	For the Three Months Ended September 30,
	2019						2018
	Net Income		Shares		Per Share Amount		Net Income		Shares		Per Share Amount
	(In thousands, except per share amounts)
Basic earnings per share	$	98,028		78,164	$	1.25	$	95,988		86,616	$	1.11
Effect of dilutive incentive-based awards				640						926
Diluted earnings per share	$	98,028		78,804	$	1.24	$	95,988		87,542	$	1.10

	For the Nine Months Ended September 30,
	2019						2018
	Net Income		Shares		Per Share Amount		Net Income		Shares		Per Share Amount
	(In thousands, except per share amounts)
Basic earnings per share	$	113,659		81,003	$	1.40	$	55,841		86,410	$	0.65
Effect of dilutive incentive-based awards				735						619
Diluted earnings per share	$	113,659		81,738	$	1.39	$	55,841		87,029	$	0.64

In accordance with the Earnings Per Share Topic of the ASC, basic earnings per share is computed by dividing net income by the weighted average number of shares of common stock outstanding during the period (excluding treasury stock and unvested restricted stock awards). Unvested restricted stock awards are eligible to receive dividends, if any; however, dividend rights will be forfeited if the award does not vest. Accordingly, only vested shares of formerly restricted stock are included in the calculation of basic earnings per share. The weighted average number of repurchased shares during the period, if any, which are held as treasury stock, are excluded from shares of common stock outstanding.

Diluted earnings per share is determined using the treasury stock method based on the dilutive effect of certain unvested restricted stock awards and shares of common stock that are issuable upon exercise of stock options. During the three and nine months ended September 30, 2019, there were approximately 394,000 and 300,000 anti-dilutive shares of common stock excluded from the computation of diluted earnings per share, respectively. There were no anti-dilutive shares of common stock excluded from the computation of diluted earnings per share during the three months ended September 30, 2018 and for the nine months ended September 30, 2018, there were approximately 1,736,000 anti-dilutive shares of common stock excluded from the computation of diluted earnings per share. The Company’s outstanding performance-vesting restricted awards of approximately 2,085,000 and 1,941,000 as of September 30, 2019 and 2018, respectively, are considered contingently issuable shares and are excluded from the calculation of diluted earnings per share until the performance measure criteria is met as of the end of the reporting period.