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Share based compensation arrangement by share based payment award maximum number of shares available.

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Share based compensation arrangement by share based payment award percentage of shares issuable based on threshold performance.

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Share based compensation arrangement by share based payment award terms of award.

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Share based compensation arrangement by share-based payment award percentage of shares issuable based on maximum performance.

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Share based compensation arrangement by share-based payment award, percentage of shares Issuable based on target performance.

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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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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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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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Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

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- Definition

The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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The aggregate cash inflow comprised of the amount received from (a) employees to acquire the entity's shares under incentive awards, including stock option exercises and restricted stock arrangements, and (b) the excess tax benefit arising from such transactions.

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Amount of cash inflow from exercise of stock options granted under share-based compensation arrangement.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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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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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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Agreed-upon price for the exchange of the underlying asset relating to the share-based payment award.

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

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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

An excess of the fair value of the modified award over the fair value of the award immediately before the modification.

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Number of shares for which recognition of compensation cost was accelerated.

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Number of options vested.

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Share-Based Compensation - Additional Information (Detail)		3 Months Ended	12 Months Ended
	Aug. 17, 2017 USD ($) Member shares	Dec. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares authorized to issued as options \| shares		1,900,000	1,900,000
Share-based compensation expense \| $			$ 5,496,000	$ 3,935,000	$ 4,039,000
Tax benefit for share-based compensation cost \| $			1,600,000	$ 600,000	$ 600,000
Unrecognized compensation costs related to unvested awards \| $		$ 4,600,000	$ 4,600,000
Unrecognized compensation costs, period for recognition			2 years
Term life of options			10 years
Stock awards granted vesting period	2 years		3 years
Number of options granted \| shares			126,000	167,000	54,100
Weighted average grant date fair value of the options granted \| $ / shares			$ 11.84	$ 5.02	$ 12.61
Cash proceeds from the exercise of options \| $			$ 3,110,000	$ 2,832,000	$ 2,041,000
Total intrinsic value of options exercised \| $			3,784,000	2,900,000	2,600,000
Tax benefit recognized from stock option exercises \| $			200,000		100,000
Options awards vested \| shares	58,094
Selling, General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense \| $			$ 1,000,000	$ 500,000	$ 700,000
Discontinued Operations, Disposed of by Sale [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incremental compensation costs \| $	$ 800,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards granted vesting period			3 years
Stock units issued \| shares			85,000	152,510	114,475
Fair value assumptions, exercise price \| $ / shares		$ 24.29	$ 24.29
Options awards vested \| shares			2,100,000	2,600,000	1,200,000
Restricted stock awards accelerated \| shares	25,564
TSR Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock units issued \| shares			46,000
Options awards vested \| shares			1,200,000
Percentage of shares issuable based on threshold performance			50.00%	50.00%	50.00%
Percentage of shares issuable based on target performance			100.00%	100.00%	100.00%
Percentage of shares issuable based on maximum performance			150.00%	150.00%	150.00%
ROIC Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock units issued \| shares			53,000
Options awards vested \| shares			900,000
Percentage of shares issuable based on threshold performance			35.00%	35.00%	35.00%
Percentage of shares issuable based on target performance			100.00%	100.00%	100.00%
Percentage of shares issuable based on maximum performance			150.00%	150.00%	150.00%
ROIC Awards [Member] \| Selling, General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense \| $		$ 400,000
Officers and Key Employees [Member] \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards granted vesting period			3 years
Non-executive Directors [Member] \| Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards granted vesting period			1 year
Executive Management [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of members who got vesting of share-based awards \| Member	19
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Tax benefit recognized from stock option exercises \| $				$ 100,000