Investments - Net Investment Income (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Net Investment Income [Line Items]
Gross investment income		$ 75,802	$ 76,520	$ 147,258	$ 148,666
Investment expenses	[1]	(3,033)	(2,754)	(5,915)	(5,679)
Net investment income		72,769	73,766	141,343	142,987
Fixed-maturities
Net Investment Income [Line Items]
Gross investment income		57,835	57,924	114,549	115,183
Equity securities
Net Investment Income [Line Items]
Gross investment income		2,634	3,067	4,779	5,606
Residential mortgage loans held for sale
Net Investment Income [Line Items]
Gross investment income	[2]	10,064	5,411	16,337	7,204
Short-term investments
Net Investment Income [Line Items]
Gross investment income		3,409	8,614	8,160	17,572
Other
Net Investment Income [Line Items]
Gross investment income	[1]	$ 1,860	$ 1,504	$ 3,433	$ 3,101

[1] Includes the impact from our securities lending activities. Investment expenses also include other investment management expenses.

[2] See Note 7 for additional information on our residential mortgage loans held for sale.