Investments (Details 2) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Gross unrealized losses of the Company's investment portfolio
Less than 12 months, Fair Value	$ 24,061	$ 71,069
12 months or longer, Fair Value	56	5,432
Total, Fair Value	24,117	76,501
Temporarily impaired securities, Less than 12 months, Fair Value	30,987	79,256
Temporarily impaired securities, 12 months or longer, Fair Value	571	5,941
Temporarily impaired securities, Fair Value	31,558	85,197
Less than 12 months, Unrealized Losses	(327)	(1,476)
12 months or longer, Unrealized Losses	(11)	(43)
Total, Unrealized Losses	(338)	(1,519)
Temporarily impaired securities, Less than 12 months, Unrealized Losses	(547)	(1,701)
Temporarily impaired securities, 12 months or longer, Unrealized Losses	(23)	(62)
Temporarily impaired securities, Unrealized Losses	(570)	(1,763)
U.S. Treasury securities and other government corporations and agencies [Member]
Gross unrealized losses of the Company's investment portfolio
Less than 12 months, Fair Value		3,749
12 months or longer, Fair Value
Total, Fair Value		3,749
Less than 12 months, Unrealized Losses		(39)
12 months or longer, Unrealized Losses
Total, Unrealized Losses		(39)
States of the U.S. and political subdivisions of the states [Member]
Gross unrealized losses of the Company's investment portfolio
Less than 12 months, Fair Value	6,555
12 months or longer, Fair Value
Total, Fair Value	6,555
Less than 12 months, Unrealized Losses	(57)
12 months or longer, Unrealized Losses
Total, Unrealized Losses	(57)
Corporate securities [Member]
Gross unrealized losses of the Company's investment portfolio
Less than 12 months, Fair Value	4,476	31,808
12 months or longer, Fair Value
Total, Fair Value	4,476	31,808
Less than 12 months, Unrealized Losses	(51)	(1,127)
12 months or longer, Unrealized Losses
Total, Unrealized Losses	(51)	(1,127)
Mortgage-backed securities [Member]
Gross unrealized losses of the Company's investment portfolio
Less than 12 months, Fair Value	5,071	6,574
12 months or longer, Fair Value
Total, Fair Value	5,071	6,574
Less than 12 months, Unrealized Losses	(102)	(26)
12 months or longer, Unrealized Losses
Total, Unrealized Losses	(102)	(26)
Commercial mortgage-backed securities [Member]
Gross unrealized losses of the Company's investment portfolio
Less than 12 months, Fair Value	5,540	13,401
12 months or longer, Fair Value		5,432
Total, Fair Value	5,540	18,833
Less than 12 months, Unrealized Losses	(98)	(135)
12 months or longer, Unrealized Losses		(43)
Total, Unrealized Losses	(98)	(178)
Asset-backed securities [Member]
Gross unrealized losses of the Company's investment portfolio
Less than 12 months, Fair Value	2,419	15,537
12 months or longer, Fair Value	56
Total, Fair Value	2,475	15,537
Less than 12 months, Unrealized Losses	(19)	(149)
12 months or longer, Unrealized Losses	(11)
Total, Unrealized Losses	(30)	(149)
Common stock [Member]
Gross unrealized losses of the Company's investment portfolio
12 months or longer, Fair Value
Temporarily impaired securities, Less than 12 months, Fair Value	6,926	6,751
Temporarily impaired securities, Fair Value	6,926	6,751
12 months or longer, Unrealized Losses
Temporarily impaired securities, Less than 12 months, Unrealized Losses	(220)	(175)
Temporarily impaired securities, Unrealized Losses	(220)	(175)
Preferred stock [Member]
Gross unrealized losses of the Company's investment portfolio
Temporarily impaired securities, Less than 12 months, Fair Value		1,436
Temporarily impaired securities, 12 months or longer, Fair Value	515	509
Temporarily impaired securities, Fair Value	515	1,945
Temporarily impaired securities, Less than 12 months, Unrealized Losses		(50)
Temporarily impaired securities, 12 months or longer, Unrealized Losses	(12)	(19)
Temporarily impaired securities, Unrealized Losses	$ (12)	$ (69)