XML 256 R46.htm IDEA: XBRL DOCUMENT
v3.24.2

Commitments and Contingencies - Additional Information (Details) |  |  |  |  |  |  |  | 1 Months Ended | 4 Months Ended | 5 Months Ended | 6 Months Ended | 7 Months Ended | 12 Months Ended | 36 Months Ended | 180 Months Ended |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Dec. 20, 2021 USD ($) Plaintiff | Apr. 25, 2017 USD ($) | Feb. 24, 2017 Plaintiff | Sep. 17, 2014 Plaintiff case | Nov. 30, 2012 Plaintiff | Apr. 29, 2011 USD ($) | Apr. 22, 2011 USD ($) Plaintiff | Mar. 31, 2018 USD ($) Plaintiff | Nov. 30, 2017 plaintiff | Aug. 31, 2017 Plaintiff | May 31, 2016 Plaintiff | Nov. 30, 2015 Plaintiff | Jan. 31, 2015 case | Jan. 31, 2015 Plaintiff | Jan. 31, 2015 Case | Dec. 31, 2014 Plaintiff | Mar. 31, 2014 Plaintiff | Dec. 31, 2012 Plaintiff | Nov. 30, 2011 Plaintiff | Jul. 31, 2013 Plaintiff | Dec. 31, 2015 Plaintiff case | Oct. 31, 2016 plaintiff Case | Oct. 31, 2012 Plaintiff Case case | Dec. 31, 2017 USD ($) Plaintiff plaintiff | Dec. 31, 2010 USD ($) case plaintiff | Dec. 31, 2009 USD ($) Plaintiff | Dec. 31, 2008 Plaintiff | Dec. 31, 2009 case plaintiff | Dec. 31, 2013 case plaintiff | Jun. 30, 2024 USD ($) | Jan. 04, 2011 Plaintiff
Commitments Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding letters of credit and bonds | $ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 25,700,000 |
Number of plaintiffs (plaintiff) |  |  |  |  |  |  |  | 921 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Gain contingency, unrecorded amount | $ |  | $ 100,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Settlement offer per eligible plaintiff who has already filed a lawsuit | $ |  |  |  |  |  |  |  | $ 700 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Settlement offer per eligible plaintiff who has not already filed a lawsuit | $ |  |  |  |  |  |  |  | $ 300 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of firefighters considered as part of the settlement |  |  |  |  |  |  |  | 2,160 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of plaintiffs cases dismissed (plaintiff) |  |  |  |  | 2 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Circuit Court Of Cook County |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of plaintiffs (plaintiff) | plaintiff |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2,816 |  |
Number of cases of plaintiff's claims (case) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 27 |  |  |  |
Number of new claims filed (case) | case |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 40 |  |
Court of Common Pleas, Philadelphia County |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of cases of plaintiff's claims (case) | case |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2 |  |  | 3 |  |  |
Number of claims dismissed (case) | case |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1 |  |  |
Damages maximum amount | $ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 100,000 |  |  |  |  |  |
Number of claimants settled (plaintiff) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1,125
Settlement Agreement |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of plaintiffs (plaintiff) |  |  |  |  |  |  | 1,069 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Claims settled amount | $ |  |  |  |  |  | $ 3,800,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Litigation settlement | $ |  |  |  |  |  |  | $ 3,600,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Settlement Candidates |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of plaintiffs (plaintiff) | 462 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1,090 |  |  |  |  |  |  |
Chicago Firefighter Plaintiffs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of plaintiffs (plaintiff) |  |  | 1,770 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Responsive Settlement Candidates |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of plaintiffs (plaintiff) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 717 |  |  |  |  |  |  |
Lackawanna Firefighter Plaintiffs | Lackawanna County Pennsylvania [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of plaintiffs (plaintiff) |  |  |  |  |  |  |  |  |  | 70 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of new claims filed (case) |  |  |  |  |  |  |  |  |  | 5 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Outside Chicago Firefighter Plaintiffs | CookCountyandDupageCounty |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Litigation settlement | $ | $ 200,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Chicago Firefighter Plaintiffs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of plaintiffs (plaintiff) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3 | 8 |  |  |  |  |  |  |  |  |  |  |  |
Chicago Firefighter Plaintiffs | Circuit Court Of Cook County |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of plaintiffs (plaintiff) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 9 |  |  |  |  |
Litigation settlement | $ |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 700 |  | $ 400,000 |  |  |  |  |
Philadelphia Firefighter Plaintiffs | Court of Common Pleas, Philadelphia County |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of plaintiffs (plaintiff) |  |  |  |  |  |  |  |  | 1 |  |  |  | 7 | 70 |  | 3 |  |  |  |  |  |  | 20 | 155 | 9 |  |  | 71 |  |  |
Number of claims dismissed (case) | case |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5 |  |  |  |  |  |  |  |
Number of new claims filed (case) |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2 |  |  |  |  |  | 9 |  | 20 |  |  |  |  |  |  |  |
District of Columbia Firefighter Plaintiffs | Federal Court, Eastern District of Pennsylvania |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of plaintiffs (plaintiff) |  |  |  |  |  |  |  |  |  |  |  |  |  | 11 |  |  |  |  |  |  | 193 |  |  |  |  |  |  |  |  |  |
Number of new claims filed (case) | case |  |  |  |  |  |  |  |  |  |  |  |  | 1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Pittsburgh Firefighter Plaintiffs | Allegheny County, Pennsylvania |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of plaintiffs (plaintiff) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 247 |  |  |  |  |  |  |  |  |  |  |
Number of claims dismissed (case) |  |  |  |  |  |  |  |  |  |  | 55 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of new claims filed (case) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 19 |  |  |  |  |  |  |  |  |  |  |
Buffalo Firefighter Plaintiffs | Supreme Court of State of New York Erie County |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of plaintiffs (plaintiff) |  |  |  | 193 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of new claims filed (case) | case |  |  |  | 20 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
New York City Firefighter Plaintiffs | Lackawanna County Pennsylvania [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of plaintiffs (plaintiff) |  |  |  |  |  |  |  |  |  | 1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
New Jersey Firefighter Plaintiffs | Superior Court of New Jersey, Union County |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of plaintiffs (plaintiff) |  |  |  |  |  |  |  |  |  |  |  | 34 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Massachusetts Firefighter Plaintiffs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of plaintiffs (plaintiff) | plaintiff |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 194 |  |  |  |  |  |  |  |  |
Number of new claims filed (case) | Case |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 9 |  |  |  |  |  |  |  |  |
Erie County Firefighter Plaintiffs | Court of Common Pleas, Philadelphia County |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of plaintiffs (plaintiff) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 61 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Florida Firefighters Plaintiffs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Commitments Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of plaintiffs (plaintiff) | plaintiff |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1,084 |  |  |  |  |  |  |  |  |

X
- Definition Commitments Disclosure [Line Items] + References No definition available. + Details
Name: | fss_CommitmentsDisclosureLineItems
Namespace Prefix: | fss_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Loss contingency claims settled amount. + References No definition available. + Details
Name: | fss_LossContingencyClaimsSettledAmount
Namespace Prefix: | fss_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Loss contingency number of plaintiffs, dismissed. + References No definition available. + Details
Name: | fss_LossContingencyNumberOfPlaintiffsDismissed
Namespace Prefix: | fss_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of firefighters whose claims may be considered as part of this settlement offer. + References No definition available. + Details
Name: | fss_NumberOfFirefightersConsideredAsPartOfTheSettlement
Namespace Prefix: | fss_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Settlement offer amount to each firefighter who has already filed a lawsuit and is eligible to be part of the settlement. + References No definition available. + Details
Name: | fss_SettlementOfferPerEligiblePlaintiffWhoHasAlreadyFiledALawsuit
Namespace Prefix: | fss_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Settlement offer amount to each firefighter who has not filed a case and is eligible to be part of the settlement. + References No definition available. + Details
Name: | fss_SettlementOfferPerEligiblePlaintiffWhoHasNotAlreadyFiledALawsuit
Namespace Prefix: | fss_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The total amount of the contingent obligation under letters of credit outstanding as of the reporting date. + References No definition available. + Details
Name: | us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount awarded from other party in judgment or settlement of litigation. + References No definition available. + Details
Name: | us-gaap_LitigationSettlementAmountAwardedFromOtherParty
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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 Number of claims dismissed. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483076/450-20-50-4 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483076/450-20-50-9 + Details
Name: | us-gaap_LossContingencyClaimsDismissedNumber
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of claims settled and dismissed during the period. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483076/450-20-50-4 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483076/450-20-50-9 + Details
Name: | us-gaap_LossContingencyClaimsSettledAndDismissedNumber
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition The value (monetary amount) of the award the plaintiff seeks in the legal matter. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483076/450-20-50-1 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483076/450-20-50-4 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483076/450-20-50-9 + Details
Name: | us-gaap_LossContingencyDamagesSoughtValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The total number of new claims filed pertaining to a loss contingency during the period. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483076/450-20-50-4 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483076/450-20-50-9 + Details
Name: | us-gaap_LossContingencyNewClaimsFiledNumber
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of plaintiffs that have filed claims pertaining to a loss contingency. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483076/450-20-50-4 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483076/450-20-50-9 + Details
Name: | us-gaap_LossContingencyNumberOfPlaintiffs
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of pending claims pertaining to a loss contingency. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483076/450-20-50-4 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483076/450-20-50-9 + Details
Name: | us-gaap_LossContingencyPendingClaimsNumber
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | srt_LitigationCaseAxis=fss_CircuitCourtOfCookCountyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_LitigationCaseAxis=fss_CourtOfCommonPleasPhiladelphiaCountyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_LitigationCaseAxis=fss_SettlementAgreementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | fss_PlaintiffsAxis=fss_SettlementCandidatesDomain
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | fss_PlaintiffsAxis=fss_ChicagoFirefighterPlaintiffsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | fss_PlaintiffsAxis=fss_ResponsiveSettlementCandidatesDomain
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=fss_LackawannaFirefighterPlaintiffsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_LitigationCaseAxis=fss_LackawannaCountyPennsylvaniaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=fss_OutsideChicagoFirefighterPlaintiffsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_LitigationCaseAxis=fss_CookCountyandDupageCountyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=fss_ChicagoFirefighterPlaintiffsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=fss_PhiladelphiaFirefighterPlaintiffsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=fss_DistrictofColumbiaFirefighterPlaintiffsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_LitigationCaseAxis=fss_FederalCourtEasternDistrictofPennsylvaniaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=fss_PittsburghFirefighterPlaintiffsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_LitigationCaseAxis=fss_AlleghenyCountyPennsylvaniaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=fss_BuffaloFirefighterPlaintiffsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_LitigationCaseAxis=fss_SupremeCourtofStateofNewYorkErieCountyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=fss_NewYorkCityFirefighterPlaintiffsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=fss_NewJerseyFirefighterPlaintiffsMemberDomain
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_LitigationCaseAxis=fss_SuperiorCourtofNewJerseyUnionCountyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=fss_MassachusettsFirefighterPlaintiffsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=fss_ErieCountyFirefighterPlaintiffsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=fss_FloridaFirefightersPlaintiffsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |