Reserves for Losses and Loss Settlement Expenses (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Gross liability for losses and loss settlement expenses at beginning of year	$ 1,497,274	$ 1,514,265
Ceded losses and loss settlement expenses	(146,875)	(112,900)
Net liability for losses and loss settlement expenses at beginning of year	1,350,399	1,401,365
Losses and loss settlement expenses incurred for claims occurring during
Current year	538,941	624,411
Prior years	59,184	12,890
Total incurred	598,125	637,301
Losses and loss settlement expense payments for claims occurring during
Current year	131,408	215,891
Prior years	371,723	472,377
Total paid	503,131	688,268
Net liability for losses and loss settlement expenses at end of period	1,445,394	1,350,399
Ceded losses and loss settlement expenses	191,525	146,875
Gross liability for losses and loss settlement expenses at end of period	$ 1,636,918	$ 1,497,274