Segment Reporting (Schedule Of Underwriting Results For Operating Segments) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information [Line Items]
Gross written premiums	$ 2,205,008	$ 2,133,334
Net written premiums	1,796,209	1,765,343
Premiums earned	1,828,592	1,696,900
Incurred losses and LAE	1,225,690	1,354,084
Commission and brokerage	384,630	349,854
Other underwriting expenses	117,755	109,795
Underwriting gain (loss)	100,517	(116,833)
Reinsurance [Member]
Segment Reporting Information [Line Items]
Gross written premiums	1,379,671	1,420,082
Net written premiums	1,185,341	1,208,813
Premiums earned	1,209,313	1,177,170
Incurred losses and LAE	820,471	970,318
Commission and brokerage	315,329	290,556
Other underwriting expenses	30,974	36,289
Underwriting gain (loss)	42,539	(119,994)
Insurance [Member]
Segment Reporting Information [Line Items]
Gross written premiums	825,337	713,252
Net written premiums	610,868	556,530
Premiums earned	619,279	519,730
Incurred losses and LAE	405,219	383,766
Commission and brokerage	69,300	59,298
Other underwriting expenses	86,782	73,505
Underwriting gain (loss)	$ 57,978	$ 3,161