Stock-based Compensation (Tables)

9 Months Ended

Sep. 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 September 30,						Nine Months Ended September 30,
(in millions)	2022			2021			2022			2021
Stock-based compensation expense	$	7.7		$	5.8		$	21.8		$	16.8
Tax benefit		(1.7	)		(1.2	)		(4.6	)		(3.5	)
Stock-based compensation expense, net of taxes	$	6.0		$	4.6		$	17.2		$	13.3

Summary of Stock Option Activity

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

	Nine Months Ended September 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		(262,900	)		86.82		(223,426	)		80.46
Forfeited or cancelled		(6,075	)		116.44		(4,769	)		118.01
Outstanding, end of period		1,101,575			107.13		1,232,123			99.07

Summary of Activity Information about Employee Restricted Stock Units

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

	Nine Months Ended September 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		147,438			138.46		171,575			115.44
Vested		(120,715	)		119.29		(116,739	)		111.06
Forfeited		(23,148	)		122.94		(20,846	)		117.18
Outstanding, end of period		383,675			124.77		384,470			117.53
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