Share Based Award (Tables)

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

Schedule of stock compensation and related tax benefits [Table Text Block]

The table below summarizes compensation costs and related tax benefits (in thousands):

	Year ended December 31,
(In thousands)	2020		2019		2018
Stock compensation expense	$	23,954	$	21,918	$	24,241
Tax benefit from stock-based compensation cost	$	5,564	$	4,840	$	5,706
Indirect tax benefit	$	1,203	$	680	$	2,199

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

The table below summarizes the total time-based stock options granted, total valuation and the weighted average assumptions (dollars in thousands, except per option amounts):

	Year ended December 31,
	2020			2019			2018
Number of time-based options granted	7,190			6,265			5,815
Grant date fair value of options granted (in thousands)	$	425		$	424		$	425
Weighted average assumptions for stock option valuation:
Expected term (years)	5.5			5.5			5.5
Expected stock price volatility	35.0		%	28.0		%	24.0		%
Risk-free interest rate	0.4		%	2.2		%	2.3		%
Expected dividend yield	—		%	—		%	—		%
Weighted average grant price per option	$	181.99		$	225.27		$	269.80
Weighted average grant date fair value per option	$	59.09		$	67.73		$	73.14

Share-based Payment Arrangement, Option, Activity [Table Text Block]

A summary of our stock option activity as of and for the year ended December 31, 2020 is as follows:

	Shares	Weighted Average Exercise Price Per Share		Weighted Average Contractual Life (Years)	Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2019	1,047,854	$	66.08
Granted	7,190	$	181.99
Exercised	(237,244)	$	55.60
Forfeited or expired	—	$	—
Outstanding at December 31, 2020	817,800	$	70.13	3.3	$	118,444
Exercisable at December 31, 2020	810,616	$	69.14	3.3	$	118,210
Vested and expected to vest, December 31, 2020	817,800	$	70.13	3.3	$	118,444

Exercised Options Data [Table Text Block]

The following table presents information regarding stock option activity:

	Year ended December 31,
(In thousands)	2020		2019		2018
Intrinsic value of options exercised	$	32,915	$	22,976	$	51,105
Cash received from exercise of stock options	$	13,193	$	7,732	$	14,275
Tax benefit from stock option exercises	$	5,179	$	9,653	$	12,617

Share-based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block]

The table below summarizes our restricted stock award activity (dollars in thousands):

	Year ended December 31,
(In thousands except shares and per share amounts)	2020		2019		2018
PRSU
Shares granted	38,633		37,657		30,348
Shares earned (a)	80,654		114,032		—
Grant date fair value per share	$	188.34	$	231.63	$	248.65
Grant date fair value	$	7,276	$	8,723	$	7,546
Intrinsic value vested	$	15,627	$	26,445	$	—
RSU
Shares granted	87,830		61,856		63,094
Grant date fair value per share	$	188.13	$	227.42	$	252.42
Grant date fair value	$	16,523	$	14,067	$	15,926
Intrinsic value vested	$	12,314	$	16,753	$	17,086

Nonvested Restricted Stock Shares Activity [Table Text Block]

The table below provides a summary of our PRSU and RSU activity as of and for the year ended December 31, 2020:  

	Number of Units	Grant Date Fair Value Per Share		Weighted Average Contractual Life (Years)	Aggregate Intrinsic Value
Non-vested at December 31, 2019	232,527	$	205.82
Change in units due to performance expectations (a)	15,454	$	238.66
Granted	126,463	$	188.19
Vested	(145,820)	$	187.97
Forfeited	(7,864)	$	207.02
Non-vested and expected to vest at December 31, 2020	220,760	$	209.77	1.0	$	47,351