Loss And Loss Adjustment Expense Reserves (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	May 01, 2025	Apr. 11, 2025
Unusual or Infrequent Item, or Both [Line Items]
Prior years	$ (51,034)	$ (5,845)
Liability for catastrophe claims, carrying amount	447,000	72,000
Catastrophe
Unusual or Infrequent Item, or Both [Line Items]
Adjustments for prior year claims	(12,000)	$ 4,000
Fire
Unusual or Infrequent Item, or Both [Line Items]
Net catastrophe losses	414,000
Loss from catastrophes, directly incurred	331,000
Loss from catastrophes, share of indirect losses	83,000
Recoupable assessment	25,000
Estimate of possible loss	2,150,000
Estimated subrogation recoveries	525,000
Ceded loss from catastrophes	1,294,000
Total reinsurance used	1,294,000
Net catastrophe losses	331,000
Reinsurance limit	1,290,000
Retention per occurrence	150,000
Reinstatement premium	101,000
Reinsurance limit, amount reinstated	1,238,000
Reduction of reinsurance limit	6,500
Reinsurance limit, additional utilized amount net of loss reinsurance treaty	10,000
Reinstatement premiums written	101,000
Reinstatement premiums earned	50,000
Unearned reinstatement premiums	$ 50,000
Average payout percentage by utility companies	60.00%
Subrogation rights, percentage of subrogation recovery	55.00%
Loss from catastrophes, share of indirect losses, gross	$ 108,000
Assessment for shortfall	$ 50,000
Percentage of recoupable assesment	50.00%
Loss from catastrophes, estimate if events recorded separately	$ 296,000
Reinstatement premiums written, estimate if events recorded separately	92,000
Reinstatement premiums earned, estimate if events recorded separately	46,000
Amount paid out for claims	1,076,000
Amount billed to reinsurers	$ 606,000
Percent of collections from reinsurers	100.00%
Fire | Subsequent Event
Unusual or Infrequent Item, or Both [Line Items]
Amount billed to reinsurers				$ 224,000
Amount collected from reinsurers			$ 136,000
Fire | Minimum
Unusual or Infrequent Item, or Both [Line Items]
Average payout percentage by utility companies	55.00%
Fire | Maximum
Unusual or Infrequent Item, or Both [Line Items]
Average payout percentage by utility companies	70.00%