Adoption of New Accounting Standards (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net investment income	$ 191,596	$ 188,051	[1]
Total revenue	1,022,532	1,024,171	[1]
Income before income taxes	180,432	197,538	[1]
Income taxes	(58,784)	(64,682)	[1]
Net income	121,648	132,856	[1]
As Previously Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net investment income		181,000
Total revenue		1,017,120
Income before income taxes		190,487
Income taxes		(57,631)
Net income		132,856
Adjustments [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net investment income		7,051
Total revenue		7,051
Income before income taxes		7,051
Income taxes		(7,051)
Net income		$ 0

[1] Certain balances were retrospectively adjusted to give effect to the adoption of new accounting guidance as described in Note G- Adoption of New Accounting Standards