Schedule VI-Supplementary Information Concerning Property-Casualty Insurance Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Claims and claim adjustment expenses incurred related to:
Current accident year	$ 834,562	$ 712,960	$ 636,955
Prior accident year	(95,309)	(108,547)	(122,579)
Consolidated Property-Casualty Insurance Operations
Supplemental Information For Property Casualty Insurance Underwriters [Line Items]
Deferred policy acquisition costs	166,214	146,566	127,859
Claims and claim adjustment expense reserves	2,693,470	2,446,025	2,315,637
Unearned premiums, gross	984,140	892,326	785,085
Net premiums earned	1,526,406	1,294,306	1,144,436
Net investment income	142,278	120,383	86,078
Claims and claim adjustment expenses incurred related to:
Current accident year	834,562	712,960	636,955
Prior accident year	(95,309)	(108,547)	(122,579)
Amortization of deferred acquisition costs	318,021	418,325	369,632
Paid claims and claims adjustment expenses	489,884	491,285	374,297
Net premiums written	$ 1,605,521	$ 1,427,747	$ 1,241,536