The following table sets forth the computation of basic and diluted earnings per share under the two-class method:


	2011			2010			2009
Numerator for basic and diluted earnings per share:
Net income	$	130,136		$	78,716		$	52,810
Effect of reallocating undistributed earnings of participating securities		(749	)		(485	)		(304	)

Net income available under the two-class method	$	129,387		$	78,231		$	52,506

Denominator:
Denominator for basic earnings per share—weighted-average shares		23,011,087			22,969,360			23,097,105
Effect of dilutive securities:
Employee stock options (See Note 8)		1,332			3,802			8,723
Deferred stock awards (See Note 8)		—			4,034			5,864

Dilutive potential common shares		1,332			7,836			14,587

Denominator for diluted earnings per share—adjusted weighted-average shares		23,012,419			22,977,196			23,111,692

Basic earnings per share	$	5.62		$	3.41		$	2.27

Diluted earnings per share	$	5.62		$	3.40		$	2.27