Acquisitions (Tables)

9 Months Ended

Sep. 30, 2011

Acquisitions [Abstract]

Summary of pro-forma consolidated financial information

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
(Thousands of dollars except per share data)	2011		2010		2011		2010
Net sales	$	2,484,920	$	2,252,866	$	6,727,098	$	6,208,024
Net income		179,877		171,047		426,710		390,541
Net income per common share:
Basic	$	1.74	$	1.59	$	4.06	$	3.60
Diluted	$	1.71	$	1.56	$	3.97	$	3.54