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