Shareholder return award performance measurement period.

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- Definition

Stock option achieving maximum threshold.

+ References

No definition available.

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- Definition

Stock option achieving minimum threshold.

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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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- 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.

+ References

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- Definition

Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

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

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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- 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

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.

+ References

No definition available.

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- Definition

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

+ References

No definition available.

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- Definition

The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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- Definition

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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- 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

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

+ References

No definition available.

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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

Description of pertinent provisions of equity-based compensation awards that have actual or potential impact upon the company's financial statements.

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Accounting for Stock Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	May 19, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2013	Dec. 31, 2015	May 16, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option grant expiration period					10 years
Performance based restricted stock units outstanding		136,566	282,100	210,481		179,026
Shareholder Return Award Performance Measurement Period		3 years
Unrecognized compensation cost related to nonvested options and restricted options		$ 15,932	$ 18,593
Unrecognized share-based compensation cost recognition period		2 years
Share based compensation expense		$ 12,177	$ 12,727	$ 8,147
Granted, Shares		0	808,500	862,000
Weighted average grant date fair value of options granted			$ 9.11	$ 10.74
Total intrinsic value of options exercised		$ 5,061	$ 4,715	$ 2,456
Total fair value of restricted shares vested		$ 4,599	$ 6,006	$ 3,865
Granted, Shares		21,681	237,542	141,784
Performance Based Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance based restricted stock units outstanding		129,577
These awards vesting period		3 years
Stock option achieving minimum threshold		50.00%
Stock option achieving maximum threshold		200.00%
RSU
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance based restricted stock units outstanding		215,969
Granted, Shares		215,969	0
Stock Appreciation Rights (SARs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted, Shares			235,000	244,000
Total intrinsic value of options exercised		$ 3,532	$ 1,495	$ 261
ROIC \| Performance Based Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance based restricted stock payment condition		one-half
TSR \| Performance Based Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance based restricted stock payment condition		one-half
Employee and Consultants \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation, requisite service period		3 years
Employee and Consultants \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation, requisite service period		5 years
Director
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation, requisite service period		1 year
2013 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized for grant		1,567,594
Number of shares authorized for grant							3,500,000
Number of increased shares available for grant	2,000,000
Equity Incentive Plan Twenty Eleven and Two Thousand and Six
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares authorized for grant							0