The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under 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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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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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 floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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Weighted average remaining contractual term of outstanding stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Stock-Based Compensation and Stock Options - Stock Options Outstanding and Exercisable (Detail) - $ / shares	3 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Outstanding Options	1,017,494	1,029,103	1,000,830	1,058,411
Weighted Average Remaining Contractual Life	3 years 2 months 23 days
Outstanding Options – Weighted Average Exercise Price	$ 55.54	$ 54.87	$ 47.05	$ 45.17
Exercisable Options – Number of Exercisable Options	459,763
Exercisable Options – Weighted Average Exercise Price	$ 43.07
Range of Exercise Price, $20.08 to $45.90 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, lower limit	20.08
Range of Exercise Price, upper limit	$ 45.90
Number of Outstanding Options	299,748
Weighted Average Remaining Contractual Life	2 years 7 days
Outstanding Options – Weighted Average Exercise Price	$ 34.99
Exercisable Options – Number of Exercisable Options	274,388
Exercisable Options – Weighted Average Exercise Price	$ 34.27
Range of Exercise Price, $45.91 to $57.75 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, lower limit	45.91
Range of Exercise Price, upper limit	$ 57.75
Number of Outstanding Options	327,027
Weighted Average Remaining Contractual Life	3 years 3 months 14 days
Outstanding Options – Weighted Average Exercise Price	$ 53.95
Exercisable Options – Number of Exercisable Options	138,692
Exercisable Options – Weighted Average Exercise Price	$ 53.86
Range of Exercise Price, $57.76 to $77.93 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, lower limit	57.76
Range of Exercise Price, upper limit	$ 77.93
Number of Outstanding Options	314,669
Weighted Average Remaining Contractual Life	3 years 10 months 2 days
Outstanding Options – Weighted Average Exercise Price	$ 68.97
Exercisable Options – Number of Exercisable Options	46,683
Exercisable Options – Weighted Average Exercise Price	$ 62.68
Range of Exercise Price, $77.94 to $88.22 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Price, lower limit	77.94
Range of Exercise Price, upper limit	$ 88.22
Number of Outstanding Options	76,050
Weighted Average Remaining Contractual Life	5 years 3 months 10 days
Outstanding Options – Weighted Average Exercise Price	$ 87.76
Exercisable Options – Number of Exercisable Options	0
Exercisable Options – Weighted Average Exercise Price	$ 0