XML 22 R98.htm IDEA: XBRL DOCUMENT
v3.19.3

Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Sep. 30, 2019 | Sep. 30, 2018
Valuation And Qualifying Accounts Disclosure [Line Items] |  |
Balance at Beginning of Period | $ 1,453 |
Balance at Beginning of Period | 30,551 |
Charged to Costs and Expenses, net of Recoveries | 436 | $ 1,009
Balance at End of Period | 951 | 1,453
Balance at End of Period | 32,050 | 30,551
Inventory Obsolescence Reserve |  |
Valuation And Qualifying Accounts Disclosure [Line Items] |  |
Balance at Beginning of Period | 30,551 | 29,614
Charged to Costs and Expenses | 4,614 | 4,353
(Deductions) and Additions | (3,115) | (3,416)
Balance at End of Period | 32,050 | 30,551
Allowance for Doubtful Accounts on Accounts and Financing Receivables |  |
Valuation And Qualifying Accounts Disclosure [Line Items] |  |
Balance at Beginning of Period | 3,302 | 2,415
Charged to Costs and Expenses, net of Recoveries | 436 | 1,009
(Deductions) and Additions | (2,787) | (122)
Balance at End of Period | $ 951 | $ 3,302

X
- Definition Provision for (recovery) of doubtful accounts. + References No definition available. + Details
Name: | geos_ProvisionForRecoveryOfDoubtfulAccounts
Namespace Prefix: | geos_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- 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: | srt_ValuationAndQualifyingAccountsDisclosureLineItems
Namespace Prefix: | srt_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of allowance for credit loss on accounts receivable, classified as current. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(4) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5074-111524 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=118955202&loc=SL82895884-210446 + Details
Name: | us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of valuation reserve for inventory. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 330 -SubTopic 10 -Section 35 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=116846819&loc=d3e3927-108312 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 330 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SAB TOPIC 5.BB) -URI http://asc.fasb.org/extlink&oid=27011343&loc=d3e100047-122729 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.6(a)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_InventoryValuationReserves
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of loss from reductions in inventory due to subsequent measurement adjustments, including, but not limited to, physical deterioration, obsolescence, or changes in price levels. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 330 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=116847112&loc=d3e4542-108314 + Details
Name: | us-gaap_InventoryWriteDown
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of increase (decrease) in valuation and qualifying accounts and reserves. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690 + Details
Name: | us-gaap_ValuationAllowancesAndReservesPeriodIncreaseDecrease
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_ChangeInAccountingEstimateByTypeAxis=us-gaap_InventoryValuationAndObsolescenceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ValuationAllowancesAndReservesTypeAxis=geos_AllowanceForDoubtfulAccountsOnAccountsAndFinancingReceivablesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |