Investments (Details 4) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Gross unrecognized and unrealized losses of the Company's investment portfolio
Less than 12 months, Fair Value	$ 73,355	$ 71,069
12 months or longer, Fair Value	3,810	5,432
Total, Fair Value	77,165	76,501
Temporarily impaired securities, Less than 12 months, Fair Value	74,912	79,256
Temporarily impaired securities, 12 months or longer, Fair Value	11,240	5,941
Temporarily impaired securities, Fair Value	86,152	85,197
Less than 12 months, Unrealized Losses	(642)	(1,476)
12 months or longer, Unrealized Losses	(174)	(43)
Total, Unrealized Losses	(816)	(1,519)
Temporarily impaired securities, Less than 12 months, Unrealized Losses	(658)	(1,701)
Temporarily impaired securities, 12 months or longer, Unrealized Losses	(417)	(62)
Temporarily impaired securities, Unrealized Losses	(1,075)	(1,763)
U.S. Treasury securities and obligations of U.S. Government corporations and agencies [Member]
Gross unrecognized and unrealized losses of the Company's investment portfolio
Less than 12 months, Fair Value	4,985	3,749
12 months or longer, Fair Value
Total, Fair Value	4,985	3,749
Less than 12 months, Unrealized Losses	(11)	(39)
12 months or longer, Unrealized Losses
Total, Unrealized Losses	(11)	(39)
States of the U.S. and political subdivisions of the states [Member]
Gross unrecognized and unrealized losses of the Company's investment portfolio
Less than 12 months, Fair Value
12 months or longer, Fair Value
Total, Fair Value
Less than 12 months, Unrealized Losses
12 months or longer, Unrealized Losses
Total, Unrealized Losses
Corporate securities [Member]
Gross unrecognized and unrealized losses of the Company's investment portfolio
Less than 12 months, Fair Value	24,489	31,808
12 months or longer, Fair Value
Total, Fair Value	24,489	31,808
Less than 12 months, Unrealized Losses	(85)	(1,127)
12 months or longer, Unrealized Losses
Total, Unrealized Losses	(85)	(1,127)
Mortgage-backed securities [Member]
Gross unrecognized and unrealized losses of the Company's investment portfolio
Less than 12 months, Fair Value	36,345	6,574
12 months or longer, Fair Value	3,751
Total, Fair Value	40,096	6,574
Less than 12 months, Unrealized Losses	(336)	(26)
12 months or longer, Unrealized Losses	(165)
Total, Unrealized Losses	(501)	(26)
Commercial mortgage-backed securities [Member]
Gross unrecognized and unrealized losses of the Company's investment portfolio
Less than 12 months, Fair Value		13,401
12 months or longer, Fair Value		5,432
Total, Fair Value		18,833
Less than 12 months, Unrealized Losses		(135)
12 months or longer, Unrealized Losses		(43)
Total, Unrealized Losses		(178)
Asset-backed securities [Member]
Gross unrecognized and unrealized losses of the Company's investment portfolio
Less than 12 months, Fair Value	7,536	15,537
12 months or longer, Fair Value	59
Total, Fair Value	7,595	15,537
Less than 12 months, Unrealized Losses	(210)	(149)
12 months or longer, Unrealized Losses	(9)
Total, Unrealized Losses	(219)	(149)
Common stock [Member]
Gross unrecognized and unrealized losses of the Company's investment portfolio
Temporarily impaired securities, Less than 12 months, Fair Value	1,067	6,751
Temporarily impaired securities, 12 months or longer, Fair Value	6,926
Temporarily impaired securities, Fair Value	7,993	6,751
Temporarily impaired securities, Less than 12 months, Unrealized Losses	(14)	(175)
Temporarily impaired securities, 12 months or longer, Unrealized Losses	(220)
Temporarily impaired securities, Unrealized Losses	(234)	(175)
Preferred stock [Member]
Gross unrecognized and unrealized losses of the Company's investment portfolio
Temporarily impaired securities, Less than 12 months, Fair Value	490	1,436
Temporarily impaired securities, 12 months or longer, Fair Value	504	509
Temporarily impaired securities, Fair Value	994	1,945
Temporarily impaired securities, Less than 12 months, Unrealized Losses	(2)	(50)
Temporarily impaired securities, 12 months or longer, Unrealized Losses	(23)	(19)
Temporarily impaired securities, Unrealized Losses	$ (25)	$ (69)