Investments (Credit Loss Component Of OTTI On Debt Securities Recognized In Earnings) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Mar. 31, 2013
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Beginning Balance	$ 26,658	$ 25,999
Additional credit impairment	576
Sold	(1,235)
Ending Balance	25,999	25,999
Debt Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Beginning Balance	20,610	21,186
Additional credit impairment	576
Ending Balance	21,186	21,186
Equity Securities [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Beginning Balance	6,048	4,813
Sold	(1,235)
Ending Balance	$ 4,813	$ 4,813