Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2011

Fair Value Measurements [Abstract]

Summary of financial assets and liabilities measured at fair value on recurring basis

			Fair Value Measurements at Reporting Date Using
	June 30,
	2011		Level 1		Level 2		Level 3
Short-term investments	$	164,161	$	164,161		—		—
Intangible and other long-term assets
Non-qualified deferred compensation assets	$	11,218	$	812	$	10,406		—
Interest rate swap	$	902		—	$	902		—
Accounts Payable
Non-qualified deferred compensation liabilities	$	2,790	$	—	$	2,790		—
Other long-term liabilities
Non-qualified deferred compensation liabilities	$	15,222		—	$	15,222		—

	December 31,
	2010		Level 1		Level 2		Level 3
Intangible and other long-term assets
Non-qualified deferred compensation assets	$	10,820	$	812	$	10,008		—
Interest rate swap	$	161		—	$	161		—
Accounts Payable
Non-qualified deferred compensation liabilities	$	2,953	$	1,429	$	1,524		—
Other long-term liabilities
Non-qualified deferred compensation liabilities	$	14,236		—	$	14,236		—