Fair Value Measurements (Schedule Of Assets And Liabilities Carried At Fair Value Measured On A Recurring Basis) (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash equivalents		$ 486,831	$ 432,056
Restricted cash		4,232	6,474
Deferred compensation plan assets		7,497	3,139
Total		498,560	441,669
Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash equivalents	[1]	486,831	432,056
Restricted cash	[2]	4,232	6,474
Deferred compensation plan assets	[3]	7,497	3,139
Total		498,560	441,669
Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash equivalents	[1]	0	0
Restricted cash	[2]	0	0
Deferred compensation plan assets	[3]	0	0
Total		0	0
Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash equivalents	[1]	0	0
Restricted cash	[2]	0	0
Deferred compensation plan assets	[3]	0	0
Total		0	0
Money Market Funds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash equivalents		$ 151,400	$ 156,700

[1] Cash and cash equivalents consist primarily of money market funds with original maturity dates of three months or less, which are Level 1 assets. At December 31, 2015 and 2014, we had $151.4 million and $156.7 million, respectively, in money market funds.

[2] Restricted cash is classified as “Prepaid expenses and other” in our consolidated balance sheets.

[3] Deferred compensation plan assets are classified as “Other assets” in our consolidated balance sheets.