Fair-Value Measurements (Summary Of Valuation Of Financial Instruments At Fair-Value) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Assets Measured on Recurring Basis [Line Items]
Cash equivalents	$ 385,548	$ 441,199
Marketable securities	8,285
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets Measured on Recurring Basis [Line Items]
Cash equivalents	63,092	99,092
Marketable securities	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets Measured on Recurring Basis [Line Items]
Cash equivalents	322,456	342,107
Marketable securities	8,285
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis [Line Items]
Cash equivalents	0	0
Marketable securities	$ 0