Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2021

Stock-Based Compensation [Abstract]

Weighted Average Assumptions Used to Determine Fair Value for Stock Awards

The fair value for stock awards was estimated at the date of grant using the Black-Scholes option valuation model with the following weighted average assumptions for the years ended December 31, 2021, 2020 and 2019:

	Year Ended December 31,
	2021			2020			2019
Expected life (in years)		6.9			6.7			6.6
Interest rate		0.71	%		1.67	%		2.62	%
Volatility		32.04	%		30.34	%		30.26	%
Expected dividend yield		0.31	%		0.35	%		0.37	%

Stock Option Activity

The following table summarizes stock option activity for the year ended December 31, 2021:

	Awards			Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value (Millions)
Awards outstanding at December 31, 2020		1,363,366		$	57.29
Granted		255,769			66.00
Exercised		(251,195	)		51.12
Canceled		(37,938	)		64.92
Awards outstanding at December 31, 2021		1,330,002		$	59.91		6.14		$	18.7
Awards exercisable at December 31, 2021		834,060		$	59.09		4.80		$	12.8

Non-vested Stock Option Activity

Non-vested stock option activity for the year ended December 31, 2021 is as follows:

	Awards			Weighted Average Grant Date Fair Value per Share
Nonvested awards outstanding at December 31, 2020		487,160		$	58.61
Granted		255,769			66.00
Vested		(225,402	)		60.88
Canceled		(21,585	)		61.11
Nonvested awards outstanding at December 31, 2021		495,942		$	61.28

Restricted Stock Activity

The following table summarizes the restricted stock activity for the Plan:

	Awards			Weighted Average Grant Date Fair Value per Share
Unvested balance at December 31, 2020		201,985		$	58.07
Granted		102,309			66.20
Vested		(51,497	)		60.40
Canceled		(56,664	)		60.98
Unvested balance at December 31, 2021		196,133		$	60.87