Investments (Summary of Gross Unrealized Losses for Investments that have been Continuously in Unrealized Loss Position) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Schedule of Investments [Line Items]
Fair Value 12 months or less	$ 143,301	$ 113,255
Unrealized Losses 12 months or less	(1,976)	(1,287)
Fair Value Longer than 12 months	34,749	53,634
Unrealized Losses Longer than 12 months	(2,269)	(2,613)
Total Fair Value	178,050	166,889
Total Unrealized Losses	(4,245)	(3,900)
Equity Securities [Member]
Schedule of Investments [Line Items]
Fair Value 12 months or less	283	316
Unrealized Losses 12 months or less	(3)	(2)
Fair Value Longer than 12 months		2,721
Unrealized Losses Longer than 12 months		(312)
Total Fair Value	283	3,037
Total Unrealized Losses	(3)	(314)
Debt Securities [Member]
Schedule of Investments [Line Items]
Fair Value 12 months or less	143,018	112,939
Unrealized Losses 12 months or less	(1,973)	(1,285)
Fair Value Longer than 12 months	34,749	50,913
Unrealized Losses Longer than 12 months	(2,269)	(2,301)
Total Fair Value	177,767	163,852
Total Unrealized Losses	(4,242)	(3,586)
US Treasury Securities and Obligations of U.S. Government [Member] | Debt Securities [Member]
Schedule of Investments [Line Items]
Fair Value 12 months or less	29,723	47,162
Unrealized Losses 12 months or less	(76)	(165)
Total Fair Value	29,723	47,162
Total Unrealized Losses	(76)	(165)
Corporate Bonds [Member] | Debt Securities [Member]
Schedule of Investments [Line Items]
Fair Value 12 months or less	113	5,649
Unrealized Losses 12 months or less		(56)
Fair Value Longer than 12 months		4,421
Unrealized Losses Longer than 12 months		(394)
Total Fair Value	113	10,070
Total Unrealized Losses		(450)
Collateralized Corporate Bank Loans [Member] | Debt Securities [Member]
Schedule of Investments [Line Items]
Fair Value 12 months or less	72,134	23,026
Unrealized Losses 12 months or less	(874)	(422)
Fair Value Longer than 12 months	8,057	6,968
Unrealized Losses Longer than 12 months	(957)	(67)
Total Fair Value	80,191	29,994
Total Unrealized Losses	(1,831)	(489)
Municipal Bonds [Member] | Debt Securities [Member]
Schedule of Investments [Line Items]
Fair Value 12 months or less	30,834	35,719
Unrealized Losses 12 months or less	(787)	(413)
Fair Value Longer than 12 months	22,715	34,684
Unrealized Losses Longer than 12 months	(879)	(1,562)
Total Fair Value	53,549	70,403
Total Unrealized Losses	(1,666)	(1,975)
Mortgage Backed [Member] | Debt Securities [Member]
Schedule of Investments [Line Items]
Fair Value 12 months or less	10,214	1,383
Unrealized Losses 12 months or less	(236)	(229)
Fair Value Longer than 12 months	3,977	4,840
Unrealized Losses Longer than 12 months	(433)	(278)
Total Fair Value	14,191	6,223
Total Unrealized Losses	$ (669)	$ (507)