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Retirement Plans (Tables) | 12 Months Ended
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Dec. 31, 2024
Retirement Benefits [Abstract] |
Schedule of Defined Benefit Plans Disclosures [Table Text Block] | The funded status and amounts recognized on the 2024 and 2023 consolidated balance sheets for the RAP and Postretirement Plan were as follows:
| RAP | Postretirement Plan | RAP | Postretirement Plan
($ in thousands) | 2024 | 2024 | 2023 | 2023
Change in fair value of plan assets |  |  |  |
Fair value of plan assets at beginning of year | $ | 453,457 |  | $ | — |  | $ | 407,405 |  | $ | — |
Actual return on plan assets | 43,676 |  | — |  | 60,565 |  | — |
Employer contributions | — |  | 183 |  | — |  | 171 |
Gross benefits paid | (18,163) |  | (183) |  | (14,513) |  | (171) |
Fair value of plan assets at end of year(a) | $ | 478,970 |  | $ | — |  | $ | 453,457 |  | $ | — |
Change in benefit obligation |  |  |  |
Net benefit obligation at beginning of year | $ | 211,353 |  | $ | 1,425 |  | $ | 208,315 |  | $ | 1,530 |
Service cost | 3,027 |  | — |  | 3,189 |  | — |
Interest cost | 11,173 |  | 73 |  | 10,887 |  | 78 |
Actuarial loss (gain) | 5,975 |  | 729 |  | 3,475 |  | (12) |
Gross benefits paid | (18,163) |  | (183) |  | (14,513) |  | (171) |
Net benefit obligation at end of year(a) | $ | 213,365 |  | $ | 2,043 |  | $ | 211,353 |  | $ | 1,425 |
Funded (unfunded) status | $ | 265,605 |  | $ | (2,043) |  | $ | 242,104 |  | $ | (1,425) |
Noncurrent assets | $ | 265,605 |  | $ | — |  | $ | 242,104 |  | $ | — |
Current liabilities | — |  | (212) |  | — |  | (158) |
Noncurrent liabilities | — |  | (1,832) |  | — |  | (1,267) |
Asset (liability) recognized on the consolidated balance sheets | $ | 265,605 |  | $ | (2,043) |  | $ | 242,104 |  | $ | (1,425) |
(a) The fair value of the plan assets represented 224% and 215% of the net benefit obligation of the pension plan at December 31, 2024 and 2023, respectively.
Schedule of Net Periodic Benefit Cost Not yet Recognized [Table Text Block] | Amounts recognized in accumulated other comprehensive (income) loss, net of tax, were as follows:
| RAP | Postretirement Plan | RAP | Postretirement Plan
($ in thousands) | 2024 | 2024 | 2023 | 2023
Prior service cost | $ | (723) |  | $ | (252) |  | $ | (884) |  | $ | (308) |
Net actuarial loss (gain) | 24,758 |  | 267 |  | 27,089 |  | (301) |
Amount not yet recognized in net periodic benefit cost, but recognized in accumulated other comprehensive (income) loss | $ | 24,035 |  | $ | 15 |  | $ | 26,204 |  | $ | (609) |
Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block] | Other changes in plan assets and benefit obligations recognized in OCI, net of tax were as follows:
| RAP | Postretirement Plan | RAP | Postretirement Plan
($ in thousands) | 2024 | 2024 | 2023 | 2023
Net actuarial gain (loss) | $ | 3,102 |  | $ | (729) |  | $ | 24,228 |  | $ | 12 |
Amortization of prior service cost | (215) |  | (75) |  | (250) |  | (75) |
Amortization of actuarial loss (gain) | — |  | (28) |  | — |  | (29) |
Income tax (expense) benefit | (718) |  | 208 |  | (6,327) |  | 23 |
Total recognized in OCI | $ | 2,169 |  | $ | (624) |  | $ | 17,650 |  | $ | (68) |
Schedule of Net Benefit Costs [Table Text Block] | The components of net periodic pension cost for the RAP were as follows:
($ in thousands) | 2024 | 2023 | 2022
Service cost | $ | 3,027 |  | $ | 3,189 |  | $ | 3,670 |
Interest cost | 11,173 |  | 10,887 |  | 7,152 |
Expected return on plan assets | (34,599) |  | (32,862) |  | (26,903) |
Amortization of prior service cost | (215) |  | (250) |  | (250) |
Amortization of actuarial loss | — |  | — |  | 658 |
Total net periodic pension (income) | $ | (20,614) |  | $ | (19,037) |  | $ | (15,673) |
Net period benefit cost for postretirement plan | The components of net periodic benefit cost for the Postretirement Plan were as follows:
($ in thousands) | 2024 | 2023 | 2022
Interest cost | $ | 73 |  | $ | 78 |  | $ | 53 |
Amortization of prior service cost | (75) |  | (75) |  | (75) |
Amortization of actuarial (gain) | (28) |  | (29) |  | — |
Total net periodic benefit (income) | $ | (31) |  | $ | (26) |  | $ | (22) |
Defined Benefit Plan, Assumptions [Table Text Block] |
| RAP | Postretirement Plan | RAP | Postretirement Plan
| 2024 | 2024 | 2023 | 2023
Weighted average assumptions used to determine benefit obligations |  |  |  |
Discount rate | 5.40 | % | 5.40 | % | 5.40 | % | 5.40 | %
Rate of increase in compensation levels | 2.50 | % | N/A | 2.50 | % | N/A
Interest crediting rate | 3.81 | % | N/A | 3.77 | % | N/A
Weighted average assumptions used to determine net periodic benefit costs |  |  |  |
Discount rate | 5.40 | % | 5.40 | % | 5.40 | % | 5.40 | %
Rate of increase in compensation levels | 2.50 | % | N/A | 2.50 | % | N/A
Expected long-term rate of return on plan assets | 7.40 | % | N/A | 7.30 | % | N/A
Schedule of Allocation of Plan Assets [Table Text Block] | The asset allocation for the RAP as of the December 31, 2024 and 2023 measurement dates, respectively, by asset category were as follows:
Asset Category | 2024 | 2023
Equity securities | 55 | % | 54 | %
Fixed-income securities | 35 | % | 34 | %
Group annuity contracts | 8 | % | 10 | %
Other | 2 | % | 2 | %
Total | 100 | % | 100 | %
Defined Benefit Plan, Plan Assets, Category [Table Text Block] | Based on these inputs, the following tables summarize the fair value of the RAP’s investments:
|  | Fair Value Measurements Using
($ in thousands) | December 31, 2024 | Level 1 | Level 2 | Level 3
RAP investments |  |  |  |
Money market account | $ | 7,892 |  | $ | 7,892 |  | $ | — |  | $ | — |
Common /collective trust funds | 183,059 |  | 183,059 |  | — |  | — |
Mutual funds | 247,602 |  | 247,602 |  | — |  | — |
Group annuity contract | 40,416 |  | — |  | — |  | 40,416 |
Total RAP investments | $ | 478,970 |  | $ | 438,554 |  | $ | — |  | $ | 40,416 |
|  | Fair Value Measurements Using
($ in thousands) | December 31, 2023 | Level 1 | Level 2 | Level 3
RAP investments |  |  |  |
Money market account | $ | 10,040 |  | $ | 10,040 |  | $ | — |  | $ | — |
Common /collective trust funds | 164,891 |  | 164,891 |  | — |  | — |
Mutual funds | 234,840 |  | 234,840 |  | — |  | — |
Group annuity contract | 43,687 |  | — |  | — |  | 43,687 |
Total RAP investments | $ | 453,457 |  | $ | 409,771 |  | $ | — |  | $ | 43,687 |
Schedule of Changes in Fair Value of Plan Assets | The following presents a summary of the changes in the fair value of the RAP's Level 3 asset during the periods indicated.
Fair Value Reconciliation of Level 3 RAP Investments | 2024 | 2023
Fair value of group annuity contract at beginning of period | $ | 43,687 |  | $ | 40,939 |
Return on plan assets | (731) |  | 5,313 |
Benefits paid | (2,539) |  | (2,565) |
Fair value of group annuity contract at end of period | $ | 40,416 |  | $ | 43,687 |
Schedule of Expected Benefit Payments [Table Text Block] | The projected benefit payments were calculated using the same assumptions as those used to calculate the benefit obligations listed above. The projected benefit payments for the RAP and Postretirement Plan at December 31, 2024, reflecting expected future services, were as follows:
($ in thousands) | RAP | Postretirement Plan
Estimated future benefit payments |  |
2025 | $ | 22,579 |  | $ | 217 |
2026 | 21,689 |  | 213 |
2027 | 20,165 |  | 208 |
2028 | 20,135 |  | 203 |
2029 | 20,179 |  | 196 |
2030-2034 | 84,031 |  | 856 |

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