Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Change in net unrealized gain (loss) on investments, Pre-Tax Amount	$ 369	$ 634
Reclassification adjustment for realized losses, Pre-Tax Amount	12	(81)
Accumulated Other Comprehensive Income and (Loss), Pre-Tax Amount, End of period	4,635	4,254
Change in net unrealized gain (loss) on investments, Tax (Expense) Benefit	(144)
Reclassification adjustment for realized losses, Tax (Expense) Benefit	(5)
Accumulated Other Comprehensive Income (Loss), Tax (Expense) Benefit, End of period	(1,790)	(1,641)
Accumulated Other Comprehensive Income (Loss), Net-of-Tax Amount, Beginning of period	2,613
Change in net unrealized gain (loss) on investments, Net-of-Tax Amount	225
Reclassification adjustment for realized losses, Net-of-Tax Amount	7
Accumulated Other Comprehensive Income (Loss), Net-of-Tax Amount, End of period	$ 2,845	$ 2,613