Defined Contribution Plan Employer Discretionary Maximum Contribution Amount Per Participant

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- Definition

Discount percentage on purchase of stock.

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value of stock purchase right percentage of put option.

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- Definition

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Aggregate number of common shares reserved for future issuance.

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Amount of the cumulative effect on retained earnings net of related income tax effect.

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- Definition

This represents the current liability recognized in the balance sheet that is associated with the defined benefit pension plans.

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This represents the noncurrent liability recognized in the balance sheet that is associated with the defined benefit pension plans.

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1) For defined benefit pension plans, the benefit obligation is the projected benefit obligation, which is the actuarial present value as of a date of all benefits attributed by the pension benefit formula to employee service rendered prior to that date. 2) For other postretirement defined benefit plans, the benefit obligation is the accumulated postretirement benefit obligation, which is the actuarial present value of benefits attributed to employee service rendered to a particular date.

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- Definition

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

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No definition available.

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- Definition

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

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No definition available.

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

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No definition available.

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- Definition

Unrecognized cost of unvested share-based compensation awards.

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Disclosure of the aggregate tax benefit realized from the exercise of stock options and the conversion of similar instruments during the annual period.

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- Definition

The amount of cash or cash equivalents contributed during the reporting period by the entity to fund its pension plans and its non-pension postretirement benefit plans.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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

Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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

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Weighted average expected volatility rate of share-based compensation awards.

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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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- Definition

Number of additional shares authorized for issuance under an established share-based compensation plan.

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No definition available.

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- Definition

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

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

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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- 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 ($)		1 Months Ended		2 Months Ended	3 Months Ended		6 Months Ended
	Jan. 01, 2017	Mar. 31, 2017	Aug. 31, 2016	Apr. 30, 2017	Jun. 30, 2017	Jul. 01, 2016	Jun. 30, 2017	Jul. 01, 2016	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increased Number of Common Shares Reserved for Issuance							7,400,000
Intrinsic value of options exercised					$ 24,000		$ 200,000
Defined Benefit Plan, Benefit Obligation					4,779,000		4,779,000		$ 4,300,000
Defined Benefit Pension Plan Liabilities, Current					45,000		45,000
Defined Benefit Pension Plan, Liabilities, Noncurrent					4,734,000		$ 4,734,000
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							285,000	$ 241,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized					16,500,000		$ 16,500,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition							1 year 7 months 17 days
Total stock-based compensation					$ 4,136,000	$ 2,768,000	$ 7,387,000	$ 5,862,000
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility					43.00%	36.00%	43.00%	36.00%
Risk-free interest rate					1.70%	1.10%	1.70%	1.40%
Expected dividends					0.00%	0.00%	0.00%	0.00%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value					$ 1.85	$ 1.07	$ 1.85	$ 0.97
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value					$ 400,000	$ 400,000	$ 1,100,000	$ 1,400,000
Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options					0	0	$ 0	0
Performance-based Restricted Stock Units [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			898,533	582,806
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							344,500
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period							3 years
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized					900,000		$ 900,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition							8 months 16 days
Volatility		46.70%
Risk-free interest rate		1.57%
Expected dividends		0.00%
Total stock-based compensation					368,000		$ 415,000
RSUs and PRSUs [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, Vested in Period, Fair Value					$ 800,000	$ 500,000	$ 7,400,000	$ 7,100,000
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance					1,693,295		1,693,295
Discount Percentage On Purchase Of Stock							15.00%
Percentage of fair market value of Common Stock to purchase shares							85.00%
Value Of Stock Purchase Right Percentage Of Put Option							15.00%
Minimum [Member] \| Performance-based Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				3 months
Maximum [Member] \| Performance-based Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				6 months
TVN [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pension and Other Postretirement Benefit Contributions					$ 0
Stock Plan 1995 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increased Number of Common Shares Reserved for Issuance					7,000,000
Stock Plan 1995 [Member] \| Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increased Number of Common Shares Reserved for Issuance					1,500,000
Director Option Plans 2002 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increased Number of Common Shares Reserved for Issuance					400,000
Accounting Standards Update 2016-09 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Granted, Value, Share-based Compensation, Forfeited	$ 69,000