Income Taxes (Net Deferred Income Tax Assets) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Income Taxes [Abstract]
Loss reserve	$ 159,320	$ 183,883
Foreign tax credits	90,941	74,253
Net operating loss carryforward	64,353	167,089
Alternative minimum tax credits	64,088	21,438
Deferred expenses	40,200	19,351
Unearned premium reserve	37,558	43,020
Unfunded pension liability	33,660	29,903
Deferred gain on reinsurance	30,265	31,464
Deferred compensation	6,690	7,243
Uncollectible reinsurance reserve	5,675	5,675
Investment impairments	3,009	4,478
Other assets	10,646	17,717
Total deferred tax assets	546,405	605,514
Net unrealized fair value income	139,374	20,990
Net unrealized investment gains	84,934	76,452
Net unrealized foreign currency gains	42,747	45,837
Deferred acquisition costs	33,969	58,571
Gain on tender of debt	27,395	27,395
Bond market discount	3,050	2,902
Other liabilities	761	6,877
Total deferred tax liabilities	332,230	239,024
Net deferred tax assets	$ 214,175	$ 366,490