Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Deferred tax assets:
Other employee benefits	$ 18,409	$ 17,781
Allowance for management fee returned on cancelled policies	4,647	3,571
Deferred revenue	4,181	3,756
Unrealized losses on investments	3,827	7,164
Current expected credit loss allowance	2,966	2,661
Other	4,617	3,709
Total deferred tax assets	38,647	38,642
Deferred tax liabilities:
Depreciation	27,089	31,126
Pension and other postretirement benefits	12,276	14,738
Prepaid expenses	2,013	2,001
Other	3,687	2,258
Total deferred tax liabilities	45,065	50,123
Net deferred tax liability	$ (6,418)	$ (11,481)