Fair Value Measurements (Schedule Of Assets And Liabilities Carried At Fair Value Measured On A Recurring Basis) (Details) (Fair Value, Measurements, Recurring [Member], USD $) In Thousands, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 406,668	[1]	$ 439,813	[1]
Restricted cash	6,988	[2]	6,934	[2]
Total	413,656		446,747
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	[1]	0	[1]
Restricted cash	0	[2]	0	[2]
Total	0		0
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	[1]	0	[1]
Restricted cash	0	[2]	0	[2]
Total	0		0
Portion at Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	406,668	[1]	439,813	[1]
Restricted cash	6,988	[2]	6,934	[2]
Total	413,656		446,747
Money Market Funds [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 147,900		$ 147,700

[1] Cash and cash equivalents include money market funds with original maturity dates of three months or less, which are Level 1 assets. At March 31, 2014 and December 31, 2013, we had $147.9 million and $147.7 million, respectively, in money market funds.

[2] Restricted cash is classified as “Prepaid expenses and other” in our Condensed Consolidated Balance Sheets.