XML 86 R76.htm IDEA: XBRL DOCUMENT
v3.21.2

Commitments and Contingent Liabilities - Narrative (Details) $ in Thousands |  | 6 Months Ended |  |
--- | --- | --- | --- | ---
Mar. 13, 2019 USD ($) | Jun. 30, 2021 USD ($) company | Dec. 31, 2020 USD ($) | Jun. 05, 2017 company
Product Liability Contingency |  |  |  |
Litigation settlement amount |  | $ 30,000 |  |
Number of companies that received a general notice letter (company) | company |  |  |  | 140
Present value of remedial work |  | 1,100,000 |  |
Undiscovered remedial work |  | $ 1,700,000 |  |
Anticipated clean period |  | 13 years |  |
Number of potentially responsible parties included in agreement | company |  | 100 |  |
Accrual for environmental loss |  | $ 2,524 | $ 2,562 |
UPRR |  |  |  |
Product Liability Contingency |  |  |  |
Annual commitment amount | $ 8,000 |  |  |
UPRR |  |  |  |
Product Liability Contingency |  |  |  |
Litigation settlement amount | 50,000 |  |  |
Litigation settlement amount, current | 2,000 |  |  |
Litigation settlement amount, non-current | $ 48,000 |  |  |
Payment period | 6 years |  |  |

X
- Definition Litigation Settlement, Amount Awarded to Other Party, Current + References No definition available. + Details
Name: | fstr_LitigationSettlementAmountAwardedToOtherPartyCurrent
Namespace Prefix: | fstr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Litigation Settlement, Amount Awarded to Other Party, Non-Current + References No definition available. + Details
Name: | fstr_LitigationSettlementAmountAwardedToOtherPartyNonCurrent
Namespace Prefix: | fstr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Litigation Settlement Installment Payment Term + References No definition available. + Details
Name: | fstr_LitigationSettlementInstallmentPaymentTerm
Namespace Prefix: | fstr_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Long-term Purchase Commitment, Annual Commitment Amount + References No definition available. + Details
Name: | fstr_LongtermPurchaseCommitmentAnnualCommitmentAmount
Namespace Prefix: | fstr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Number Of Companies Receiving General Notice Letter + References No definition available. + Details
Name: | fstr_NumberOfCompaniesReceivingGeneralNoticeLetter
Namespace Prefix: | fstr_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of Potentially Responsible Parties Included in Agreement + References No definition available. + Details
Name: | fstr_NumberOfPotentiallyResponsiblePartiesIncludedInAgreement
Namespace Prefix: | fstr_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Present Value of Proposed Remedial Work + References No definition available. + Details
Name: | fstr_PresentValueOfProposedRemedialWork
Namespace Prefix: | fstr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Remedial Work Anticipated Clean Up Period + References No definition available. + Details
Name: | fstr_RemedialWorkAnticipatedCleanUpPeriod
Namespace Prefix: | fstr_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Undiscovered Remedial Work + References No definition available. + Details
Name: | fstr_UndiscoveredRemedialWork
Namespace Prefix: | fstr_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Total costs accrued as of the balance sheet date for environmental loss contingencies. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14326-108349 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 25 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6395460&loc=d3e13647-108346 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 30 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13207-110859 + Details
Name: | us-gaap_AccrualForEnvironmentalLossContingencies
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount awarded to other party in judgment or settlement of litigation. + References No definition available. + Details
Name: | us-gaap_LitigationSettlementAmountAwardedToOtherParty
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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: | us-gaap_ProductLiabilityContingencyLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=fstr_UprrMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_MajorCustomersAxis=fstr_UprrMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |