Schedule H, Line 4i - Schedule of Assets (Held at End of Year) (Details) - EBP 003
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12 Months Ended |
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Dec. 31, 2025
USD ($)
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Entity Tax Identification Number |
91-0462470
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| EBP, Plan Number |
003
|
| Notes receivable from participants |
$ 8,209,697
|
| Total assets held for investment purposes |
963,468,337
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| Investment, Identifier [Axis]: Avista Corporation Company Stock Fund |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Current Value |
$ 19,092,877
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| EBP, Investment, Issuer Name [Extensible Enumeration] |
Avista Corporation [Member]
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
us-gaap:CommonStockMember
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| EBP, Asset Held for Investment, Party-in-Interest [true false] |
true
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| Investment, Identifier [Axis]: Baird Core Plus Bond Fund Instl Class Registered Investment Company |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Current Value |
$ 14,139,290
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| EBP, Investment, Issuer Name [Extensible Enumeration] |
Baird Core Plus Bond Fund Instl Class [Member]
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
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| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| Investment, Identifier [Axis]: MFS Growth Fund Class R6 Registered Investment Company |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Current Value |
$ 44,634,607
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| EBP, Investment, Issuer Name [Extensible Enumeration] |
MFS Growth Fund Class R6 [Member]
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
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| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| Investment, Identifier [Axis]: Self-Directed Brokerage Fund Self-Directed Brokerage Fund |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Current Value |
$ 17,395,322
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| EBP, Investment, Issuer Name [Extensible Enumeration] |
Self-Directed Brokerage Fund [Member]
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
EBP, Self-Directed Brokerage Account [Member]
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| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| Investment, Identifier [Axis]: T. Rowe Price Inst'l Large Cap Value Fd C Registered Investment Company |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Current Value |
$ 19,010,651
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| EBP, Investment, Issuer Name [Extensible Enumeration] |
T. Rowe Price Inst'l Large Cap Value Fd C [Member]
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
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| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| Investment, Identifier [Axis]: T. Rowe Price QM US Sm-Cap Grwth Eqty Fd I Registered Investment Company |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Current Value |
$ 4,896,185
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| EBP, Investment, Issuer Name [Extensible Enumeration] |
T. Rowe Price QM US Sm-Cap Grwth Eqty Fd I [Member]
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
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| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| Investment, Identifier [Axis]: Total Mutual Funds |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Current Value |
$ 885,418,068
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
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| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| Investment, Identifier [Axis]: Transamerica International Equity R6 Registered Investment Company |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Current Value |
$ 6,922,085
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| EBP, Investment, Issuer Name [Extensible Enumeration] |
Transamerica International Equity R6 [Member]
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
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| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| Investment, Identifier [Axis]: Vanguard Federal Money Market Fund Registered Investment Company |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Current Value |
$ 15,642,885
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| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Federal Money Market Fund [Member]
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
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| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| Investment, Identifier [Axis]: Vanguard Infla-Prot Securities Registered Investment Company |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Current Value |
$ 7,443,506
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| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Infla-Prot Securities [Member]
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
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| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| Investment, Identifier [Axis]: Vanguard Institutional Index Fund Registered Investment Company |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Current Value |
$ 200,479,375
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| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Institutional Index Fund [Member]
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
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| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| Investment, Identifier [Axis]: Vanguard Intl Growth Fund Admiral Shares Registered Investment Company |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Current Value |
$ 8,155,840
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| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Intl Growth Fund Admiral Shares [Member]
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
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| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| Investment, Identifier [Axis]: Vanguard Mid-Cap Index Fund Instl Shares Registered Investment Company |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Current Value |
$ 46,390,131
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| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Mid-Cap Index Fund Instl Shares [Member]
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
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| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| Investment, Identifier [Axis]: Vanguard Retirement Savings Trust III Collective Trust |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Current Value |
$ 33,352,373
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| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Retirement Savings Trust III [Member]
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Common Collective Trust [Member]
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| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| Investment, Identifier [Axis]: Vanguard Sm-Cap Growth Index Registered Investment Company |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Current Value |
$ 29,306,757
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| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Sm-Cap Growth Index [Member]
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
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| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| Investment, Identifier [Axis]: Vanguard Sm-Cap Value Index Registered Investment Company |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Current Value |
$ 14,328,793
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| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Sm-Cap Value Index [Member]
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
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| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| Investment, Identifier [Axis]: Vanguard Target Ret 2020 Trust II Registered Investment Company |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Current Value |
$ 4,708,971
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| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Ret 2020 Trust II [Member]
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
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| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| Investment, Identifier [Axis]: Vanguard Target Ret 2025 Trust II Registered Investment Company |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Current Value |
$ 10,547,111
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| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Ret 2025 Trust II [Member]
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
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| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| Investment, Identifier [Axis]: Vanguard Target Ret 2030 Trust II Registered Investment Company |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Current Value |
$ 15,707,910
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| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Ret 2030 Trust II [Member]
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
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| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| Investment, Identifier [Axis]: Vanguard Target Ret 2035 Trust II Registered Investment Company |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Current Value |
$ 12,369,732
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| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Ret 2035 Trust II [Member]
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
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| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| Investment, Identifier [Axis]: Vanguard Target Ret 2040 Trust II Registered Investment Company |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
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| Current Value |
$ 15,477,161
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| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Ret 2040 Trust II [Member]
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| Investment, Identifier [Axis]: Vanguard Target Ret 2045 Trust II Registered Investment Company |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| Current Value |
$ 22,906,814
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| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Ret 2045 Trust II [Member]
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| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
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| Investment, Identifier [Axis]: Vanguard Target Ret 2050 Trust II Registered Investment Company |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| Current Value |
$ 29,462,450
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Ret 2050 Trust II [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| Investment, Identifier [Axis]: Vanguard Target Ret 2055 Trust II Registered Investment Company |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| Current Value |
$ 24,697,621
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Ret 2055 Trust II [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| Investment, Identifier [Axis]: Vanguard Target Ret 2060 Trust II Registered Investment Company |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| Current Value |
$ 16,911,710
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Ret 2060 Trust II [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| Investment, Identifier [Axis]: Vanguard Target Ret 2065 Trust II Registered Investment Company |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| Current Value |
$ 3,854,155
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Ret 2065 Trust II [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| Investment, Identifier [Axis]: Vanguard Target Ret 2070 Trust II Registered Investment Company |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| Current Value |
$ 863,002
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Ret 2070 Trust II [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| Investment, Identifier [Axis]: Vanguard Target Ret Income & Grwoth Trust II Registered Investment Company |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| Current Value |
$ 296,440
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Ret Income & Growth Trust II [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| Investment, Identifier [Axis]: Vanguard Target Ret Income Trust II Registered Investment Company |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| Current Value |
$ 4,670,173
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Target Ret Income Trust II [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| Investment, Identifier [Axis]: Vanguard Total Bd Mkt Indx Inv Registered Investment Company |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| Current Value |
$ 64,838,493
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Total Bd Mkt Indx Inv [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| Investment, Identifier [Axis]: Vanguard Total Int'l Stock Idx Registered Investment Company |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| Current Value |
$ 82,961,262
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Total Int'l Stock Idx [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| Investment, Identifier [Axis]: Vanguard Wellington Fund Admiral Shares Registered Investment Company |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| Current Value |
$ 161,768,149
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Vanguard Wellington Fund Admiral Shares [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
|
| EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Participation Status [Extensible Enumeration] |
us-gaap-ebp:EmployeeBenefitPlanParticipantDirectedMember
|
| Investment, Identifier [Axis]: Victory Sycamore Sm Co Opportunity Fd R6 Registered Investment Company |
|
| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| Current Value |
$ 2,026,809
|
| EBP, Investment, Issuer Name [Extensible Enumeration] |
Victory Sycamore Sm Co Opportunity Fd R6 [Member]
|
| EBP, Investment, Current Value, Type [Extensible Enumeration] |
Mutual Fund [Member]
|
| Minimum |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| Employee benefit plan, asset held for investment, participant loan, interest rate |
4.25%
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| Maximum |
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| EBP, Schedule of Asset Held for Investment [Line Items] |
|
| Employee benefit plan, asset held for investment, participant loan, interest rate |
9.50%
|