Other Charges - Restructuring Provision (Details) $ in Thousands	12 Months Ended
Jan. 31, 2026 USD ($)
Fiscal 2025 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Balance	$ 162
Accruals and adjustments	80
Cash draw downs	(242)
Fiscal 2026 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Accruals and adjustments	4,505
Cash draw downs	(4,454)
Effect of movements in foreign exchange and other	12
Balance	63
Workforce Reduction \| Fiscal 2025 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Balance	162
Accruals and adjustments	80
Cash draw downs	(242)
Workforce Reduction \| Fiscal 2026 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Accruals and adjustments	4,222
Cash draw downs	(4,171)
Effect of movements in foreign exchange and other	12
Balance	63
Office Closures \| Fiscal 2026 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Accruals and adjustments	225
Cash draw downs	(225)
Other \| Fiscal 2026 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Accruals and adjustments	58
Cash draw downs	$ (58)

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482017/420-10-50-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 17
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-17

+ Details

Name:	us-gaap_PaymentsForRestructuring
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- 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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4.d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479823/420-10-S99-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4.b.1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479823/420-10-S99-2

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4.b.2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479823/420-10-S99-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482017/420-10-50-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482017/420-10-50-1

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482017/420-10-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482017/420-10-50-1

+ Details

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

- Definition

Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

+ References

+ Details

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

- Definition

Amount of expense (reversal of expense) which increases (decreases) the restructuring reserve from an adjustment to a previously accrued restructuring liability.

+ References

+ Details

Name:	us-gaap_RestructuringReserveAccrualAdjustment1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of foreign currency translation gain (loss) which decreases (increases) the restructuring reserve.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4.b.2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479823/420-10-S99-2

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482017/420-10-50-1

+ Details

Name:	us-gaap_RestructuringReserveTranslationAdjustment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_RestructuringPlanAxis=dsgx_Fiscal2025RestructuringPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringPlanAxis=dsgx_Fiscal2026RestructuringPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=us-gaap_EmployeeSeveranceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=us-gaap_FacilityClosingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=us-gaap_OtherRestructuringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: