v3.26.1
Schedule H, Line 4i – Schedule of Assets (Held At End of Year) (Details) - EBP 005
12 Months Ended
Dec. 31, 2025
USD ($)
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: $ 888,956,383
Notes receivable from participants 7,090,775
Investments, fair value $ 896,047,158
Entity tax identification number 85-0468296
Plan number 005
Minimum  
EBP, Schedule of Asset Held for Investment [Line Items]  
Outstanding loans interest rates 5.75%
Maximum  
EBP, Schedule of Asset Held for Investment [Line Items]  
Outstanding loans interest rates 11.00%
Investment, Identifier [Axis]: Acadian All Country World ex US Equity | Collective Investment Trust  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: $ 60,665,284
Investment, Identifier [Axis]: Allspring Discovery Small/Mid-Cap Growth CIT; Class E1 | Collective Investment Trust  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 11,392,299
Investment, Identifier [Axis]: JPMCB Large Cap Growth Fund; CF-2 Class | Collective Investment Trust  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 82,625,315
Investment, Identifier [Axis]: Met West Total Ret Bond P | Registered Investment Company  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 56,493,552
Investment, Identifier [Axis]: PIMCO Inflation Response Multi-Asset Fund; Inst. Class | Registered Investment Company  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 848,205
Investment, Identifier [Axis]: TXNM Energy, Inc. Common Stock Fund | Company stock  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 6,990,503
Investment, Identifier [Axis]: Vanguard Index Fund | Registered Investment Company  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 150,869,901
Investment, Identifier [Axis]: Vanguard Institutional Target Retirement 2020 | Collective Investment Trust  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 11,605,047
Investment, Identifier [Axis]: Vanguard Institutional Target Retirement 2025 | Collective Investment Trust  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 42,682,421
Investment, Identifier [Axis]: Vanguard Institutional Target Retirement 2030 | Collective Investment Trust  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 20,165,462
Investment, Identifier [Axis]: Vanguard Institutional Target Retirement 2035 | Collective Investment Trust  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 53,316,802
Investment, Identifier [Axis]: Vanguard Institutional Target Retirement 2040 | Collective Investment Trust  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 18,562,789
Investment, Identifier [Axis]: Vanguard Institutional Target Retirement 2045 | Collective Investment Trust  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 56,684,210
Investment, Identifier [Axis]: Vanguard Institutional Target Retirement 2050 | Collective Investment Trust  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 20,465,469
Investment, Identifier [Axis]: Vanguard Institutional Target Retirement 2055 | Collective Investment Trust  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 14,778,077
Investment, Identifier [Axis]: Vanguard Institutional Target Retirement 2060 | Collective Investment Trust  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 10,198,422
Investment, Identifier [Axis]: Vanguard Institutional Target Retirement 2065 | Collective Investment Trust  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 3,637,149
Investment, Identifier [Axis]: Vanguard Institutional Target Retirement 2070 | Collective Investment Trust  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 654,975
Investment, Identifier [Axis]: Vanguard Institutional Target Retirement Income | Collective Investment Trust  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 23,893,582
Investment, Identifier [Axis]: Vanguard Prime Money Market Fund | Registered Investment Company  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 38,835,230
Investment, Identifier [Axis]: Vanguard Retirement Savings Trust III | Collective Investment Trust  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 38,626,876
Investment, Identifier [Axis]: Vanguard Wellington Fund | Registered Investment Company  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 109,716,721
Investment, Identifier [Axis]: Vanguard Windsor II Fund | Registered Investment Company  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: 49,621,191
Investment, Identifier [Axis]: Victory Integrity Small/Mid-Cap Value Fund; Y | Registered Investment Company  
EBP, Schedule of Asset Held for Investment [Line Items]  
Investments at fair value: $ 5,626,901