Liabilities for Losses and Loss Expenses (Details) - USD ($)	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Liability for Claims and Claims Adjustment Expense [Abstract]
Balance at January 1	$ 1,121,045,758	$ 1,077,620,000
Less reinsurance recoverable	(451,184,000)	(451,261,000)
Cumulative effect of adoption of updated accounting guidance for credit losses at January 1	1,132,000	0
Net balance at January 1	670,994,000	626,359,000
Incurred related to [Abstract]
Current year	297,801,000	283,906,000
Prior years	(8,460,000)	(24,415,000)
Total incurred	289,341,000	259,491,000
Paid related to [Abstract]
Current year	129,999,000	112,253,000
Prior years	152,890,000	130,441,000
Total paid	282,889,000	242,694,000
Net balance at end of period	677,446,000	643,156,000
Plus reinsurance recoverable	445,237,000	440,198,000
Balance at end of period	$ 1,122,683,198	$ 1,083,354,000
Percentage of development	1.30%	3.90%