Exhibit 12.1

Ratio of Earnings to Fixed Charges

(In thousands)

	Nine Months Ended September 30,		Years Ended December 31,
	2011		2010		2009		2008			2007		2006
Earnings:
Income (loss) before income taxes	$	258,735	$	437,171	$	201,419	$	(2,256	)	$	179,894	$	173,082
Add: fixed charges		17,602		22,569		24,414		30,439			27,287		5,020
Total earnings	$	276,337	$	459,740	$	225,833	$	28,183		$	207,181	$	178,102
Fixed charges:
Interest expensed	$	12,543	$	16,011	$	16,266	$	20,514		$	18,962	$	608
Amortization of debt issuance cost		987		1,315		2,444		4,313			3,410		508
Interest component of rental payments (1)		4,072		5,243		5,704		5,612			4,915		3,904
Total fixed charges	$	17,602	$	22,569	$	24,414	$	30,439		$	27,287	$	5,020
Ratio of earnings to fixed charges		15.7		20.4		9.3		0.9			7.6		35.5
Total additional earnings required to achieve 1:1 coverage ratio of fixed charges	$	—	$	—	$	—	$	2,089		$	—	$	—

(1) Estimated at 33% of rental expense as a reasonable approximation of the interest factor.