The number of shares purchased by employees under the investment share purchase program.

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Share based compensation arrangement by share based payment award, fair value assumptions, estimated forfeiture rate.

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Employee tenure requirement to participate in plan.

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Stock repurchase program, cumulative number of shares repurchased.

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Stock repurchase program, cumulative shares repurchased, value.

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Voluntary payroll deduction period to purchase investment shares.

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No definition available.

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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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Discount rate from fair value on purchase date that participants pay for shares.

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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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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 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

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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- Definition

Number of shares authorized for issuance under share-based payment arrangement.

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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

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

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No definition available.

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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

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

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

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Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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Number of options vested.

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No definition available.

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Weighted average grant-date fair value of options vested.

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Common Stock and Share-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Apr. 30, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, contractual term		5 years 9 months
Other than options granted in period		30,410
Options granted in period - weighted average fair value		$ 131.91	$ 92.89	$ 72.52
Stock option outstanding		315,678	366,829
Estimated forfeiture rate for equity awards that do not vest on January 1st		11.00%
Weighted average fair value of stock awards		$ 269.91
Expected dividends		0.00%	0.00%	0.00%
Total fair value of options vested in period		$ 2,500	$ 3,200	$ 2,900
Aggregate intrinsic value of stock options exercised in period		20,900	$ 19,200	$ 14,900
Unrecognized compensation costs		$ 24,825
Unrecognized compensation costs, weighted average period		2 years
Option vested, number of shares		33,205	20,678	22,213
Option vested, weighted average fair value		$ 188.63	$ 156.50	$ 151.32
Repurchase of shares		13,797,037	13,797,037	13,447,346	12,483,556
Repurchased of value		$ 840,664	$ 840,664	$ 752,352	$ 607,750
President and Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted in period	9,959
Options granted in period - weighted average fair value	$ 100.50
Performance-Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option outstanding		65,306
Performance-Based Awards \| Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option outstanding		40,607
Non-Employee Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted in period		4,779	5,080	10,188
Non-Employee Director \| Common Class A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for issuance		600,000
Shares available for grant		100,000
Non-Employee Director \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, contractual term		10 years
Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options granted in period		22,509	83,561	15,800
Restricted Stock Awards \| Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other than options granted in period	64,325
Weighted average fair value of stock awards	$ 229.30
Restricted Stock Awards \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		5 years
Restricted Stock Awards \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		1 year
Employee Stock Compensation Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted in period		26,507	27,490	5,185
Employee Stock Compensation Plan \| Common Class A
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for issuance		6,700,000
Shares available for grant		1,100,000
Employee Stock Compensation Plan \| Performance-Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted in period		14,680
Employee Stock Compensation Plan \| Service-Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted in period		11,827
Employee Stock Compensation Plan \| Investment Share Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		5 years
Payroll deduction period		11 months
Shares employees elected to purchase		7,901	9,214	10,146
Employee Stock Compensation Plan \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		5 years
Stock options, contractual term		10 years
Employee Stock Compensation Plan \| Maximum \| Investment Share Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Discount from current market value		40.00%
Employee Stock Compensation Plan \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Employee Stock Compensation Plan \| Minimum \| Investment Share Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Requirement tenure of employee for investment share program		1 year
Discount from current market value		0.00%