Debentures (Details) - Schedule of aggregate principal annual payments of debentures $ in Thousands	Dec. 31, 2021 USD ($)
Schedule of aggregate principal annual payments of debentures [Abstract]
2022	$ 47,766
2023	47,766
2024	47,766
2025	54,506
2026	54,506
Total	$ 252,310

Aggregate principal annual payments of debentures.

No definition available.

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The amount of repayments of bonds within next fifth and thereafter financial year.

No definition available.

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Namespace Prefix:	forty_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The amount of repayments of bonds within next financial year.

No definition available.

Name:	forty_RepaymentsOfBondsWithinNextFinancialYear
Namespace Prefix:	forty_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The amount of repayments of bonds within next fourth financial year.

No definition available.

Name:	forty_RepaymentsOfBondsWithinNextFourthFinancialYear
Namespace Prefix:	forty_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The amount of repayments of bonds within next second financial year.

No definition available.

Name:	forty_RepaymentsOfBondsWithinNextSecondFinancialYear
Namespace Prefix:	forty_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The amount of repayments of bonds within next third financial year.

No definition available.

Name:	forty_RepaymentsOfBondsWithinNextThirdFinancialYear
Namespace Prefix:	forty_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

No definition available.

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Data Type:	xbrli:stringItemType
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Period Type:	duration