Industry Segments (Financial Information of Company Operating Segments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Segment Reporting Information [Line Items]
Earned Premiums	$ 1,363,612		$ 1,232,119
Investment Income and Funds	168,711		135,929
Other Revenues	174,583		138,721
Total revenues	1,706,906		1,506,769
Pre-Tax Income (Loss)	247,585		160,223
Net Income (Loss)	169,673		116,615
Net investment gains	52,754		19,969
Net investment gains, net of tax	34,290		12,980
Intersegment Eliminations and Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Earned Premiums	0	[1]	0	[1]
Investment Income and Funds	6,344	[1]	3,572	[1]
Other Revenues	93,063	[1]	92,016	[1]
Total revenues	99,407	[1]	95,588	[1]
Pre-Tax Income (Loss)	(57,175)	[1]	(61,419)	[1]
Net Income (Loss)	(37,513)	[1]	(37,644)	[1]
Insurance-Domestic Segment [Member]
Segment Reporting Information [Line Items]
Earned Premiums	1,003,507		884,378
Insurance-Domestic Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Earned Premiums	1,003,507		884,378
Investment Income and Funds	118,137		97,797
Other Revenues	28,766		26,736
Total revenues	1,150,410		1,008,911
Pre-Tax Income (Loss)	202,185		141,350
Net Income (Loss)	138,036		99,408
Insurance-International Segment [Member]
Segment Reporting Information [Line Items]
Earned Premiums	185,324		171,119
Insurance-International Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Earned Premiums	185,324		171,119
Investment Income and Funds	16,652		12,061
Other Revenues	0		0
Total revenues	201,976		183,180
Pre-Tax Income (Loss)	17,747		22,382
Net Income (Loss)	12,468		15,477
Reinsurance-Global Segment [Member]
Segment Reporting Information [Line Items]
Earned Premiums	174,781		176,622
Reinsurance-Global Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Earned Premiums	174,781		176,622
Investment Income and Funds	27,578		22,499
Other Revenues	0		0
Total revenues	202,359		199,121
Pre-Tax Income (Loss)	32,074		37,941
Net Income (Loss)	$ 22,392		$ 26,394

[1] {F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOjg3ZTg4YTYzZTE5OTQ1MGQ5ZGZjMjQ0Y2JjYzAxNDY3fFRleHRTZWxlY3Rpb246MDdDNkE3ODY2NzRGNURFQjkyQThGM0M0Q0Q0QjlCOEUM}