Number Of Share-Based Compensation Plans

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- Definition

Share-based Compensation Arrangement By Share-based Payment Award, Fair Value Assumptions, Percent Expected To Vest

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- Definition

Amount of cash inflow from exercise of option under share-based payment arrangement.

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- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Number of options outstanding, including both vested and non-vested options.

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- Definition

Number of shares issued under share-based payment arrangement.

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- Definition

Price of a single share of a number of saleable stocks of a company.

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- Definition

Percentage of vesting of award under share-based payment arrangement.

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- Definition

Number of share options (or share units) exercised during the current period.

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Share-Based Compensation (Details) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021 numberOfPlans $ / shares shares	Jun. 30, 2020	Jun. 30, 2021 USD ($) numberOfPlans $ / shares shares	Jun. 30, 2020 $ / shares shares	Dec. 31, 2020 $ / shares	Dec. 31, 2019 $ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Of Share-Based Compensation Plans \| numberOfPlans	2		2
Share-based Compensation Arrangement By Share-based Payment Award, Fair Value Assumptions, Percent Expected To Vest	62.10%	65.50%	57.60%	75.60%
Granted, shares (in shares)				69,368
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period			285,224	248,155
Share-based Payment Arrangement, Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercises in period				0
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period			1,500
Proceeds from Stock Options Exercised \| $			$ 0.1
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	0		0
Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value \| $ / shares				$ 137.63
Key Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares (in shares)				13,873
Weighted average grant date fair value \| $ / shares				$ 140.39
Time Based [Member] \| Director [Member] \| Restricted Stock [Member] \| 2004 Non-employee Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares (in shares)				10,200
Weighted average grant date fair value \| $ / shares				$ 147.97
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Price \| $ / shares	$ 151.89		$ 151.89		$ 147.19	$ 165.97
Award Date One [Member] \| Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares (in shares)			54,000
Weighted average grant date fair value \| $ / shares			$ 151.89
Award Date One [Member] \| Executive Officer [Member] \| Restricted Stock [Member] \| 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage			20.00%	20.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			5 years	5 years
Award Date One [Member] \| Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares (in shares)			1,509
Weighted average grant date fair value \| $ / shares			$ 147.19
Award Date One [Member] \| Director [Member] \| Restricted Stock [Member] \| 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage			100.00%
Award Date One [Member] \| Director [Member] \| Restricted Stock [Member] \| 2004 Non-employee Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage				100.00%
Award Date One [Member] \| Key Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares (in shares)			28,856
Weighted average grant date fair value \| $ / shares			$ 151.89
Award Date One [Member] \| Key Employees [Member] \| Restricted Stock [Member] \| 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage			33.30%	20.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			3 years	5 years
Award Date Two [Member] \| Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares (in shares)			81,000
Weighted average grant date fair value \| $ / shares			$ 94.32
Award Date Two [Member] \| Executive Officer [Member] \| Restricted Stock [Member] \| 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage			100.00%	20.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				5 years
Award Date Two [Member] \| Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares (in shares)			10,200
Award Date Two [Member] \| Director [Member] \| 2004 Non-employee Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value \| $ / shares			$ 148.44
Award Date Two [Member] \| Director [Member] \| Restricted Stock [Member] \| 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage			100.00%
Award Date Two [Member] \| Key Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares (in shares)			61,550
Weighted average grant date fair value \| $ / shares			$ 143.28
Award Date Two [Member] \| Key Employees [Member] \| Restricted Stock [Member] \| 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage			20.00%	20.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			5 years	5 years
Award Date Two [Member] \| Time Based [Member] \| Executive Officer [Member] \| Restricted Stock [Member] \| 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares (in shares)				46,000
Weighted average grant date fair value \| $ / shares				$ 165.97
Award Date Two [Member] \| Time Based [Member] \| Key Employees [Member] \| Restricted Stock [Member] \| 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares (in shares)				1,500
Weighted average grant date fair value \| $ / shares				$ 143.20
Award Date Three \| Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares (in shares)			15,000
Weighted average grant date fair value \| $ / shares			$ 151.89
Award Date Three \| Executive Officer [Member] \| Restricted Stock [Member] \| 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage			33.30%	100.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			3 years
Award Date Three \| Key Employees [Member] \| Restricted Stock [Member] \| 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage				20.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				5 years
Award Date Three \| Time Based [Member] \| Key Employees [Member] \| Restricted Stock [Member] \| 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares (in shares)				51,790
Weighted average grant date fair value \| $ / shares				$ 162.42
Award Date Three \| Market Condition [Member] \| Executive Officer [Member] \| Restricted Stock [Member] \| 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares (in shares)				69,000
Weighted average grant date fair value \| $ / shares				$ 125.47
Award Date Four \| Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares (in shares)			15,000
Weighted average grant date fair value \| $ / shares			$ 87.49
Award Date Four \| Executive Officer [Member] \| Restricted Stock [Member] \| 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage			100.00%
Award Date Five \| Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares (in shares)			3,400
Weighted average grant date fair value \| $ / shares			$ 147.19
Award Date Five \| Executive Officer [Member] \| Restricted Stock [Member] \| 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage			20.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			5 years
Award Date Six
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares (in shares)			5,100
Award Date Six \| Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value \| $ / shares			$ 96.41
Award Date Six \| Executive Officer [Member] \| Restricted Stock [Member] \| 2015 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting percentage			100.00%