Income Taxes (Schedule of Effective Income Tax Rate Reconciliation) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Statutory federal income tax rate		35.00%
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Computed “expected” tax expense	$ 333,269	$ 244,611	$ 245,675
Tax-exempt investment income	(38,757)	(40,679)	(50,665)
Change in valuation allowance	1,335	0	0
Impact of foreign tax rates	6,239	(4,851)	(5,234)
State and local taxes	2,375	2,906	(753)
Other, net	(1,868)	(8,400)	2,262
Total expense	$ 302,593us-gaap_IncomeTaxExpenseBenefit	$ 193,587us-gaap_IncomeTaxExpenseBenefit	$ 191,285us-gaap_IncomeTaxExpenseBenefit

Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to increase (decrease) in the valuation allowance for deferred tax assets.

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The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

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