Notes receivable interest rate.

No definition available.

Name:	geos_NotesReceivableInterestRate
Namespace Prefix:	geos_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Promissory notes receivable maturity month and year.

+ References

No definition available.

+ Details

Name:	geos_PromissoryNotesReceivableMaturityMonthAndYear
Namespace Prefix:	geos_
Data Type:	xbrli:gYearMonthItemType
Balance Type:	na
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

No definition available.

+ Details

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

- Definition

Description of the frequency of periodic payments (monthly, quarterly, annual).

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Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

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+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the required periodic payments including both interest and principal payments.

+ References

+ Details

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

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of decrease from sale and reclassification to held-for-sale of financing receivable.

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+ Details

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

- Definition

Amount, before allowance for credit loss, of financing receivable.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Trade Accounts and Notes Receivable - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2020	Mar. 31, 2020	Mar. 31, 2021
Accounts Notes And Loans Receivable [Line Items]
Promissory notes receivable maturity month and year			2023-01
Secured Promissory Note
Accounts Notes And Loans Receivable [Line Items]
Value of notes with customer		$ 10.0
Term of the notes		3 years
Monthly principal and interest payments		$ 0.3
Frequency of payments		monthly	monthly
Short-Term Promissory Note
Accounts Notes And Loans Receivable [Line Items]
Value of notes with customer	$ 13.2
Interest rate of the notes	8.00%
Maturity date	Mar. 31, 2021
Manufactured Rental Equipment
Accounts Notes And Loans Receivable [Line Items]
Promissory notes receivable maximum interest rate			8.00%
Product
Accounts Notes And Loans Receivable [Line Items]
Partially financed product sale		$ 12.5