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


	Three months ended						Nine months ended
	September 30,						September 30,
	2012			2011			2012			2011
Numerator for basic and diluted earnings per share:
Net income	$	23,898		$	36,911		$	86,106		$	97,019
Effect of reallocating undistributed earnings of participating securities		(122	)		(212	)		(458	)		(562	)

Net income available under the two-class method	$	23,776		$	36,699		$	85,648		$	96,457

Denominator:
Denominator for basic earnings per share—weighted-average shares		22,963,318			23,026,741			22,966,134			23,022,836
Effect of dilutive securities:
Employee stock options		—			1,351			833			1,333

Dilutive potential common shares		—			1,351			833			1,333

Denominator for diluted earnings per share—adjusted weighted-average shares		22,963,318			23,028,092			22,966,967			23,024,169

Basic earnings per share	$	1.04		$	1.59		$	3.73		$	4.19

Diluted earnings per share	$	1.04		$	1.59		$	3.73		$	4.19