Earnings Per Share (Tables)

3 Months Ended

Mar. 31, 2013

Earnings Per Share [Abstract]

Earnings per share

		Three months ended March 31,
		2013		2012
Net earnings		$	105,850	$	82,584
Less: net earnings attributable to unvested restricted stock			(1,782)		(1,463)
	Net earnings available to common stock	$	104,068	$	81,121
Weighted-average common shares outstanding			99,056		102,034
Dilutive effect of outstanding options (determined using treasury stock method)			231		159
	Weighted-average common shares and potential common shares outstanding		99,287		102,193
Anti-dilutive stock options not included in treasury stock method computation			47		2,224