Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2012

Significant Accounting Policies (Tables) [Abstract]

Changes in goodwill

The following table summarizes the changes in goodwill for the years ended December 31, 2012 and 2011:

	Year Ended December 31,
In thousands	2012		2011
Beginning of year balance	$	1,236,318	$	1,232,418
Goodwill related to the Riley Ridge acquisition	—		3,900
Goodwill related to the Thompson Field acquisition	47,272		—
End of year balance	$	1,283,590	$	1,236,318

Weighted average shares used in the basic and diluted net income per common share

The following is a reconciliation of the weighted average shares used in the basic and diluted net income per common share calculations for the periods indicated:

	Year Ended December 31,
In thousands	2012	2011	2010
Basic weighted average common shares	385,205	396,023	370,876
Potentially dilutive securities:
Stock options and SARs	2,584	3,539	3,844
Performance equity awards	86	38	319
Restricted stock	1,063	1,358	1,216
Diluted weighted average common shares	388,938	400,958	376,255

Anti-dilutive securites excluded from computation of diluted net earnings per share

The following securities could potentially dilute earnings per share in the future but were not included in the computation of diluted net income per share, as their effect would have been antidilutive:

	Year Ended December 31,
In thousands	2012	2011	2010
Stock options and SARs	4,068	5,017	3,671
Restricted stock	47	104	17