Financial Instruments And Investments (Marketable Securities Fair Value And Unrealized Losses) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2014 securities		Dec. 31, 2013 securities
Financial Instruments and Investments [Line Items]
Marketable Securities Fair Value Less than 12 Months	$ 17,423	[1]	$ 32,433	[2]
Marketable Securities Unrealized Losses Less Than 12 Months	(318)	[1]	(971)	[2]
Marketable Securities Fair Value 12 Months or Longer	32,922	[1]	20,970	[2]
Marketable Securities Unrealized Losses 12 Months or Longer	(1,758)	[1]	(1,492)	[2]
Marketable Securities Fair Value Total	50,345	[1]	53,403	[2]
Marketable Securities Unrealized Losses Total	(2,076)	[1]	(2,463)	[2]
Number of securities	119		122
Debt Securities
Financial Instruments and Investments [Line Items]
Marketable Securities Fair Value Less than 12 Months	15,809	[1]	30,128	[2]
Marketable Securities Unrealized Losses Less Than 12 Months	(196)	[1]	(845)	[2]
Marketable Securities Fair Value 12 Months or Longer	32,922	[1]	20,970	[2]
Marketable Securities Unrealized Losses 12 Months or Longer	(1,758)	[1]	(1,492)	[2]
Marketable Securities Fair Value Total	48,731	[1]	51,098	[2]
Marketable Securities Unrealized Losses Total	(1,954)	[1]	(2,337)	[2]
Collateralized Mortgage Backed Securities
Financial Instruments and Investments [Line Items]
Marketable Securities Fair Value Less than 12 Months	4,667	[1]	6,444	[2]
Marketable Securities Unrealized Losses Less Than 12 Months	(28)	[1]	(169)	[2]
Marketable Securities Fair Value 12 Months or Longer	2,457	[1]	1,421	[2]
Marketable Securities Unrealized Losses 12 Months or Longer	(170)	[1]	(119)	[2]
Marketable Securities Fair Value Total	7,124	[1]	7,865	[2]
Marketable Securities Unrealized Losses Total	(198)	[1]	(288)	[2]
U.S. Government Bonds
Financial Instruments and Investments [Line Items]
Marketable Securities Fair Value Less than 12 Months	1,548	[1]	8,114	[2]
Marketable Securities Unrealized Losses Less Than 12 Months	(1)	[1]	(245)	[2]
Marketable Securities Fair Value 12 Months or Longer	16,128	[1]	10,866	[2]
Marketable Securities Unrealized Losses 12 Months or Longer	(893)	[1]	(840)	[2]
Marketable Securities Fair Value Total	17,676	[1]	18,980	[2]
Marketable Securities Unrealized Losses Total	(894)	[1]	(1,085)	[2]
Municipal Bonds
Financial Instruments and Investments [Line Items]
Marketable Securities Fair Value Less than 12 Months	6,860	[1]	12,286	[2]
Marketable Securities Unrealized Losses Less Than 12 Months	(101)	[1]	(335)	[2]
Marketable Securities Fair Value 12 Months or Longer	13,038	[1]	7,782	[2]
Marketable Securities Unrealized Losses 12 Months or Longer	(651)	[1]	(479)	[2]
Marketable Securities Fair Value Total	19,898	[1]	20,068	[2]
Marketable Securities Unrealized Losses Total	(752)	[1]	(814)	[2]
Corporate Debt Securities
Financial Instruments and Investments [Line Items]
Marketable Securities Fair Value Less than 12 Months	2,734	[1]	3,284	[2]
Marketable Securities Unrealized Losses Less Than 12 Months	(66)	[1]	(96)	[2]
Marketable Securities Fair Value 12 Months or Longer	1,299	[1]	901	[2]
Marketable Securities Unrealized Losses 12 Months or Longer	(44)	[1]	(54)	[2]
Marketable Securities Fair Value Total	4,033	[1]	4,185	[2]
Marketable Securities Unrealized Losses Total	(110)	[1]	(150)	[2]
Equity Securities
Financial Instruments and Investments [Line Items]
Marketable Securities Fair Value Less than 12 Months	1,614	[1]	2,305	[2]
Marketable Securities Unrealized Losses Less Than 12 Months	(122)	[1]	(126)	[2]
Marketable Securities Fair Value 12 Months or Longer	0	[1]	0	[2]
Marketable Securities Unrealized Losses 12 Months or Longer	0	[1]	0	[2]
Marketable Securities Fair Value Total	1,614	[1]	2,305	[2]
Marketable Securities Unrealized Losses Total	$ (122)	[1]	$ (126)	[2]

[1] Includes approximately 119 securities.

[2] Includes approximately 122 securities.