Investments (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
A summary of the Company's realized gains and losses on sales, calls or redemptions of investments
Proceeds from sales									$ 33,140	$ 36,329	$ 30,157
Gross realized investment gains									2,741	2,436	2,650
Gross realized investment (losses)										(99)
Net realized investment gain									2,741	2,337	2,650
Impairments										(169)	(693)
Other, including gains on calls and redemptions									238	60	492
Net realized investment gains	66	985	137	1,791	1,468	512	145	103	2,979	2,228	2,449
Fixed Maturity Securities Available for Sale [Member]
A summary of the Company's realized gains and losses on sales, calls or redemptions of investments
Proceeds from sales									22,363	21,560	15,462
Gross realized investment gains									1,555	815
Gross realized investment (losses)
Net realized investment gain									1,555	815
Other, including gains on calls and redemptions									15		411
Net realized investment gains									1,570	815	411
Equity Securities [Member]
A summary of the Company's realized gains and losses on sales, calls or redemptions of investments
Proceeds from sales									10,777	14,769	14,695
Gross realized investment gains									1,186	1,621	2,650
Gross realized investment (losses)										(98)
Net realized investment gain									1,186	1,523	2,650
Impairments											(693)
Net realized investment gains									1,186	1,523	1,957
Other [Member]
A summary of the Company's realized gains and losses on sales, calls or redemptions of investments
Gross realized investment (losses)										(1)
Net realized investment gain										(1)
Impairments										(169)
Other, including gains on calls and redemptions									223	60	81
Net realized investment gains									$ 223	$ (110)	$ 81