Financial Instruments (Fair Value Of Investments) (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Marketable investment securities available for sale in an unrealized loss position
In Loss Position for Less Than 12 Months, Fair Value	$ 74,407	$ 45,084
In Loss Position for Less Than 12 Months, Gross Unrealized Losses	60	35
In Loss Position for More Than 12 Months, Fair Value	5,732	0
In Loss Position for More Than 12 Months, Gross Unrealized Losses	0	0
Total, Fair Value	80,139	45,084
Total, Gross Unrealized Losses	60	35
Corp
Marketable investment securities available for sale in an unrealized loss position
In Loss Position for Less Than 12 Months, Fair Value	74,407	37,974
In Loss Position for Less Than 12 Months, Gross Unrealized Losses	56	31
In Loss Position for More Than 12 Months, Fair Value	5,732	0
In Loss Position for More Than 12 Months, Gross Unrealized Losses	4	0
Total, Fair Value	80,139	37,974
Total, Gross Unrealized Losses	60	31
Gov Agency
Marketable investment securities available for sale in an unrealized loss position
In Loss Position for Less Than 12 Months, Fair Value	0	7,110
In Loss Position for Less Than 12 Months, Gross Unrealized Losses	0	4
In Loss Position for More Than 12 Months, Fair Value	0	0
In Loss Position for More Than 12 Months, Gross Unrealized Losses	0	0
Total, Fair Value	0	7,110
Total, Gross Unrealized Losses	$ 0	$ 4