Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income and (Loss), Pre-Tax Amount, Beginning of period			$ 3,812
Change in net unrealized gain (loss) on investments, Pre-Tax Amount	1,442	2,441	3,042	3,470
Reclassification adjustment for realized losses, Pre-Tax Amount	(37)		(155)	(112)
Accumulated Other Comprehensive Income and (Loss), Pre-Tax Amount, End of period	6,699		6,699
Accumulated Other Comprehensive Income (Loss), Tax (Expense) Benefit, Beginning of period			(1,471)
Change in net unrealized gain (loss) on investments, Tax (Expense) Benefit			(1,174)
Reclassification adjustment for realized losses, Tax (Expense) Benefit			60
Accumulated Other Comprehensive Income (Loss), Tax (Expense) Benefit, End of period	(2,585)		(2,585)
Accumulated Other Comprehensive Income (Loss), Net-of-Tax Amount, Beginning of period			2,341
Change in net unrealized gain (loss) on investments, Net-of-Tax Amount			1,868
Reclassification adjustment for realized losses, Net-of-Tax Amount			(95)
Accumulated Other Comprehensive Income (Loss), Net-of-Tax Amount, End of period	$ 4,114		$ 4,114