Earnings Per Share

12 Months Ended

Dec. 31, 2014

Earnings Per Share [Abstract]

Earnings Per Share

Earnings per Share

The Company has unvested shares of restricted stock and restricted stock units outstanding that are considered participating securities and, therefore, computes basic and diluted earnings per share under the two-class method. Basic earnings per share for the periods are based upon the weighted average number of shares of common stock outstanding during the periods. Diluted earnings per share include the effect of certain stock options.

	Year Ended December 31,
	2014			2013			2012
Net income attributable to Westlake Chemical Corporation	$	678,523		$	610,425		$	385,555
Less:
Net income attributable to participating securities	(1,502		)	(2,562		)	(2,160		)
Net income attributable to common shareholders	$	677,021		$	607,863		$	383,395

The following table reconciles the denominator for the basic and diluted earnings per share computations shown in the consolidated statements of operations:

	Year Ended December 31,
	2014		2013		2012
Weighted average common shares—basic (1)	133,111,230		133,224,256		132,578,858
Plus incremental shares from:
Assumed exercise of options (1)	532,184		554,994		704,132
Weighted average common shares—diluted (1)	133,643,414		133,779,250		133,282,990
Earnings per common share attributable to    Westlake Chemical Corporation: (1)
Basic	$	5.09	$	4.57	$	2.89
Diluted	$	5.07	$	4.55	$	2.88

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(1) Share amounts and per share data for the years ended December 31,2013 and 2012 have been restated to reflect the effect of a two-for-one stock split on March 18, 2014. See Note 8 for additional information.

Excluded from the computation of diluted earnings per share for the years ended December 31, 2014, 2013 and 2012 are options to purchase 126,091, 119,452 and 198,024 shares of common stock, respectively. These options were outstanding during the periods reported but were excluded because the effect of including them would have been antidilutive.