Share-based Compensation Arrangement by Share-based Payment Award, Awards, Grants in Period, Fair Value

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Aggregate number of common shares reserved for future issuance.

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Amount of liability, recognized in statement of financial position, for defined benefit pension plan, classified as current. Excludes other postretirement benefit plan.

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Amount of liability, recognized in statement of financial position, for defined benefit pension plan, classified as noncurrent. Excludes other postretirement benefit plan.

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Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

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Amount of discretionary contributions made by an employer to a defined contribution plan.

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Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

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Percentage employer matches of the employee's percentage contribution matched.

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Maximum amount the employee may contribute to a defined contribution plan.

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Amount of paid and unpaid cash dividends declared for award under share-based payment arrangement.

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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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- Definition

Amount of cost to be recognized for option under share-based payment arrangement.

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Amount of tax benefit from exercise of option under share-based payment arrangement.

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Amount of cash outflow for pension and other postretirement benefits. Includes, but is not limited to, employer contribution to fund plan asset and payment to retiree.

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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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- Definition

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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- Definition

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

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

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- Definition

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

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- Definition

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

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Employee Benefit Plans and Stock-based Compensation - Additional Information (Detail) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 27, 2019	Jun. 28, 2019	Sep. 28, 2018	Sep. 27, 2019	Sep. 28, 2018	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Exercise of Option, Tax Benefit				$ 0	$ 0
Defined Benefit Plan, Benefit Obligation	$ 4,900,000			4,900,000		$ 4,900,000
Liability, Defined Benefit Pension Plan, Current	100,000			100,000
Liability, Defined Benefit Pension Plan, Noncurrent	4,800,000			$ 4,800,000
Discretionary contributions of plan				25.00%
Percent of employees' gross pay eligible for matching				4.00%
Maximum contribution amount per participant				$ 1,000
Contributions in period				245,000	259,000
Dividend, Share-based Payment Arrangement, Cash				0
Total stock-based compensation	$ 4,096,000		$ 5,433,000	$ 8,719,000	$ 14,202,000
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized				1,000,000
Common Stock, Capital Shares Reserved for Future Issuance	1,200,000			1,200,000
Discount Percentage On Purchase Of Stock				15.00%
Share-based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized				3,500,000
Common Stock, Capital Shares Reserved for Future Issuance	5,100,000			5,100,000
Grants in Period, Number of Shares				0
Market-based awards [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, Grants in Period		200,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		3 years
Share-based Compensation Arrangement by Share-based Payment Award, Awards, Grants in Period, Fair Value		$ 1,100,000
Total stock-based compensation	$ 100,000			$ 200,000
Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount	900,000			$ 900,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period				0
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount	$ 15,700,000			$ 15,700,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition				1 year 5 months 27 days
TVN [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payment for Pension and Other Postretirement Benefits				$ 0
Call Option [Member] \| Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of fair market value of Common Stock to purchase shares				85.00%
Put Option [Member] \| Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of fair market value of Common Stock to purchase shares				15.00%