1001 - Document - Cover link:presentationLink link:definitionLink link:calculationLink 1002 - Statement - Statements of Net Assets Available for Benefits link:presentationLink link:definitionLink link:calculationLink 1003 - Statement - Statement of Changes in Net Assets Available for Benefits link:presentationLink link:definitionLink link:calculationLink 1004 - Disclosure - Description of the Plan link:presentationLink link:definitionLink link:calculationLink 1005 - Disclosure - Summary of Significant Accounting Policies link:presentationLink link:definitionLink link:calculationLink 1006 - Disclosure - Fair Value Measurements link:presentationLink link:definitionLink link:calculationLink 1007 - Disclosure - Forfeitures link:presentationLink link:definitionLink link:calculationLink 1008 - Disclosure - Administrative Expenses link:presentationLink link:definitionLink link:calculationLink 1009 - Disclosure - Federal Income Tax Status link:presentationLink link:definitionLink link:calculationLink 1010 - Disclosure - Plan Termination link:presentationLink link:definitionLink link:calculationLink 1011 - Disclosure - Party-In-Interest link:presentationLink link:definitionLink link:calculationLink 1012 - Disclosure - Reconciliation of Financial Statements to Form 5500 link:presentationLink link:definitionLink link:calculationLink 1013 - Disclosure - Risk and Uncertainties link:presentationLink link:definitionLink link:calculationLink 1014 - Disclosure - Subsequent Events link:presentationLink link:definitionLink link:calculationLink 1015 - Disclosure - Schedule H, Line 4i - Schedule of Assets (Held At End of Year) link:presentationLink link:definitionLink link:calculationLink 1016 - Disclosure - Summary of Significant Accounting Policies (Policies) link:presentationLink link:definitionLink link:calculationLink 1017 - Disclosure - Fair Value Measurements (Tables) link:presentationLink link:definitionLink link:calculationLink 1018 - Disclosure - Reconciliation of Financial Statements to Form 5500 (Tables) link:presentationLink link:definitionLink link:calculationLink 1019 - Disclosure - Description of the Plan - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 1020 - Schedule - Fair Value Measurements - Summary of Fair Value Hierarchy (Detail) link:presentationLink link:definitionLink link:calculationLink 1021 - Disclosure - Forfeitures - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 1022 - Disclosure - Federal Income Tax Status - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 1023 - Disclosure - Plan Termination - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 1024 - Disclosure - Party-In-Interest - Additional Information (Detail) link:presentationLink link:definitionLink link:calculationLink 1025 - Disclosure - Reconciliation of Financial Statements to Form 5500 - Summary Of a Reconciliation Of Net Assets Available For Benefits (Detail) link:presentationLink link:definitionLink link:calculationLink 1026 - Disclosure - Schedule H, Line 4i- Schedule of Assets (Held at End of Year) (Detail) link:presentationLink link:definitionLink link:calculationLink 1027 - Disclosure - Description of the Plan - Additional Information (Detail) Alternate link:presentationLink link:definitionLink link:calculationLink 1028 - Disclosure - Schedule H, Line 4i- Schedule of Assets (Held at End of Year) (Detail) Alternate link:presentationLink link:definitionLink link:calculationLink Cover [Abstract] Document Information [Table] Legal Entity [Axis] Entity [Domain] EBP 022 [Member] Document Information [Line Items] Document Type Amendment Flag Document Period End Date Document Fiscal Year Focus Document Fiscal Period Focus Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date EBP, Statement of Net Asset Available for Benefit [Abstract] EBP, Statement of Net Asset Available for Benefit [Table] EBP, Statement of Net Asset Available for Benefit [Line Items] EBP, Asset [Abstract] Assets: EBP, Investment, Excluding Plan Interest in Master Trust, Fair Value Investments, at fair value EBP, Investment, excluding plan Interest in master trust, fair value EBP, Receivable [Abstract] Receivables: EBP, Employer Contribution, Receivable Employer contribution receivable EBP, Note Receivable from Participant Notes receivable from participants EBP, Receivable Total receivables EBP, Net Asset Available for Benefit Net assets available for benefits Beginning of year End of year Net assets available for benefits per the financial statements EBP, Statement of Change in Net Asset Available for Benefit [Abstract] EBP, Statement of Change in Net Asset Available for Benefit [Table] EBP, Statement of Change in Net Asset Available for Benefit [Line Items] EBP, Change in Net Asset Available for Benefit, Increase [Abstract] Additions EBP, Change in Net Asset Available for Benefit, Increase from Interest and Dividend Income on Investment Interest and dividend income EBP, Change in Net Asset Available for Benefit, Increase from Interest Income on Note Receivable from Participant Interest on notes receivable from participants EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Gain (Loss) on Investment Net appreciation in fair value of investments EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment Subtotal of additions EBP, Change in Net Asset Available for Benefit, Increase from Contribution [Abstract] Contributions EBP, Change in Net Asset Available for Benefit, Increase from Employer Contribution, Cash and Noncash Employer contributions EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Excluding Rollover Participant contributions EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Rollover Rollovers EBP, Change in Net Asset Available for Benefit, Increase from Contribution Subtotal of contributions EBP, Change in Net Asset Available for Benefit, Increase Total additions EBP, Change in Net Asset Available for Benefit, Decrease [Abstract] Deductions EBP, Change in Net Asset Available for Benefit, Decrease from Payment to Participant Benefits paid to participants EBP, Change in Net Asset Available for Benefit, Decrease from Administrative Expense Administrative expenses EBP, Change in Net Asset Available for Benefit, Decrease Subtotal of Deductions EBP, Change in Net Asset Available for Benefit, Increase (Decrease) Total Net increase in net assets Net increase in net assets available for benefits per the financial statements EBP, Description of Plan and Accounting Change [Abstract] EBP, Description of Plan [Table] EBP, Description of Plan [Line Items] EBP, Description of Plan [Text Block] Description of the Plan EBP, Summary of Accounting Policy [Text Block] Summary of Significant Accounting Policies EBP, Investment, Fair Value and NAV [Abstract] EBP, Investment, Fair Value and NAV [Table] EBP, Investment, Fair Value and NAV [Line Items] EBP, Investment, Fair Value and NAV [Text Block] Fair Value Measurements EBP, Forfeited Nonvested Account [Abstract] Employee Benefit Plan Forfeited Nonvested Account [Table] Employee Benefit Plan Forfeited Nonvested Account [Line Items] Employee Benefit Plan, Forfeitures [Text Block] Forfeitures Employee benefit plan, forfeitures. Employee Benefit Plan, Administrative Expenses [Abstract] Employee Benefit Plan, Administrative Expenses [Table] Employee Benefit Plan, Administrative Expenses [Line Items] EBP, Administrative Expenses Text Block Administrative Expenses EBP, Administrative Expenses Text Block. EBP, Tax Status [Abstract] EBP, Tax Status [Table] EBP, Tax Status [Line Items] EBP, Tax Status [Text Block] Federal Income Tax Status EBP, Plan Termination [Text Block] Plan Termination EBP, Related Party and Party-in-Interest Transactions [Abstract] EBP, Related Party and Party-in-Interest Transactions [Table] EBP, Related Party and Party-in-Interest Transactions [Line Items] EBP, Related Party and Party-in-Interest Transactions [Text Block] Party-In-Interest EBP, Reconciliation of Financial Statement to Form 5500 [Abstract] EBP, Reconciliation of Financial Statement to Form 5500 [Table] EBP, Reconciliation of Financial Statement to Form 5500 [Line Items] EBP, Reconciliation of Financial Statement to Form 5500 [Text Block] Reconciliation of Financial Statements to Form 5500 EBP, Risk and Uncertainty [Abstract] EBP, Risk and Uncertainty [Table] EBP, Risk and Uncertainty [Line Items] EBP, Risk and Uncertainty [Text Block] Risk and Uncertainties EBP, Subsequent Event [Abstract] EBP, Subsequent Event [Table] EBP, Subsequent Event [Line Items] EBP, Subsequent Event [Text Block] Subsequent Events EBP, Schedule of Asset Held for Investment [Abstract] EBP, Schedule of Asset Held for Investment [Table] EBP, Schedule of Asset Held for Investment [Line Items] EBP, Schedule of Asset Held for Investment [Table Text Block] Schedule H, Line 4i – Schedule of Assets (Held At End of Year) EBP, Basis of Accounting [Policy Text Block] Basis of Accounting EBP, Use of Estimate [Policy Text Block] Use of Estimates Employee Benefit Plan Fair Value Measurement [Policy Text Block] Fair Value Measurements Employee benefit plan fair value measurement. EBP, Investment [Policy Text Block] Investment Valuation EmployeeBenefitPlanIncomeRecognition [Policy Text Block] Income Recognition Employee benefit plan income recognition policy. EBP, Note Receivable from Participant [Policy Text Block] Notes Receivable from Participants EBP, Contribution [Policy Text Block] Contributions EBP, Payment to Participant [Policy Text Block] Benefit Payments EBP, Investment, Fair Value and NAV [Table Text Block] Summary of Fair Value Hierarchy EBP, Reconciliation of Financial Statement to Form 5500 [Table Text Block] Summary of a reconciliation of net assets available for benefits EBP, Participant Age, Catch-Up Contribution, Threshold Participant age, catch-up contribution, Threshold EBP, participant age, catch-up contribution, threshold EBP, Participant Contribution, Pretax, Maximum Annual Compensation to Total Compensation, Percentage Participant contribution, Percentage EBP, Participant Contribution, Plan Opting Decision Making, Number Of days, Maximum Participant contribution, plan opting decision making, number of days, maximum EBP, participant contribution, plan opting decision making, number of days, maximum. EBP, Participant Contribution, Automatic, Deferral Rate Participant contribution, automatic, deferral rate EBP, Annual Increase In Deferral Rate Under Auto-Escalation Annual increase in deferral rate under auto-escalation EBP, annual increase in deferral rate under auto-escalation. Employee Benefit Plan Participant Contribution Maximum Deferral Rate Employee benefit plan participant contribution maximum deferral rate Employee benefit plan participant contribution maximum deferral rate. EBP, Employer Contribution, Matching Percentage Employer contribution, matching percentage EBP, Employer Contribution, Participant Compensation Matched, Percentage Employer contribution, participant compensation matched, percentage Employee Benefit Plan Employer Contribution True Up Matching Percentage Description Employee benefit plan employer contribution true up matching percentage description Employee benefit plan employer contribution true-up matching percentage description. Employee Benefit Plan Company Retirement Contribution (As A Percentage Of Eligible Earnings) Employee benefit plan company retirement contribution (As A percentage of eligible earnings) Employee benefit plan company retirement contribution (as a percentage of eligible earnings). Employee Benefit Plan, Participant Account, Vesting Percentage Employee benefit plan, participant account, vesting percentage Employee benefit plan, participant account, vesting percentage. Employee Benefit Plan, Company Retirement Contribution, Completion Of service, Threshold Employee benefit plan, company retirement contribution, completion of service, Threshold Employee benefit plan, company retirement contribution, completion of service, threshold. Employee Benefit Plan, Plan Termination, Participant Account, Vesting Percentage Employee benefit plan, plan termination, participant account, vesting percentage Employee benefit plan, plan termination, participant account, vesting percentage Employee benefit plan, plan termination, participant account, vesting percentage. Employee Benefit Plan, Vested Account Payable, Participant Age, Threshold Employee benefit plan, vested account payable, participant age, threshold Employee benefit plan, vested account payable, participant age, threshold. Employee Benefit Plan Lump Sum Payment Account Balance Threshold Employee benefit plan lump sum payment account balance threshold Employee benefit plan lump sum payment account balance threshold. Employee Benefit Plan Lump Sum Payment Percentage Employee benefit plan lump sum payment percentage Employee benefit plan lump sum payment perecntage. Employee Benefit Plan Lump Sum Payment Threshold Employee benefit plan lump sum payment threshold Employee benefit plan lump sum payment threshold. Employee Benefit Plan Note Receivable From Participant Account Maximum Borrowing Amount Description Employee benefit plan note receivable from participant account maximum borrowing amount description Employee benefit plan note receivable from participant account maximum borrowing amount description. Employee Benefit Plan Loan Repayment Period Maximum Employee benefit plan loan repayment period maximum Employee benefit plan loan repayment period maximum. Employee Benefit Plan Note Receivable From Participant Account Borrowing Standardize Percentage Employee benefit plan note receivable from participant account borrowing standardize percentage Employee benefit plan note receivable from participant account borrowing standardize percentage. EBP, Asset Held for Investment, Participant Loan, Interest Rate EBP, asset held for investment, participant loan, interest rate EBP, vested amount of direct rollover if no election EBP, vested amount of direct rollover if no election. Statistical Measurement [Axis] Statistical Measurement [Domain] Maximum [Member] Minimum [Member] Investment, Identifier [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Inputs, Level 1, Level 2, and Level 3 [Member] Fair Value Measured at Net Asset Value Per Share [Member] Investment Type [Axis] Investments [Domain] Mutual Fund [Member] Common Stock [Member] Common Collective Trust [Member] EBP, Forfeited Nonvested Account, Decrease from Employer Contribution Participant forfeitures toward the payment of the Company contribution EBP, Forfeited Nonvested Account EBP, forfeited nonvested account EBP, Tax Determination Letter, Date EBP, tax determination letter, date EBP, Employer, Common Stock [Member] EBP, Change in Net Asset Available for Benefit, Increase from Dividend Income on Investment EBP, change in net asset available for benefit, increase from dividend income on investment EBP, Reconciliation to Form 5500, Net Asset Available for Benefit, Deemed Distribution Deemed distributions -reduction of loans EBP, Form 5500 Caption, Net Assets Net assets available for benefits per Form 5500 EBP, Reconciliation to Form 5500, Payment to Participant, Increase (Decrease) from Deemed Distribution Deemed distributions -reduction of loans EBP, Form 5500 Caption, Benefit Payment and Payments to Provide Benefits Net increase in assets available for benefits per Form 5500 Investment, Issuer Name [Axis] Investment, Issuer Name [Domain] Entity Tax Identification Number EBP, Plan Number EBP, Investment, Issuer Name [Extensible Enumeration] EBP, Investment, Current Value, Type [Extensible Enumeration] EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] EBP, Asset Held for Investment EBP, Asset Held for Investment, Plan Interest in Master Trust, Current Value EBP, Asset Held for Investment, Party-in-Interest [true false] EBP, Participant-Directed and Nonparticipant-Directed Status [Axis] EBP, Participant-Directed and Nonparticipant-Directed Status [Domain] EBP, Participant-Directed [Member] Cabot Corporation [Member] MFS Growth Equity Fund Class S [Member] Vanguard Explorer Fund [Member] Vanguard Extended Market Index Fund [Member] Vanguard Federal Money Market Fund [Member] Vanguard InflationProtected Securities Fund Adm Shares [Member] Vanguard Institutional Index Fund [Member] Vanguard International Growth Fund [Member] Vanguard International Value Fund [Member] Vanguard Retirement Savings Trust III [Member] Vanguard Shortterm Federal Fund [Member] Vanguard Target Retirement 2020 Trust II [Member] Vanguard Target Retirement 2025 Trust II [Member] Vanguard Target Retirement 2030 Trust II [Member] Vanguard Target Retirement 2035 Trust II [Member] Vanguard Target Retirement 2040 Trust II [Member] Vanguard Target Retirement 2045 Trust II [Member] Vanguard Target Retirement 2050 Trust II [Member] Vanguard Target Retirement 2055 Trust II [Member] Vanguard Target Retirement 2060 Trust II [Member] Vanguard Target Retirement 2065 Trust II [Member] Vanguard Target Retirement 2070 Trust II [Member] Vanguard Target Retirement Income and Growth Trust II [Member]