Earnings Per Share

12 Months Ended

Dec. 31, 2011

Earnings Per Share [Abstract]

Earnings Per Share

11. Earnings per Share

Total outstanding shares as of December 31, 2011 and 2010 were 55.5 million and 54.9 million, respectively. The calculation of basic earnings per common share is based on the weighted average number of common shares outstanding in the year, or period, over which they were outstanding. The Company's calculation of diluted earnings per common share assumes that any common shares outstanding were increased by shares that would be issued upon exercise of those stock units for which the average market price for the period exceeds the exercise price; less, the shares that could have been purchased by the Company with the related proceeds, including compensation expense measured but not yet recognized, net of tax.

(in millions)	2011		2010		2009
Weighted average number of common shares outstanding—basic		55.2		54.8		54.5
Employee stock options		0.1		0.1		—
Stock-settled stock appreciation rights		1.7		2.1		1.7
Restricted stock units		0.6		0.2		0.1
Adjusted weighted-average shares and assumed conversions—diluted		57.6		57.2		56.3

Awards of shares representing approximately 4.3 million, 4.1 million and 4.3 million as of December 31, 2011, 2010 and 2009, respectively, of potentially dilutive shares of common stock were outstanding and are not included in the computation of dilutive earnings per share as their effect would have been anti-dilutive because their exercise prices were higher than the average market price during the period.