Fair Value Measurements And Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2011

Fair Value Measurements And Financial Instruments [Abstract]

Schedule Of Financial Assets Measured At Fair Value On A Recurring Basis

	Balance Sheet Classification	December 31, 2011		Quoted Prices In Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Money-market securities	Cash and cash equivalents	$	745,381	$	745,381	$	—	$	—
Available-for-sale marketable securities	Other current assets		38,657		38,657		—		—
Trading marketable securities	Other assets		204,825		204,825		—		—
Interest rate swap	Other assets		18,078		—		18,078		—
Total assets		$	1,006,941	$	988,863	$	18,078	$	—

	Balance Sheet Classification	January 1, 2011		Quoted Prices In Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Money-market securities	Cash and cash equivalents	$	364,418	$	364,418	$	—	$	—
Trading marketable securities	Other assets		190,438		190,438		—		—
Available-for-sale marketable securities	Other current assets		33,745		33,745		—		—
Total assets		$	588,601	$	588,601	$	—	$	—
Liabilities
Interest rate swap	Other liabilities	$	10,046	$	—	$	10,046	$	—
Total liabilities		$	10,046	$	—	$	10,046	$	—

Schedule Of Financial Assets And Liabilities Measured At Fair Value On Nonrecurring Basis

	December 31, 2011		Quoted Prices In Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Description
Long-lived assets	$	29,234	$	—	$	29,234	$	—
Total assets	$	29,234	$	—	$	29,234	$	—