Investments (Summary of Gross Unrealized Loss Position) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Fair Value 12 months or less	$ 158,413	$ 113,255
Unrealized Losses 12 months or less	(2,225)	(1,287)
Fair Value Longer than 12 months	27,548	53,634
Unrealized Losses Longer than 12 months	(1,752)	(2,613)
Fair Value Total	185,961	166,889
Unrealized Losses Total	(3,977)	(3,900)
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value 12 months or less	158,284	112,939
Unrealized Losses 12 months or less	(2,223)	(1,285)
Fair Value Longer than 12 months	27,548	50,913
Unrealized Losses Longer than 12 months	(1,752)	(2,301)
Fair Value Total	185,832	163,852
Unrealized Losses Total	(3,975)	(3,586)
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value 12 months or less	129	316
Unrealized Losses 12 months or less	(2)	(2)
Fair Value Longer than 12 months		2,721
Unrealized Losses Longer than 12 months		(312)
Fair Value Total	129	3,037
Unrealized Losses Total	(2)	(314)
U.S. Treasury securities and obligations of U.S. Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value 12 months or less	15,005	47,162
Unrealized Losses 12 months or less	(4)	(165)
Fair Value Total	15,005	47,162
Unrealized Losses Total	(4)	(165)
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value 12 months or less	7,552	5,649
Unrealized Losses 12 months or less	(85)	(56)
Fair Value Longer than 12 months		4,421
Unrealized Losses Longer than 12 months		(394)
Fair Value Total	7,552	10,070
Unrealized Losses Total	(85)	(450)
Collateralized Corporate Bank Loans [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value 12 months or less	64,712	23,026
Unrealized Losses 12 months or less	(824)	(422)
Fair Value Longer than 12 months	8,898	6,968
Unrealized Losses Longer than 12 months	(1,091)	(67)
Fair Value Total	73,610	29,994
Unrealized Losses Total	(1,915)	(489)
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value 12 months or less	50,546	35,719
Unrealized Losses 12 months or less	(945)	(413)
Fair Value Longer than 12 months	15,684	34,684
Unrealized Losses Longer than 12 months	(656)	(1,562)
Fair Value Total	66,230	70,403
Unrealized Losses Total	(1,601)	(1,975)
Collateralized Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value 12 months or less	20,469	1,383
Unrealized Losses 12 months or less	(365)	(229)
Fair Value Longer than 12 months	2,966	4,840
Unrealized Losses Longer than 12 months	(5)	(278)
Fair Value Total	23,435	6,223
Unrealized Losses Total	$ (370)	$ (507)