which warrants or rights are exercisable.

+ References

No definition available.

+ Details

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- Definition

Represents the percentage of gross proceeds to total equity proceeds used to measure adjustment of exercise price of warrants.

+ References

No definition available.

+ Details

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Namespace Prefix:	graf_
Data Type:	dtr-types:percentItemType
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Period Type:	duration

- Definition

Represents the consecutive trading days for redemption of warrants for cash after completion of initial business combination.

+ References

No definition available.

+ Details

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- Definition

Represents the trading days for redemption of warrants for cash after completion of initial business combination.

+ References

No definition available.

+ Details

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Namespace Prefix:	graf_
Data Type:	xbrli:integerItemType
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Period Type:	duration

- Definition

The redemption price per share or per unit of warrants or rights outstanding.

+ References

No definition available.

+ Details

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Namespace Prefix:	graf_
Data Type:	dtr-types:perShareItemType
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Period Type:	duration

- Definition

The minimum trading price for the reporting entity's stock which must be achieved as a condition for redemption of the warrant.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:perShareItemType
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Period Type:	duration

- Definition

The lock in period after the completion of initial business combination for the sponsor and other officers for the warrants issued .

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Represents the threshold trading day period for adjustment of exercise price of warrants.

+ References

No definition available.

+ Details

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Namespace Prefix:	graf_
Data Type:	xbrli:integerItemType
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Period Type:	duration

- Definition

Maximum number of days after closing of business combination, the Company will use commercially reasonable efforts to file with the SEC.

+ References

No definition available.

+ Details

Name:	graf_ThresholdNumberOfBusinessDaysAfterClosingOfBusinessCombinationForFilingWithSec
Namespace Prefix:	graf_
Data Type:	xbrli:durationItemType
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- Definition

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

+ References

Reference 1: 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 2: 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

Reference 3: 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

+ Details

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

- Definition

Number of warrants or rights outstanding.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Period between issuance and expiration of outstanding warrant and right embodying unconditional obligation requiring redemption by transferring asset at specified or determinable date or upon event certain to occur, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (bbb)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

+ Details

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Period Type:	instant

- Details

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- Details

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