Stock Based Compensation (Tables)

9 Months Ended

Sep. 30, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Option Activity

The following tables summarize option activity for the nine-month periods ended September 30, 2020 and 2019:

						Weighted
				Weighted		Average		Aggregate
	Number of			Average		Remaining		Intrinsic
	Options			Exercise		Contractual		Value
	Outstanding			Price		Life		(in 000’s)
Outstanding options at January 1, 2020		1,667,290		$	62.52
Options granted		275,977			93.39
Options exercised		(177,045	)		49.13			$	7,639
Options canceled/forfeited		(6,410	)		73.42
Outstanding options at September 30, 2020		1,759,812		$	68.67		5.14	$	29,740
Exercisable options at September 30, 2020		807,570		$	59.03		3.82	$	20,054
						Weighted
				Weighted		Average		Aggregate
	Number of			Average		Remaining		Intrinsic
	Options			Exercise		Contractual		Value
	Outstanding			Price		Life		(in 000’s)
Outstanding options at January 1, 2019		1,964,880		$	54.24
Options granted		324,525			81.27
Options exercised		(493,615	)		45.61			$	18,157
Options canceled/forfeited		(59,050	)		60.92
Outstanding options at September 30, 2019		1,736,740		$	61.52		5.43	$	54,515
Exercisable options at September 30, 2019		622,290		$	52.78		4.03	$	24,975

Summary of Weighted Average Grant-date Assumptions and Weighted Average Fair Values

The fair value of options was estimated using a Black-Scholes based option pricing model with the following weighted average grant-date assumptions and weighted average fair values as of September 30:

	2020			2019
Weighted-average fair value of grants	$	13.33		$	13.47
Risk-free interest rates		0.41	%		2.41	%
Dividend yield		2.30	%		2.69	%
Expected volatility		22.67	%		22.71	%
Expected option life		4.96	years		4.95	years