Earnings Per Share (Tables)

6 Months Ended

Jun. 30, 2011

Earnings Per Share [Abstract]

Earnings Per Share

	Three Months Ended June 30,						Six Months Ended June 30,
	2011			2010			2011			2010
Numerator:
Net income	$	69,007		$	63,522		$	133,781		$	123,655
Earnings allocated to participating securities		(559	)		(434	)		(1,020	)		(767	)
Numerator for basic earnings per share – income available to common shareholders		68,448			63,088			132,761			122,888
Effect of reallocating undistributed earnings of participating securities		2			1			3			2
Numerator for diluted earnings per share – income available to common shareholders	$	68,450		$	63,089		$	132,764		$	122,890
Denominator:
Weighted average shares outstanding		68,451,428			68,069,864			68,419,699			68,018,225
Less:  Participating securities included in weighted average shares outstanding		(552,945	)		(464,057	)		(519,420	)		(418,876	)
Denominator for basic earnings per common share		67,898,483			67,605,807			67,900,279			67,599,349
Dilutive effect of employee stock compensation plans1		271,002			274,780			272,903			236,257
Denominator for diluted earnings per common share		68,169,485			67,880,587			68,173,182			67,835,606
Basic earnings per share	$	1.01		$	0.93		$	1.96		$	1.82
Diluted earnings per share	$	1.00		$	0.93		$	1.95		$	1.81
1Excludes employee stock options with exercise prices greater than current market price.		785,686			601,361			771,343			1,018,503