4. Earnings per Share

We compute earnings per share using the two-class method. The two-class method requires an earnings allocation formula that determines earnings per share for common shareholders and participating security holders according to dividends declared and participating rights in undistributed earnings. We consider time-based restricted stock awards to be participating securities because holders of such shares have non-forfeitable dividend rights. Under the two-class method, undistributed earnings allocated to participating securities are subtracted from net income attributable to the Company in determining net income attributable to common shareholders.

Additionally, in accordance with ASC 480, “Distinguishing Liabilities from Equity”, the increase in the redemption value for the noncontrolling interest of one of our joint ventures reduces income attributable to common shareholders (and a decrease in redemption value increases income attributable to common shareholders).

Basic earnings per common share are computed by dividing net income attributable to common shareholders by the weighted-average common shares outstanding. Diluted earnings per common share are computed by dividing the net income attributable to common shareholders by the diluted weighted average common shares outstanding. Diluted weighted average common shares outstanding consists of basic weighted average common shares outstanding plus weighted average awards outstanding under our equity compensation plans, which are dilutive securities.

The calculations of basic earnings per common share and diluted earnings per common share for the years ended December 31, 2017, December 25, 2016 and December 27, 2015 are as follows (in thousands, except per share data):




	2017		2016		2015

Basic earnings per common share:
Net income attributable to the Company	$	102,292	$	102,820	$	75,682
Change in noncontrolling interest redemption value		1,419		567		65
Net income attributable to participating securities		(423)		(420)		(325)
Net income attributable to common shareholders	$	103,288	$	102,967	$	75,422

Weighted average common shares outstanding		36,083		37,253		39,458
Basic earnings per common share	$	2.86	$	2.76	$	1.91

Diluted earnings per common share:
Net income attributable to common shareholders	$	103,288	$	102,967	$	75,422

Weighted average common shares outstanding		36,083		37,253		39,458
Dilutive effect of outstanding equity awards		439		355		542
Diluted weighted average common shares outstanding		36,522		37,608		40,000
Diluted earnings per common share	$	2.83	$	2.74	$	1.89

Shares subject to options to purchase common stock with an exercise price greater than the average market price for the year were not included in the computation of diluted earnings per common share because the effect would have been antidilutive. The weighted average number of shares subject to antidilutive options was 278,000 in 2017, 331,000 in 2016 and 251,000 in 2015.

See Note 6 for additional information regarding our noncontrolling interests and Note 18 for equity awards, including restricted stock.