Investments (Allowance for Losses) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Allowance For Losses On Commermcial Mortgage And Other Loans [Line Items]
Allowance for Losses, Beginning Balance	$ 1,501	[1]	$ 2,980	[1]	$ 2,897
Addition To / (Release of) Allowance For Losses	676		(1,479)		83
Allowance for Losses, Ending Balance	2,177	[1]	1,501	[1]	2,980	[1]
Agricultural Property Loans [Member]
Allowance For Losses On Commermcial Mortgage And Other Loans [Line Items]
Allowance for Losses, Ending Balance	$ 200		$ 200		$ 200

[1] (1) Agricultural loans represent $0.2 million of the ending allowance at December 31, 2012, 2011 and 2010, respectively.