Long-Duration Insurance Contracts - Account Balances by Guaranteed Minimum Interest Rates (Details) $ in Millions	Sep. 30, 2025 USD ($)	Dec. 31, 2024 USD ($)
Policyholder Account Balance [Line Items]
Policyholders' account balances	$ 5,092.0	$ 5,100.3
Less than 2%
Policyholder Account Balance [Line Items]
Policyholders' account balances	$ 755.8	$ 797.6
Less than 2% \| Maximum
Policyholder Account Balance [Line Items]
Policyholder account balance, guaranteed minimum credit rating	2.00%	2.00%
Equal to 2% but less than 3%
Policyholder Account Balance [Line Items]
Policyholders' account balances	$ 503.4	$ 449.4
Equal to 2% but less than 3% \| Minimum
Policyholder Account Balance [Line Items]
Policyholder account balance, guaranteed minimum credit rating	2.00%	2.00%
Equal to 2% but less than 3% \| Maximum
Policyholder Account Balance [Line Items]
Policyholder account balance, guaranteed minimum credit rating	3.00%	3.00%
Equal to 3% but less than 4%
Policyholder Account Balance [Line Items]
Policyholders' account balances	$ 683.0	$ 653.4
Equal to 3% but less than 4% \| Minimum
Policyholder Account Balance [Line Items]
Policyholder account balance, guaranteed minimum credit rating	3.00%	3.00%
Equal to 3% but less than 4% \| Maximum
Policyholder Account Balance [Line Items]
Policyholder account balance, guaranteed minimum credit rating	4.00%	4.00%
Equal to 4% but less than 5%
Policyholder Account Balance [Line Items]
Policyholders' account balances	$ 2,565.2	$ 2,600.0
Equal to 4% but less than 5% \| Minimum
Policyholder Account Balance [Line Items]
Policyholder account balance, guaranteed minimum credit rating	4.00%	4.00%
Equal to 4% but less than 5% \| Maximum
Policyholder Account Balance [Line Items]
Policyholder account balance, guaranteed minimum credit rating	5.00%	5.00%
5% or higher
Policyholder Account Balance [Line Items]
Policyholders' account balances	$ 79.8	$ 81.8
5% or higher \| Minimum
Policyholder Account Balance [Line Items]
Policyholder account balance, guaranteed minimum credit rating	5.00%	5.00%
Policyholder account balance with a guaranteed minimum crediting rate
Policyholder Account Balance [Line Items]
Policyholders' account balances	$ 4,587.2	$ 4,582.2
At Guaranteed Minimum \| Less than 2%
Policyholder Account Balance [Line Items]
Policyholders' account balances	9.0	15.9
At Guaranteed Minimum \| Equal to 2% but less than 3%
Policyholder Account Balance [Line Items]
Policyholders' account balances	70.4	94.5
At Guaranteed Minimum \| Equal to 3% but less than 4%
Policyholder Account Balance [Line Items]
Policyholders' account balances	571.8	545.6
At Guaranteed Minimum \| Equal to 4% but less than 5%
Policyholder Account Balance [Line Items]
Policyholders' account balances	2,565.2	2,600.0
At Guaranteed Minimum \| 5% or higher
Policyholder Account Balance [Line Items]
Policyholders' account balances	79.8	81.8
At Guaranteed Minimum \| Policyholder account balance with a guaranteed minimum crediting rate
Policyholder Account Balance [Line Items]
Policyholders' account balances	$ 3,296.2	$ 3,337.8
1-50 Basis Points Above \| Minimum
Policyholder Account Balance [Line Items]
Policyholder account balance, above guaranteed minimum crediting rate	0.0001	0.0001
1-50 Basis Points Above \| Maximum
Policyholder Account Balance [Line Items]
Policyholder account balance, above guaranteed minimum crediting rate	0.0050	0.0050
1-50 Basis Points Above \| Less than 2%
Policyholder Account Balance [Line Items]
Policyholders' account balances	$ 10.8	$ 77.3
1-50 Basis Points Above \| Equal to 2% but less than 3%
Policyholder Account Balance [Line Items]
Policyholders' account balances	145.6	122.2
1-50 Basis Points Above \| Equal to 3% but less than 4%
Policyholder Account Balance [Line Items]
Policyholders' account balances	10.0	43.3
1-50 Basis Points Above \| Equal to 4% but less than 5%
Policyholder Account Balance [Line Items]
Policyholders' account balances	0.0	0.0
1-50 Basis Points Above \| 5% or higher
Policyholder Account Balance [Line Items]
Policyholders' account balances	0.0	0.0
1-50 Basis Points Above \| Policyholder account balance with a guaranteed minimum crediting rate
Policyholder Account Balance [Line Items]
Policyholders' account balances	$ 166.4	$ 242.8
51-150 Basis Points Above \| Minimum
Policyholder Account Balance [Line Items]
Policyholder account balance, above guaranteed minimum crediting rate	0.0051	0.0051
51-150 Basis Points Above \| Maximum
Policyholder Account Balance [Line Items]
Policyholder account balance, above guaranteed minimum crediting rate	0.0150	0.0150
51-150 Basis Points Above \| Less than 2%
Policyholder Account Balance [Line Items]
Policyholders' account balances	$ 310.4	$ 400.4
51-150 Basis Points Above \| Equal to 2% but less than 3%
Policyholder Account Balance [Line Items]
Policyholders' account balances	121.0	97.9
51-150 Basis Points Above \| Equal to 3% but less than 4%
Policyholder Account Balance [Line Items]
Policyholders' account balances	22.4	13.3
51-150 Basis Points Above \| Equal to 4% but less than 5%
Policyholder Account Balance [Line Items]
Policyholders' account balances	0.0	0.0
51-150 Basis Points Above \| 5% or higher
Policyholder Account Balance [Line Items]
Policyholders' account balances	0.0	0.0
51-150 Basis Points Above \| Policyholder account balance with a guaranteed minimum crediting rate
Policyholder Account Balance [Line Items]
Policyholders' account balances	$ 453.8	$ 511.6
Greater Than 150 Basis Points Above \| Minimum
Policyholder Account Balance [Line Items]
Policyholder account balance, above guaranteed minimum crediting rate	0.0150	0.0150
Greater Than 150 Basis Points Above \| Less than 2%
Policyholder Account Balance [Line Items]
Policyholders' account balances	$ 425.7	$ 304.0
Greater Than 150 Basis Points Above \| Equal to 2% but less than 3%
Policyholder Account Balance [Line Items]
Policyholders' account balances	166.3	134.8
Greater Than 150 Basis Points Above \| Equal to 3% but less than 4%
Policyholder Account Balance [Line Items]
Policyholders' account balances	78.8	51.2
Greater Than 150 Basis Points Above \| Equal to 4% but less than 5%
Policyholder Account Balance [Line Items]
Policyholders' account balances	0.0	0.0
Greater Than 150 Basis Points Above \| 5% or higher
Policyholder Account Balance [Line Items]
Policyholders' account balances	0.0	0.0
Greater Than 150 Basis Points Above \| Policyholder account balance with a guaranteed minimum crediting rate
Policyholder Account Balance [Line Items]
Policyholders' account balances	$ 670.8	$ 490.0

HORACE MANN EDUCATORS CORP /DE/ 10-Q