Earnings Per Share

12 Months Ended

Dec. 31, 2012

Earnings Per Share [Abstract]

Earnings Per Share

(12) Earnings Per Share

The following table presents the components of basic and diluted earnings per share for the years ended December 31, 2012, 2011 and 2010 (in thousands, except per share amounts):

	2012			2011			2010
Net earnings attributable to Kirby	$	209,438		$	183,026		$	116,249
Undistributed earnings allocated to restricted shares		(1,618	)		(1,613	)		(1,125	)
Income available to Kirby common stockholders — basic		207,820			181,413			115,124
Undistributed earnings allocated to restricted shares		1,618			1,613			1,125
Undistributed earnings reallocated to restricted shares		(1,612	)		(1,606	)		(1,122	)
Income available to Kirby common stockholders — diluted	$	207,826		$	181,420		$	115,127
Shares outstanding:
Weighted average common stock issued and outstanding		55,897			54,673			53,852
Weighted average unvested restricted stock		(431	)		(482	)		(521	)
Weighted average common stock outstanding — basic		55,466			54,191			53,331
Dilutive effect of stock options		208			222			135
Weighted average common stock outstanding — diluted		55,674			54,413			53,466
Net earnings per share attributable to Kirby common stockholders:
Basic	$	3.75		$	3.35		$	2.16
Diluted	$	3.73		$	3.33		$	2.15

Certain outstanding options to purchase approximately 100,000, 2,000 and 114,000 shares of common stock were excluded in the computation of diluted earnings per share as of December 31, 2012, 2011 and 2010, respectively, as such stock options would have been antidilutive.