Stockholders' Equity

6 Months Ended

Jun. 30, 2017

Equity [Abstract]

Stockholders' Equity

STOCKHOLDERS’ EQUITY

Equity-Based Incentive Plans

Equity-based incentive plans include stock options, restricted stock units (time-based and performance-based) and other stock awards. The number of shares available for grant under these plans as of June 30, 2017 was 8.9 million.

The following table summarizes stock option activity under our equity-based plans for the six months ended June 30, 2017:

	Number of Shares
Balance at December 31, 2016	2,815,224
Granted	—
Exercised	(1,041,720	)
Forfeited	(53,413	)
Expired	—
Balance at June 30, 2017	1,720,091
Exercisable at June 30, 2017	1,320,866

The aggregate intrinsic value of stock options outstanding was $35.1 million and $46.2 million as of June 30, 2017 and December 31, 2016, respectively.

The following table summarizes restricted stock unit (RSU) and performance-based restricted stock unit (PSU) activity under our equity-based plans for the six months ended June 30, 2017:

	RSUs				PSUs
	Number of Units		Weighted-Average Grant Date Fair Value		Number of Units		Weighted-Average Grant Date Fair Value
Nonvested at December 31, 2016	2,323,051		$	20.32	149,412		$	33.51
Granted	966,329		27.88		239,792		28.43
Vested	(549,248	)	19.46		(7,518	)	33.51
Forfeited	(147,674	)	23.25		(18,894	)	33.51
Nonvested at June 30, 2017	2,592,458		$	23.15	362,792		$	30.15

Stock-Based Compensation

Stock-based compensation expense is measured based on the fair value of the stock option on the grant date and recognized over the requisite service period for each separately vesting portion of the stock option award. Stock-based compensation expense and other disclosures for stock-based awards made to our employees pursuant to the equity plans was as follows: 

	Three Months Ended June 30,				Six Months Ended June 30,
(in thousands)	2017		2016		2017		2016
Cost of providing services	$	2,031	$	1,624	$	3,643	$	3,439
Sales and marketing	1,621		1,643		2,923		3,628
General and administrative	2,744		2,644		5,035		5,617
Systems development and programming costs	1,103		597		2,105		1,221
Total stock-based compensation expense	$	7,499	$	6,508	$	13,706	$	13,905
Income tax benefit related to stock-based compensation expense	$	2,682	$	2,248	$	4,808	$	4,828
Tax benefit realized from stock options exercised and similar awards	$	10,525	$	427	$	16,034	$	2,415

Stock Repurchases

The board of directors authorizes repurchases through an ongoing program initiated in May 2014. During the six months ended June 30, 2017, we repurchased 1.1 million shares of common stock for $29.5 million. As of June 30, 2017, $30.5 million remained available for further repurchases of our common stock under our ongoing stock repurchase program.