Share-Based Compensation Plans (Tables)

9 Months Ended

Sep. 30, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Costs Associated with Share-Based Compensation Plans

The following table presents costs associated with the Company’s share-based compensation plans:

	Three Months Ended September 30,				Nine Months Ended September 30,
(in thousands)	2018		2017		2018		2017
Expense:
RSUs	$	6,392	$	5,865	$	31,570	$	28,634
Stock options		—		69		—		203
Employee stock purchase plan		849		682		2,806		2,359
	$	7,241	$	6,616	$	34,376	$	31,196

Summary of RSU Activity

The following table summarizes RSU activity for the nine months ended September 30, 2018:

(in thousands, except weighted-average grant-date fair value)	Shares			Weighted-average grant-date fair value
Unvested at December 31, 2017		1,411		$	36.66
Granted during 2018		741		$	55.65
Vested during 2018		(869	)	$	41.34
Forfeited during 2018		(34	)	$	44.93
Unvested at September 30, 2018		1,249		$	44.43