Closing price of common stock.

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Number of awards excluded from option-pricing model.

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Percentage of shares grant to participants.

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Share-based compensation arrangement by share-based payment award award vesting date.

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Share based compensation arrangement by share based payment award equity instruments other than options performance shares payout range maximum.

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Share based compensation arrangement by share based payment award equity instruments other than options performance shares payout range minimum.

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Share-based compensation arrangement by share-based payment award equity instruments other than options purchase price of common stock percent.

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Share-based compensation arrangement by share-based payment award period.

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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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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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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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

Date the equity-based award expires, in CCYY-MM-DD format.

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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The risk-free interest rate assumption that is used in valuing an option on its own shares.

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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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No definition available.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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- Definition

Net number of share options (or share units) granted during the period.

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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- Definition

Purchase price of common stock expressed as a percentage of its fair value.

+ References

No definition available.

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Stock-Based Compensation Plans - Additional Information (Detail) - USD ($)	1 Months Ended			12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Nov. 30, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for grant under the stock incentive plans				2,531,199
Weighted-average fair value option granted				$ 91.43	$ 58.37	$ 56.11
Number of awards excluded from option-pricing model				2
Grant date fair value				$ 76,709,000
Fair value assumptions, Dividend yield rate				0.60%	0.80%	0.80%
Closing price of common stock				$ 570.56
Unrecognized compensation costs related to non-vested				$ 5,900,000
Weighted-average period over which cost is expected to be recognized				2 years 4 months 24 days
Pay-out ranges, Minimum				0.00%
Pay-out ranges, Maximum				150.00%
Grant date deemed probable to vest				$ 43,025,000
Incentive Stock Options [Member] \| President and Chief Operating Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of stock option equity instruments granted during the period		76,868
Grant date fair value		$ 2,900,000
Share-based compensation arrangement by share-based payment award award vesting date		Jan. 22, 2024
Fair value assumptions, Risk free interest rate		2.60%
Fair value assumptions, Volatility rate		25.80%
Fair value assumptions, Dividend yield rate		0.80%
Share-based compensation arrangement by share-based payment award, options expiry date		Jul. 22, 2024
Incentive Stock Options [Member] \| President and Chief Operating Officer [Member] \| Range One [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average fair value option granted		$ 272.88
Number of stock option equity instruments granted during the period		35,679
Percentage of fair market value of the common stock on the grant date		125.00%
Incentive Stock Options [Member] \| President and Chief Operating Officer [Member] \| Range Two [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average fair value option granted		$ 294.71
Number of stock option equity instruments granted during the period		41,189
Percentage of fair market value of the common stock on the grant date		135.00%
Incentive Stock Options [Member] \| Chief Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of stock option equity instruments granted during the period			148,524
Grant date fair value			$ 5,500,000
Share-based compensation arrangement by share-based payment award award vesting date			Nov. 08, 2023
Fair value assumptions, Risk free interest rate			3.10%
Fair value assumptions, Volatility rate			25.90%
Fair value assumptions, Dividend yield rate			0.80%
Share-based compensation arrangement by share-based payment award, options expiry date			May 08, 2024
Incentive Stock Options [Member] \| Chief Executive Officer [Member] \| Range One [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average fair value option granted			$ 257.78
Number of stock option equity instruments granted during the period			69,113
Percentage of fair market value of the common stock on the grant date			125.00%
Incentive Stock Options [Member] \| Chief Executive Officer [Member] \| Range Two [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average fair value option granted			$ 278.40
Number of stock option equity instruments granted during the period			79,411
Percentage of fair market value of the common stock on the grant date			135.00%
Restricted Stock and Performance Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation costs related to non-vested				$ 27,000,000.0
Weighted-average period over which cost is expected to be recognized				1 year 6 months
Performance Based Share [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Grant date fair value	$ 368,100
Pay-out ranges, Minimum	0.00%
Pay-out ranges, Maximum	15000.00%
Performance period	3 years
Number of non-option equity instruments granted during the period	13,295
Grant date deemed probable to vest		$ 15,319,000
Performance Based Share [Member] \| Chief Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Grant date fair value			$ 5,500,000
Share-based compensation arrangement by share-based payment award award vesting date			Nov. 08, 2023
Fair value assumptions, Risk free interest rate			3.10%
Fair value assumptions, Volatility rate			26.10%
Fair value assumptions, Dividend yield rate			0.80%
Performance period			5 years
Number of non-option equity instruments granted during the period			37,742
Performance Based Share [Member] \| Chief Executive Officer [Member] \| Range One [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of non-option equity instruments granted during the period			17,942
Fair value per share on the grant date			$ 257.78
Percentage of fair market value of the common stock on the grant date			125.00%
Performance Based Share [Member] \| Chief Executive Officer [Member] \| Range Two [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of non-option equity instruments granted during the period			19,800
Fair value per share on the grant date			$ 278.40
Percentage of fair market value of the common stock on the grant date			135.00%
Performance Based Share [Member] \| Chief Operating Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Grant date fair value		$ 2,900,000
Share-based compensation arrangement by share-based payment award award vesting date		Jan. 22, 2024
Fair value assumptions, Risk free interest rate		2.60%
Fair value assumptions, Volatility rate		25.90%
Fair value assumptions, Dividend yield rate		0.80%
Performance period		5 years
Number of non-option equity instruments granted during the period		18,914
Performance Based Share [Member] \| Chief Operating Officer [Member] \| Range One [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of non-option equity instruments granted during the period		8,969
Fair value per share on the grant date		$ 272.88
Percentage of fair market value of the common stock on the grant date		125.00%
Performance Based Share [Member] \| Chief Operating Officer [Member] \| Range Two [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of non-option equity instruments granted during the period		9,945
Fair value per share on the grant date		$ 294.71
Percentage of fair market value of the common stock on the grant date		135.00%
Employees Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Period vested for option grants				1 year
Number of non-option equity instruments granted during the period				729	617	989
Percentage of shares grant to participants				20.00%
Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Period vested for option grants				3 years
Options Expiration Period				6 years
Minimum [Member] \| Restricted Stock and Performance Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Period vested for option grants				3 years
Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Period vested for option grants				5 years
Options Expiration Period				10 years
Maximum [Member] \| Restricted Stock and Performance Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Period vested for option grants				5 years