Earnings Per Common Share (Tables)

9 Months Ended

Sep. 30, 2013

Earnings Per Share [Abstract]

Schedule of Basic and Diluted Earnings Per Common Share

The following table sets forth the computation of basic and diluted earnings per common share:

	Three Months Ended September 30,					Nine Months Ended September 30,
	2013			2012		2013			2012
(Dollars in millions, except share amounts, in thousands, and per share amounts)
Net income attributable to Koppers	$	19.1		$	16.0	$	44.5		$	52.0
Less: loss from discontinued operations		(0.1	)		0.0		(0.1	)		(0.1	)
Income from continuing operations attributable to Koppers	$	19.2		$	16.0	$	44.6		$	52.1
Weighted average common shares outstanding:
Basic		20,577			20,694		20,657			20,709
Effect of dilutive securities		224			206		230			231
Diluted		20,801			20,900		20,887			20,940
Earnings per common share – continuing operations:
Basic earnings per common share	$	0.93		$	0.77	$	2.16		$	2.52
Diluted earnings per common share		0.92			0.77		2.13			2.50
Other data:
Antidilutive securities excluded from computation of diluted earnings per common share		254			203		236			191