Investments (Summary of Gross Unrealized Losses for Investments that have been Continuously in Unrealized Loss Position) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Schedule of Investments [Line Items]
Fair Value 12 months or less	$ 107,157	$ 81,876
Unrealized Losses 12 months or less	(2,522)	(1,047)
Fair Value Longer than 12 months	49,023	50,039
Unrealized Losses Longer than 12 months	(2,244)	(3,782)
Total Fair Value	156,180	131,915
Total Unrealized Losses	(4,766)	(4,829)
Equity Securities [Member]
Schedule of Investments [Line Items]
Fair Value 12 months or less	2,348	3,363
Unrealized Losses 12 months or less	(722)	(515)
Total Fair Value	2,348	3,363
Total Unrealized Losses	(722)	(515)
Debt Securities [Member]
Schedule of Investments [Line Items]
Fair Value 12 months or less	104,809	78,513
Unrealized Losses 12 months or less	(1,800)	(532)
Fair Value Longer than 12 months	49,023	50,039
Unrealized Losses Longer than 12 months	(2,244)	(3,782)
Total Fair Value	153,832	128,552
Total Unrealized Losses	(4,044)	(4,314)
Us Treasury Securities and Obligations of U.S. Government [Member] | Debt Securities [Member]
Schedule of Investments [Line Items]
Fair Value 12 months or less		23,998
Unrealized Losses 12 months or less		(3)
Total Fair Value		23,998
Total Unrealized Losses		(3)
Corporate Bonds [Member] | Debt Securities [Member]
Schedule of Investments [Line Items]
Fair Value 12 months or less	12,694	10,802
Unrealized Losses 12 months or less	(156)	(38)
Fair Value Longer than 12 months	3,048	6,910
Unrealized Losses Longer than 12 months	(369)	(725)
Total Fair Value	15,742	17,712
Total Unrealized Losses	(525)	(763)
Collateralized Corporate Bank Loans [Member] | Debt Securities [Member]
Schedule of Investments [Line Items]
Fair Value 12 months or less	48,926	6,273
Unrealized Losses 12 months or less	(368)	(97)
Fair Value Longer than 12 months	6,915	14,236
Unrealized Losses Longer than 12 months	(181)	(646)
Total Fair Value	55,841	20,509
Total Unrealized Losses	(549)	(743)
Municipal Bonds [Member] | Debt Securities [Member]
Schedule of Investments [Line Items]
Fair Value 12 months or less	28,861	30,073
Unrealized Losses 12 months or less	(488)	(362)
Fair Value Longer than 12 months	38,953	28,809
Unrealized Losses Longer than 12 months	(1,691)	(2,408)
Total Fair Value	67,814	58,882
Total Unrealized Losses	(2,179)	(2,770)
Mortgage Backed [Member] | Debt Securities [Member]
Schedule of Investments [Line Items]
Fair Value 12 months or less	14,328	7,367
Unrealized Losses 12 months or less	(788)	(32)
Fair Value Longer than 12 months	107	84
Unrealized Losses Longer than 12 months	(3)	(3)
Total Fair Value	14,435	7,451
Total Unrealized Losses	(791)	(35)
Financial Services [Member] | Equity Securities [Member]
Schedule of Investments [Line Items]
Fair Value 12 months or less		92
Unrealized Losses 12 months or less		(1)
Total Fair Value		92
Total Unrealized Losses		(1)
All Other [Member] | Equity Securities [Member]
Schedule of Investments [Line Items]
Fair Value 12 months or less	2,348	3,271
Unrealized Losses 12 months or less	(722)	(514)
Total Fair Value	2,348	3,271
Total Unrealized Losses	$ (722)	$ (514)