Earnings Per Share (Tables)

3 Months Ended

Mar. 31, 2012

Earnings Per Share [Abstract]

Computation Of Basic And Diluted Earnings Per Share

	Three Months Ended March 31,
	2012		2011
Net income	$	34,773	$	31,398
Shares for basic and diluted calculations:
Average shares used in basic computation		53,243		52,534
Dilutive effect of stock options and units (1)		9,426		10,645
Average shares used in diluted computation		62,669		63,179
Net income per share:
Basic	$	0.65	$	0.60
Diluted (1)	$	0.55	$	0.50

⁽¹⁾Diluted earnings per share is computed on the basis of the weighted average number of shares of common stock plus the effect of dilutive potential common shares outstanding during the period using the treasury stock method. Diluted earnings per share include stock options and units.