Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2020

Share-based Payment Arrangement [Abstract]

Stock-Based Compensation Expense and Related Tax Benefit

Total stock-based compensation expense and the related tax benefit were as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
In thousands	2020		2019		2020		2019
Stock options	$	526	$	443	$	993	$	1,024
Restricted stock units	6,367		5,977		14,176		12,444
Unrestricted stock awards	206		158		412		315
Phantom stock units	1,060		525		1,493		1,443
Total stock-based compensation	$	8,159	$	7,103	$	17,074	$	15,226
Related tax benefit	$	1,420	$	1,275	$	3,187	$	2,718

Employee Stock Options Activity

A summary of our stock option activity is as follows:

	Shares	Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Life	Aggregate Intrinsic Value		Weighted Average Grant Date Fair Value
	(in thousands)			(years)	(in thousands)
Outstanding, January 1, 2019	895	$	47.93	6.2	$	4,806
Exercised	(59)	40.57			1,057
Forfeited	(8)	67.38
Expired	(9)	66.36
Outstanding, June 30, 2019	819	$	48.06	5.8	$	12,958
Outstanding, January 1, 2020	458	$	56.38	7.0	$	12,641
Granted	73	87.27					$	26.72
Exercised	(47)	51.52			1,131
Outstanding, June 30, 2020	484	$	61.48	7.3	$	4,871
Exercisable, June 30, 2020	292	$	50.30	6.1	$	4,823

Stock Options, Valuation Assumptions

The weighted average assumptions used to estimate the fair value of stock options granted and the resulting weighted average fair value are as follows:

	Six Months Ended June 30,
	2020		2019
Expected volatility	31.0	%	—	%
Risk-free interest rate	1.4	%	—	%
Expected term (years)	5.3		N/A

Restricted Stock Units Award Activity

The following table summarizes restricted stock unit activity:

In thousands, except fair value	Number of Restricted Stock Units	Weighted Average Grant Date Fair Value		Aggregate Intrinsic Value
Outstanding, January 1, 2019	817
Granted	118	$	56.40
Released (1)	(363)			$	22,304
Forfeited	(36)
Outstanding, June 30, 2019	536
Outstanding, January 1, 2020	684	$	64.38
Granted	189	85.97
Released (1)	(230)	65.14		$	2,506
Forfeited	(13)	66.91
Outstanding, June 30, 2020	630	70.74
Vested but not released, June 30, 2020	8			$	534

⁽¹⁾  Shares released is presented gross of shares netted for employee payroll tax obligations.

Restricted Stock Units, Valuation Assumptions

The weighted average assumptions used to estimate the fair value of performance-based restricted stock units granted with a service and market condition and the resulting weighted average fair value are as follows:

	Six Months Ended June 30,
	2020			2019
Expected volatility	37.6		%	31.3		%
Risk-free interest rate	1.5		%	2.5		%
Expected term (years)	1.8			1.6
Weighted average fair value	$	94.28		$	60.91