Share-Based Compensation - Additional Information (Detail) - USD ($) |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2019 |
Jun. 30, 2018 |
Jun. 30, 2019 |
Jun. 30, 2018 |
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| Share-based compensation expense | $ 9,900,000 | $ 10,400,000 | $ 20,500,000 | $ 20,200,000 |
| Unrecognized compensation cost on non-vested stock awards | 71,500,000 | $ 71,500,000 | ||
| Unrecognized compensation cost on non-vested stock awards, weighted-average period of recognition | 1 year 7 months 6 days | |||
| Total vesting date fair value of stock units | $ 1,900,000 | $ 2,100,000 | $ 10,900,000 | $ 2,100,000 |
| SARs [Member] | ||||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||||
| SARs granted | 0 | 0 | 0 | 0 |
| Total intrinsic value of awards exercised for SARs | $ 5,300,000 | $ 64,800,000 | $ 17,200,000 | $ 187,000,000.0 |
| X | ||||||||||
- Definition Intrinsic value of awards exercised for stock appreciation rights. No definition available.
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| X | ||||||||||
- 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. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Unrecognized cost of unvested share-based compensation awards. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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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. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- 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. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- 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. No definition available.
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- Definition Net number of non-option equity instruments granted to participants. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Details
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