Exhibit 12.1

STATEMENT RE COMPUTATION OF EARNINGS TO FIXED CHARGES

	Three Months Ended
	March 31,			Year Ended December 31,
(in thousands)	2011			2010			2009			2008			2007			2006
Ratio of Earnings to Fixed Charges
Earnings:
Income before income taxes	$	33,900		$	79,252		$	7,769		$	56,564		$	47,610		$	28,119
Add:
Amortization of capitalized interest		36			36			35			32			19			13
Fixed charges, net of capitalized interest		342			1,749			1,966			2,151			2,060			1,857
Income before income taxes and fixed charges, net	$	34,278		$	81,037		$	9,770		$	58,747		$	49,689		$	29,989
Fixed Charges:
Total interest expense	$	288		$	1,508		$	1,695		$	1,669		$	1,630		$	1,629
Capitalized interest		9			18			75			390			186			149
Interest factor in rents		54			241			271			482			430			228
Total fixed charges	$	351		$	1,767		$	2,041		$	2,541		$	2,246		$	2,006
Ratio of earnings to fixed charges		97.5	x		45.9	x		4.8	x		23.1	x		22.1	x		15.0	x