Financial Instruments And Investments (Unrecognized Gross Unrealized Gains And The Fair Value) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Financial Instruments and Investments [Line Items]
Available-for-sale Securities, Unrealized Gain Position, Fair Value	$ 175,639	$ 140,096
Available-for-sale Securities, Gross Unrealized Gain	38,940	38,366
Debt Securities
Financial Instruments and Investments [Line Items]
Available-for-sale Securities, Unrealized Gain Position, Fair Value	76,882	40,403
Available-for-sale Securities, Gross Unrealized Gain	2,883	1,274
Collateralized Mortgage Backed Securities
Financial Instruments and Investments [Line Items]
Available-for-sale Securities, Unrealized Gain Position, Fair Value	17,633	9,589
Available-for-sale Securities, Gross Unrealized Gain	621	438
U.S. Government Bonds
Financial Instruments and Investments [Line Items]
Available-for-sale Securities, Unrealized Gain Position, Fair Value	32,557	12,033
Available-for-sale Securities, Gross Unrealized Gain	1,005	136
Municipal Bonds
Financial Instruments and Investments [Line Items]
Available-for-sale Securities, Unrealized Gain Position, Fair Value	10,622	8,671
Available-for-sale Securities, Gross Unrealized Gain	458	332
Corporate Debt Securities
Financial Instruments and Investments [Line Items]
Available-for-sale Securities, Unrealized Gain Position, Fair Value	16,070	10,110
Available-for-sale Securities, Gross Unrealized Gain	799	368
Equity Securities
Financial Instruments and Investments [Line Items]
Available-for-sale Securities, Unrealized Gain Position, Fair Value	68,928	72,636
Available-for-sale Securities, Gross Unrealized Gain	35,675	37,001
Mutual Funds - Equity
Financial Instruments and Investments [Line Items]
Available-for-sale Securities, Unrealized Gain Position, Fair Value	23,764	18,853
Available-for-sale Securities, Gross Unrealized Gain	382	91
Cash and Cash Equivalents
Financial Instruments and Investments [Line Items]
Available-for-sale Securities, Unrealized Gain Position, Fair Value	6,065	8,204
Available-for-sale Securities, Gross Unrealized Gain	$ 0	$ 0