Stock-based Compensation (Tables)

6 Months Ended

Jun. 30, 2022

Share-Based Payment Arrangement [Abstract]

Compensation Cost and Related Tax Benefits

Compensation cost for the Company’s stock-based awards and the related tax benefits were as follows:

	Three Months Ended June 30,						Six Months Ended June 30,
(in millions)	2022			2021			2022			2021
Stock-based compensation expense	$	7.4		$	5.4		$	14.1		$	11.0
Tax benefit		(1.5	)		(1.1	)		(2.9	)		(2.3	)
Stock-based compensation expense, net of taxes	$	5.9		$	4.3		$	11.2		$	8.7

Summary of Stock Option Activity

Information on the Company’s stock option activity for the six months ended June 30, 2022 and 2021 is summarized below.

	Six Months Ended June 30,
	2022					2021
(in whole shares and dollars)	Shares			Weighted Average Exercise Price		Shares			Weighted Average Exercise Price
Outstanding, beginning of period		1,230,211		$	99.14		1,282,278		$	93.64
Granted		140,339			139.51		178,040			115.35
Exercised		(261,326	)		86.68		(155,584	)		82.43
Forfeited or cancelled		(6,075	)		116.44		(4,769	)		118.01
Outstanding, end of period		1,103,149			107.13		1,299,965			97.87

Summary of Activity Information about Employee Restricted Stock Units

The following tables summarize activity information about employee restricted stock units:

	Six Months Ended June 30,
	2022					2021
(in whole shares and dollars)	Shares			Weighted Average Grant Date Fair Value		Shares			Weighted Average Grant Date Fair Value
Time-based restricted stock units:
Outstanding, beginning of period		380,100		$	117.60		350,480		$	116.37
Granted		147,286			138.48		170,473			115.32
Vested		(118,182	)		119.26		(114,274	)		110.81
Forfeited		(15,868	)		121.56		(15,765	)		117.01
Outstanding, end of period		393,336			124.76		390,914			117.52
Performance-based and market-based restricted stock units:
Outstanding, beginning of period		113,848		$	115.92		97,043		$	119.59
Granted		47,954			140.36		62,143			114.66
Vested		(39,338	)		124.42		(43,506	)		122.27
Forfeited		(3,301	)		120.66		(1,832	)		116.90
Outstanding, end of period		119,163			122.81		113,848			115.92