Schedule VI-Supplementary Information Concerning Property-Casualty Insurance Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Claims and claim adjustment expenses incurred related to:
Current accident year	$ 712,960	$ 636,955	$ 582,065
Prior accident years	(108,547)	(122,579)	(125,463)
Amortization of deferred acquisition costs	418,325	369,632	317,468
Consolidated Property-Casualty Insurance Operations
Supplemental Information For Property Casualty Insurance Underwriters [Line Items]
Deferred policy acquisition costs	146,566	127,859	103,553
Claims and claim adjustment expense reserves	2,446,025	2,315,637	2,043,555
Unearned premiums, gross	892,326	785,085	680,444
Net premiums earned	1,294,306	1,144,436	980,903
Net investment income	120,383	86,078	68,862
Claims and claim adjustment expenses incurred related to:
Current accident year	712,960	636,955	582,065
Prior accident years	(108,547)	(122,579)	(125,463)
Amortization of deferred acquisition costs	418,325	369,632	317,468
Paid claims and claims adjustment expenses	491,285	374,297	327,453
Net premiums written	$ 1,427,747	$ 1,241,536	$ 1,057,533