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

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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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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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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

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Stock-Based Compensation - Summary of Activity in Corporation's Active Stock Plans (Detail) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options exercised, Number of Shares	(101,284)	(19,232)	(255,184)	(447,831)
Director deferred stock units outstanding [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance, Number of Shares/Units			48,910
Granted, Number of Units			7,592
Stock Awards exercised/vested, Number of Shares			(1,132)
Ending Balance, Number of Shares/Units	55,370		55,370
Beginning Balance, Weighted-Average Grant-Date Fair Value			$ 71.14
Granted Weighted-Average Grant-Date Fair Value			102.70
Stock Award Exercised/Vested, Weighted Average Grant Date Fair Value			106.03
Ending Balance, Weighted-Average Grant-Date Fair Value	$ 74.76		$ 74.76
Non-Vested Stock Awards/Stock Units Outstanding [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance, Number of Shares/Units			383,797
Granted, Number of Units			1,957
Stock Awards exercised/vested, Number of Shares			(17,800)
Forfeited/expired, Number of Shares/Units			(11,850)
Ending Balance, Number of Shares/Units	356,104		356,104
Beginning Balance, Weighted-Average Grant-Date Fair Value			$ 85.59
Granted Weighted-Average Grant-Date Fair Value			91.96
Stock Award Exercised/Vested, Weighted Average Grant Date Fair Value			65.11
Forfeited/Expired, Weighted-Average Price			89.29
Ending Balance, Weighted-Average Grant-Date Fair Value	$ 86.53		$ 86.53
Stock Options Outstanding [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance, Number of Shares			2,352,008
Stock options exercised, Number of Shares			(236,252)
Forfeited/expired, Number of Shares			(11,000)
Ending Balance, Number of Shares	2,104,756		2,104,756
Beginning Balance, Weighted-Average Exercise Price			$ 63.55
Stock options exercised, Weighted-Average Exercise Price			57.17
Forfeited/expired, Weighted-Average Exercise Price			65.11
Ending Balance, Weighted-Average Exercise Price	$ 64.26		$ 64.26
Maximum [Member] \| Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning Balance, Number of Shares/Units			125,809
Ending Balance, Number of Shares/Units	125,809		125,809
Beginning Balance, Weighted-Average Grant-Date Fair Value			$ 82.55
Ending Balance, Weighted-Average Grant-Date Fair Value	$ 82.55		$ 82.55