Investments (Number of Securities in an Unrealized Unrecognized Loss Position) (Details) (USD $)	9 Months Ended
	Sep. 30, 2012 Securities	Dec. 31, 2011 Securities
Schedule of Available-for-sale Securities [Line Items]
Unrealized Unrecognized Losses Period Increase Decrease	$ (8,100,000)
Number of securities in an unrealized/unrecognized loss position	47	141
Securities In Unrealized Unrecognized Loss Position For More Than Twelve Months Unrealized Unrecognized Loss	1,900,000	4,900,000
Unrealized Unrecognized Loss	2,578,000	10,635,000
Non-Credit OTTI Charges	1,200,000	2,100,000
Decline in fair value percentage	4.00%	6.00%
Eighty Percent to Ninety-Nine Percent [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of securities in an unrealized/unrecognized loss position	46	140
Unrealized Unrecognized Loss	2,335,000	10,166,000
Sixty Percent to Seventy-Nine Percent [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of securities in an unrealized/unrecognized loss position	1	0
Unrealized Unrecognized Loss	243,000	0
Forty Percent to Fifty-Nine Percent [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of securities in an unrealized/unrecognized loss position	0	1
Unrealized Unrecognized Loss	0	469,000
Twenty Percent to Thirty-Nine Percent [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of securities in an unrealized/unrecognized loss position	0	0
Unrealized Unrecognized Loss	0	0
Zero Percent to Nineteen Percent [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of securities in an unrealized/unrecognized loss position	0	0
Unrealized Unrecognized Loss	$ 0	$ 0