PER SHARE INFORMATION:

The amounts used to compute the basic and diluted earnings per share attributable to common stock for the years ended December 31, 2017, 2016 and 2015 are illustrated below (in thousands):



	Year Ended December 31,
	2017		2016			2015
Amounts attributable to common stock:
Net income from continuing operations	$	314,978	$	198,725		$	120,286
Net income (loss) from discontinued operations	—		(342		)	190,621
Net income attributable to common stock	$	314,978	$	198,383		$	310,907
Weighted average shares:
Weighted average shares outstanding for basic earnings per share attributable to common stock	156,124		157,287			195,113
Effect of dilutive unvested non-participating stock-based awards	1,031		1			7
Weighted average shares outstanding for diluted earnings per share attributable to common stock	157,155		157,288			195,120

For purposes of calculating diluted earnings per share attributable to common stock, there were no adjustments required to derive Quanta’s net income attributable to common stock. Exchangeable shares that were issued pursuant to certain of Quanta’s historical acquisitions (as further discussed in Note 11), which are exchangeable on a one-for-one basis with shares of Quanta common stock, have been included in the calculation of weighted average shares outstanding for basic and diluted earnings per share attributable to common stock for the portion of the periods that they were outstanding. Additionally, unvested stock-based awards that contain non-forfeitable rights to dividends or dividend equivalents (participating) have been included in the calculation of basic and diluted earnings per share attributable to common stock for the portion of the periods that they were outstanding. Diluted earnings per share attributable to common stock is computed using the weighted average number of common shares outstanding during the period adjusted for all potentially dilutive common stock equivalents, except in cases where the effect of the common stock equivalents would be antidilutive.