Earnings Per Share (Tables)

6 Months Ended

Jun. 30, 2011

Earnings Per Share [Abstract]

Earnings per share

	Six months ended June 30,						Three months ended June 30,
	2011			2010			2011			2010
Net earnings	$	116,468		$	154,734		$	69,478		$	83,380
Less: net earnings attributable to unvested restricted stock awards and restricted stock units		(1,601	)		(1,679	)		(1,003	)		(927	)
Net earnings available to common stock	$	114,867		$	153,055		$	68,475		$	82,453
Weighted-average common shares outstanding		112,569			113,805			111,389			113,935
Dilutive effect of outstanding options (determined using treasury stock method)		375			322			368			253
Weighted-average common shares and potential common shares outstanding		112,944			114,127			111,757			114,188
Anti-dilutive stock options not included in treasury stock method computation		917			4,392			424			4,680