Share-Based Compensation Plans (Tables)

6 Months Ended

Jun. 30, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Costs Associated with Share-Based Compensation Plans

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

	Three Months Ended June 30,				Six Months Ended June 30,
(in thousands)	2018		2017		2018		2017
Expense:
RSUs	$	6,652	$	6,754	$	25,178	$	22,769
Stock options		—		67		—		134
Employee stock purchase plan		974		726		1,957		1,677
	$	7,626	$	7,547	$	27,135	$	24,580

Summary of RSU Activity

The following table summarizes RSU activity for the six months ended June 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		699		$	56.13
Vested during 2018		(805	)	$	41.20
Forfeited during 2018		(10	)	$	44.16
Unvested at June 30, 2018		1,295		$	44.28