Segment and Other Operating Information - Net Earnings (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Segment Reporting Information [Line Items]
Net earnings	$ 29,634	$ 96,527	$ 41,938	$ 194,089
Total segment assets
Segment Reporting Information [Line Items]
Net earnings	29,613	95,132	41,865	189,697
Segment Reconciling Items
Segment Reporting Information [Line Items]
Realized gains on investments, net of taxes	$ 21	$ 1,395	$ 73	$ 4,392