Fair Value Measurements (Summary Of Available-For-Sale Securities) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Cash and cash equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		$ 73,390
Gross Unrealized Gains		0
Gross Unrealized (Losses)		0
Fair Value		73,390
Restricted cash and cash equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		770,000
Gross Unrealized Gains		0
Gross Unrealized (Losses)		0
Fair Value		770,000
Short-term available for sale securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,546
Gross Unrealized Gains	0
Gross Unrealized (Losses)	0
Fair Value	3,546
Long-term available-for-sale securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,766	1,766
Gross Unrealized Gains	818	1,213
Gross Unrealized (Losses)	0	0
Fair Value	2,584	2,979
Money market funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		843,390
Gross Unrealized Gains		0
Gross Unrealized (Losses)		0
Fair Value		843,390
Guaranteed investment certificates original maturities of three months or more [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,727
Gross Unrealized Gains	0
Gross Unrealized (Losses)	0
Fair Value	2,727
Equity securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	819	1,766
Gross Unrealized Gains	0	1,213
Gross Unrealized (Losses)	0	0
Fair Value	819	2,979
Equity securities [Member] | Long-term Debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,766
Gross Unrealized Gains	818
Gross Unrealized (Losses)	0
Fair Value	$ 2,584