Earnings Per Share

Basic and diluted earnings per share were calculated as follows (in thousands, except per share amounts):



	Years Ended November 30,
	2018			2017			2016
Numerator:
Net income	$	170,365		$	180,595		$	105,615
Less: Distributed earnings allocated to nonvested restricted stock	(51		)	(56		)	(45		)
Less: Undistributed earnings allocated to nonvested restricted stock	(927		)	(1,121		)	(508		)
Numerator for basic earnings per share	169,387			179,418			105,062
Effect of dilutive securities:
Interest expense and amortization of debt issuance costs associated with convertible senior notes, net of taxes	3,190			2,654			2,667
Add: Undistributed earnings allocated to nonvested restricted stock	927			1,121			508
Less: Undistributed earnings reallocated to nonvested restricted stock	(805		)	(979		)	(453		)
Numerator for diluted earnings per share	$	172,699		$	182,214		$	107,784
Denominator:
Weighted average shares outstanding — basic	87,773			85,842			85,706
Effect of dilutive securities:
Share-based payments	4,884			4,072			2,170
Convertible senior notes	8,402			8,402			8,402
Weighted average shares outstanding — diluted	101,059			98,316			96,278
Basic earnings per share	$	1.93		$	2.09		$	1.23
Diluted earnings per share	$	1.71		$	1.85		$	1.12

As discussed in Note 13 – Notes Payable, in 2013, we issued the 1.375% Convertible Senior Notes due 2019 that, from issuance, have been convertible into shares of our common stock at a conversion rate of 36.5297 shares for each $1,000 principal amount of the notes. Outstanding stock options to purchase .8 million, 1.6 million and 7.3 million shares of common stock were excluded from the diluted earnings per share calculations for 2018, 2017 and 2016, respectively, because the effect of their inclusion in each case would be antidilutive. In 2017, the decrease in anti-dilutive shares and the increase in dilutive shares, each as compared to 2016, were primarily the result of a year-over-year increase in the average price of our common stock. Contingently issuable shares associated with outstanding PSUs were not included in the basic earnings per share calculations for the periods presented, as the applicable vesting conditions had not been satisfied.