CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Statement of Financial Position [Abstract]
Amortized cost	$ 12,127,540	$ 12,419,905
Fixed maturities, available for sale, allowance for expected credit losses	5,043	3,938
Fixed maturities, held to maturity, fair value	400,790	436,751
Fixed maturities, held to maturity, allowance for expected credit losses	0	0
Equity securities, cost	529,074	520,743
Mortgage loans, held for investment, allowance for expected credit losses	27,335	23,378
Allowance for expected credit losses on insurance and reinsurance premium balances receivable	17,849	17,339
Allowance for expected credit losses on reinsurance recoverable for unpaid losses and loss expenses	$ 44,248	$ 43,445
Common shares, shares issued (in shares)	176,580	176,580
Common shares, shares outstanding (in shares)	78,173	82,984
Treasury shares, shares (in shares)	98,407	93,596