Investments - Schedule of Other Long-Term Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Long-Term Investment [Line Items]
Commercial mortgage loan participations	$ 1,010,136	$ 976,016
Commercial mortgage loan participations
Long-Term Investment [Line Items]
Commercial mortgage loan participations	221,466	181,305
Other
Long-Term Investment [Line Items]
Commercial mortgage loan participations	29,513	26,022
Partnership Interest - Fair Value Option | Investment funds
Long-Term Investment [Line Items]
Commercial mortgage loan participations	$ 759,157	$ 768,689