Stockholders' Equity

12 Months Ended

Dec. 31, 2017

Stockholders’ Equity

The following table summarizes the share activity for Holdings:



	For the Year Ended December 31,
	2015	2016	2017
	(in thousands)
Restricted stock granted	1,385	1,426	1,598
Common stock issued through stock option exercise	183	202	227
Unvested restricted stock forfeitures	304	82	27
Stock repurchases for satisfaction of tax obligations	183	232	280

Holdings’ board of directors has authorized a common stock repurchase program to repurchase up to $500.0 million worth of shares of its common stock. The program has been extended until December 31, 2018, and will remain in effect until then, unless further extended or earlier terminated by the board of directors. Stock repurchases under this program may be made in the open market or through privately negotiated transactions, and at times and in such amounts as Holdings deems appropriate. Holdings is funding this program with cash on hand and borrowings under the Select revolving facility.

For the year ended December 31, 2015, Holdings repurchased 1,032,334 shares at a cost of $13.6 million, which includes transaction costs. Holdings did not repurchase shares during the years ended December 31, 2016 and 2017. The common stock repurchase program has available capacity of $185.2 million as of December 31, 2017.