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Shared-Based Compensation - Additional Information (Detail) $ / shares in Units, $ in Millions |  | 9 Months Ended
--- | --- | ---
Aug. 17, 2017 USD ($) Member shares | Sep. 30, 2017 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Options awards vested | shares | 58,094 |
Vesting period of stock issue | 2 years |
Number of options granted | shares |  | 126,000
Weighted average grant date fair value of the options granted | $ / shares |  | $ 11.84
Weighted-Average Exercise Price, Granted | $ / shares |  | $ 24.20
Model used to derive fair value |  | Monte Carlo valuation model
Discontinued Operations, Disposed of by Sale [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Incremental compensation costs | $ | $ 0.8 |
Performance Condition [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Weighted-Average Exercise Price, Granted | $ / shares |  | $ 24.20
Monte Carlo Valuation Model [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Weighted-Average Exercise Price, Granted | $ / shares |  | $ 29.84
Performance Based Stock Units [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Compensation expense period |  | 3 years
Restricted Stock [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Restricted stock awards accelerated | shares | 25,564 |
Stock units granted | shares |  | 85,393
Fair value assumptions, exercise price | $ / shares |  | $ 24.29
Non-executive Directors [Member] | Restricted Stock [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Vesting period of stock issue |  | 1 year
Officers and Key Employees [Member] | Performance Based Stock Units [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Stock units granted | shares |  | 98,618
Officers and Key Employees [Member] | Restricted Stock [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Vesting period of stock issue |  | 3 years
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 |

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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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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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). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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- Definition Agreed-upon price for the exchange of the underlying asset relating to the share-based payment award. + References No definition available. + Details
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- Definition For each plan, identification of the award pricing model or other valuation method used in calculating the weighted average fair values disclosed. The model is also used to calculate the compensation expense that is shown within the balance sheet, income statement, and cash flow. Examples of valuation techniques are lattice models (binomial model), closed-form models (Black-Scholes-Merton formula), and a Monte Carlo simulation technique. Fair value is the amount at which an asset or liability could be bought or incurred or sold or settled in a current transaction between willing parties, that is, other than in a forced or liquidation sale. May include disclosures about the assumptions underlying application of the method selected. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(1) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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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. + Details
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- Definition Net number of share options (or share units) granted during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iv)(1) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d)(1) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(2)(iii) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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- Definition Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options. + References No definition available. + Details
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- Definition Number of options vested. + References No definition available. + Details
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