Investments (Tables)

9 Months Ended

Sep. 30, 2011

Investments [Abstract]

Investments

	Cost Basis		Unrealized Gain (Loss)			Fair Value
As of September 30, 2011
Short-term investments:
Certificates of deposit	$	199,908	$	—		$	199,908
U.S. dollar indexed bond funds		13,480		2,008			15,488
	$	213,388	$	2,008		$	215,396
Long-term investments:
Assets held in a rabbi trust	$	7,582	$	(782	)	$	6,800
As of December 31, 2010
Short-term investments:
Certificates of deposit	$	221,706	$	—		$	221,706
U.S. dollar indexed bond funds		52,714		(1,297	)		51,417
	$	274,420	$	(1,297	)	$	273,123
Long-term investments:
Assets held in a rabbi trust	$	8,068	$	95		$	8,163