Investment Information (Other Than Temporary Impairments Recognized in Earnings) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Total OTTI recognized in earnings	$ (2,246)	$ (1,023)
Fixed Maturities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Total OTTI recognized in earnings	(35)	(942)
Fixed Maturities | Mortgage backed securities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Total OTTI recognized in earnings	(15)	(746)
Fixed Maturities | Corporate bonds
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Total OTTI recognized in earnings	0	(196)
Fixed Maturities | Asset backed securities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Total OTTI recognized in earnings	(20)	0
Investment of funds received under securities lending arrangements
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Total OTTI recognized in earnings	0	(81)
Equity securities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Total OTTI recognized in earnings	$ (2,211)	$ 0