Debt Obligations (Tables)

12 Months Ended

Dec. 31, 2011

Debt Obligations [Abstract]

Proceeds Upon Issuance Of Senior Convertible Notes

	May 10, 2011
Principal value senior convertible notes	$	700,000
Less issuance cost		(15,750	)
Net proceeds, senior convertible notes	$	684,250
Amounts recognized at issuance:
Senior convertible notes	$	270,004
Common stock, net		262,367
Long-term deferred tax liability		161,043
Issuance costs allocated to senior convertible notes		(6,087	)
Long-term deferred tax asset		(3,624	)
Contingent interest derivative liability		547
Net proceeds, senior convertible notes	$	684,250

Components Of Senior Convertible Notes

	December 31, 2011
Carrying amount of Senior Convertible Notes	$	272,172
Unamortized debt discount		427,828
Principal amount	$	700,000
Carrying amount of equity component, net	$	262,367
Conversion rate (shares of common stock per $1,000 principal amount of notes)		25.3139
Conversion price (per share of common stock)	$	39.50

Components Of Interest Expense For Senior Convertible Notes

	Year Ended
	December 31, 2011
Contractual interest	$	11,740
Amortization of debt discount		2,168
Decrease in contingent interest derivative liability		(69	)
Amortization of issuance costs		31
Total	$	13,870