Net Income Per Common Share (Tables)

6 Months Ended

Jun. 30, 2014

Earnings Per Share [Abstract]

Computation of net income per common share

(Thousands of dollars except per share data)	Three Months Ended June 30,						Six Months Ended June 30,
	2014			2013			2014			2013
Basic
Average common shares outstanding	96,599,869			101,665,737			97,716,539			101,813,398
Net income	$	291,447		$	257,287		$	406,904		$	373,472
Less net income allocated to unvested restricted shares	(1,722		)	(1,639		)	(2,245		)	(2,278		)
Net income allocated to common shares	$	289,725		$	255,648		$	404,659		$	371,194
Basic net income per common share	$	3.00		$	2.51		$	4.14		$	3.65
Diluted
Average common shares outstanding	96,599,869			101,665,737			97,716,539			101,813,398
Stock options and other contingently issuable shares (1)	1,942,040			2,231,043			1,972,018			2,218,320
Average common shares outstanding assuming dilution	98,541,909			103,896,780			99,688,557			104,031,718
Net income	$	291,447		$	257,287		$	406,904		$	373,472
Less net income allocated to unvested restricted shares
assuming dilution	(1,690		)	(1,607		)	(2,205		)	(2,235		)
Net income allocated to common shares assuming
dilution	$	289,757		$	255,680		$	404,699		$	371,237
Diluted net income per common share	$	2.94		$	2.46		$	4.06		$	3.57

⁽¹⁾  There were no options excluded due to their anti-dilutive effect for the three months ended June 30, 2014. Stock options and other contingently issuable shares excluded 2,932 shares for the six months ended June 30, 2014. There were no options excluded due to their anti-dilutive effect for the three and six months ended June 30, 2013.