16. Earnings per share

The following table presents the calculation of basic and diluted net income per share:

	Years ended December 31,
(in thousands, except share and per share data)	2017		2016			2015
Numerator:
Net income from continuing operations	$	82,594	$	62,524		$	91,416
Interest expense, net of tax		2,606		3,255			3,019
Amortization of debt issuance costs, net of tax		681		781			868
Net income, adjusted from continuing operations		85,881		66,560			95,303
Net loss from discontinued operations		-		(10,748	)		(28,546	)
Net income, adjusted	$	85,881	$	55,812		$	66,757

Denominator:
Weighted-average number of shares-basic		41,816,431		40,184,159			38,595,435
Dilutive securities-equity awards		1,115,244		1,054,453			939,882
Dilutive securities-convertible debt		7,396,262		8,096,500			7,720,525
Weighted-average number of shares-diluted		50,327,937		49,335,112			47,255,842

Net income per share-basic from continuing operations	$	1.98	$	1.56		$	2.37
Net loss per share-basic from discontinued operations		-		(0.27	)		(0.74	)
Net income per share-basic	$	1.98	$	1.29		$	1.63

Net income per share-diluted from continuing operations	$	1.71	$	1.35		$	2.02
Net loss per share-diluted from discontinued operations		-		(0.22	)		(0.61	)
Net income per share-diluted	$	1.71	$	1.13		$	1.41

For the year ending December 31, 2017 and 2016, substantially all of the outstanding stock options to purchase shares of common stock were included in the calculation of diluted earnings per share. For the years ending December 31, 2015, outstanding stock options to purchase approximately 1.4 million shares of common stock, respectively, are not considered in the diluted earnings per share calculation because the exercise price of these options is greater than the average per share closing price during the year and their effect would be anti-dilutive.