Industry Segments (Financial Information of Company Operating Segments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Segment Reporting Information [Line Items]
Earned Premiums	$ 1,472,013		$ 1,363,612
Investment Income and Funds	124,239		168,711
Other Revenues	148,427		174,583
Total revenues	1,744,679		1,706,906
Pre-Tax Income (Loss)	168,717		247,585
Net Income (Loss)	118,307		169,673
Net investment gains	19,044		52,754
Net investment gains, net of tax	12,379		34,290
Intersegment Eliminations and Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Earned Premiums	0	[1]	0	[1]
Investment Income and Funds	8,114	[1]	6,344	[1]
Other Revenues	103,808	[1]	93,063	[1]
Total revenues	111,922	[1]	99,407	[1]
Pre-Tax Income (Loss)	(58,758)	[1]	(57,175)	[1]
Net Income (Loss)	(38,611)	[1]	(37,513)	[1]
Insurance-Domestic Segment [Member]
Segment Reporting Information [Line Items]
Earned Premiums	1,117,542		1,003,507
Insurance-Domestic Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Earned Premiums	1,117,542		1,003,507
Investment Income and Funds	82,652		118,137
Other Revenues	25,575		28,766
Total revenues	1,225,769		1,150,410
Pre-Tax Income (Loss)	166,866		202,185
Net Income (Loss)	114,910		138,036
Insurance-International Segment [Member]
Segment Reporting Information [Line Items]
Earned Premiums	193,734		185,324
Insurance-International Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Earned Premiums	193,734		185,324
Investment Income and Funds	16,432		16,652
Other Revenues	0		0
Total revenues	210,166		201,976
Pre-Tax Income (Loss)	21,303		17,747
Net Income (Loss)	15,129		12,468
Reinsurance-Global Segment [Member]
Segment Reporting Information [Line Items]
Earned Premiums	160,737		174,781
Reinsurance-Global Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Earned Premiums	160,737		174,781
Investment Income and Funds	17,041		27,578
Other Revenues	0		0
Total revenues	177,778		202,359
Pre-Tax Income (Loss)	20,262		32,074
Net Income (Loss)	$ 14,500		$ 22,392

[1] {F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOjk1YWZhMDc0NWFiZTQxMzliNWExNjhjZWYxMzc0NGYxfFRleHRTZWxlY3Rpb246MDlEOEY3Qjg0Q0FENUI4MUJBRDA4NEFFRUExMDVFNTcM}