Earnings Per Share (Tables)

9 Months Ended

Sep. 30, 2013

Earnings Per Share [Abstract]

Earnings per share

				Nine months ended September 30,				Three months ended September 30,
				2013		2012		2013		2012
Net earnings				$	292,187	$	283,139	$	98,175	$	107,062
Less: net earnings attributable to unvested restricted stock					(4,754)		(5,150)		(1,527)		(1,912)
		Net earnings available to common stock		$	287,433	$	277,989	$	96,648	$	105,150
Weighted-average common shares outstanding					98,881		100,340		98,723		99,424
Dilutive effect of outstanding securities (determined using
	treasury stock method)				254		261		270		276
		Weighted-average common shares and potential
			common shares outstanding		99,135		100,601		98,993		99,700
Anti-dilutive securities not included in treasury stock
	method computation				89		717		131		461