Net Income Per Share and Stockholders' Equity

Net Income Per Share. Basic net income per share is computed by dividing distributed and undistributed net income allocable to common shares by the weighted-average number of common shares outstanding during the applicable period. The basic weighted-average number of common shares outstanding during the period excludes unvested share-based payment awards. Diluted net income per share was calculated under the treasury stock method for the quarters ended March 31, 2018 and March 31, 2017, which in both periods was more dilutive than the two-class method.

The following table sets forth the computation of basic and diluted net income per share for periods presented (in millions of dollars, except share and per share amounts):



	Quarter Ended
	March 31,
	2018		2017
Numerator:
Net income	$	25.7	$	36.0
Denominator – Weighted-average common shares outstanding (in thousands):
Basic	16,707		17,385
Add: dilutive effect of non-vested common shares, restricted stock units and performance shares	324		218
Diluted	17,031		17,603

Net income per common share, Basic:	$	1.54	$	2.07
Net income per common share, Diluted:	$	1.51	$	2.04

The following securities were excluded from the weighted-average diluted shares computation for the periods presented as their inclusion would have been anti-dilutive (in thousands of shares):



	Quarter Ended
	March 31,
	2018	2017
Options to purchase common shares¹	—	2
Non-vested common shares, restricted stock units and performance shares	—	64
Total excluded	—	64

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¹	Related to the 1,543 fully-vested stock options that were outstanding as of March 31, 2017 and subsequently expired on April 2, 2017.

Dividends. During the quarters ended March 31, 2018 and March 31, 2017, we paid a total of approximately $10.0 million and $9.3 million, respectively, in cash dividends to stockholders, including the holders of restricted stock, and in dividend equivalents to the holders of certain restricted stock units and performance shares.

Treasury Stock. From time to time, we repurchase shares pursuant to a stock repurchase program authorized by our Board of Directors. Repurchase transactions will occur at such times and prices as management deems appropriate and will be funded with our excess liquidity after giving consideration to, among other things, internal and external growth opportunities and future cash flows. Repurchases may be in open-market transactions or in privately negotiated transactions and the program may be modified or terminated by our Board of Directors at any time.

Repurchases of our common stock pursuant to the stock repurchase program is recorded as Treasury stock and consisted of the following for each period presented:



	Quarter Ended
	March 31,
	2018		2017
Number of common shares repurchased	58,155		415,346
Weighted-average repurchase price (dollars per share)	$	104.50	$	78.70
Total cost of repurchased common shares (in millions of dollars)	$	6.1	$	32.7

At March 31, 2018, $104.5 million were available to repurchase our common shares pursuant to the stock repurchase program.

Preferred Stock. In connection with a tax asset protection rights plan, our Board of Directors declared a dividend, payable April 22, 2016, of one right for each outstanding share of our common stock. In general, if the rights become exercisable, each right would allow its holder to purchase one one-hundredth of a share of our Series A Preferred Stock. The authorized number of shares of Series A Preferred Stock is 900,000.