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Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Approximate number of shares employees purchased under the Employee Stock Purchase Plan | 891,065 |  |
2014 Stock Incentive Plan [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Total aggregate number of shares of common stock that may be issued | 12,840,000 |  |
Performance-Based Restricted Stock and Performance-Based Restricted Stock Units [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Compensation cost recognition period for unvested awards | 1 year 8 months 12 days |  |
Unrecognized compensation cost related to unvested awards | $ 0.8 | $ 1.6 | $ 1.8
Vesting period | 3 years |  |
Stock Appreciation Rights [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Unrecognized compensation cost related to unvested awards | $ 0.4 |  |
Fair value assumptions method used | Black-Scholes option-pricing |  |
Weighted-average fair value of grants | $ 29.56 | $ 22.09 | $ 13.99
Time-Based Restricted Stock and Time-Based Restricted Stock Units [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Unrecognized compensation cost related to unvested awards | $ 3.2 |  |
Total fair value of restricted shares vested | $ 6.0 | $ 5.1 | $ 5.5
Employee Stock Purchase Plan [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Total aggregate number of shares of common stock that may be issued | 1,200,000 |  |
Percentage of market price on lesser of either first day of calendar quarter or last day of calendar quarter for purchase price | 85.00% |  |
Percentage of gross compensation eligible employees may elect to participate in the plan | 15.00% |  |
Maximum [Member] | Performance-Based Restricted Stock and Performance-Based Restricted Stock Units [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Percentage of target number of shares that will vest | 200.00% |  |
Minimum [Member] | Performance-Based Restricted Stock and Performance-Based Restricted Stock Units [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Percentage of target number of shares that will vest | 0.00% |  |

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- Definition 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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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- Definition 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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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- Definition The highest percentage of annual salary that an employee is permitted to utilize with respect to the plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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