Stock Plans - Summary of Fair Value Per Share Determined for Each of Three Equal Tranches of Award (Detail) - 2018 Performance- Based Stock Incentive Plan [Member] |
Dec. 31, 2018
$ / shares
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| Tranche 1 [Member] | |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |
| Fair value per share | $ 9.22 |
| Tranche 2 [Member] | |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |
| Fair value per share | 10.05 |
| Tranche 3 [Member] | |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |
| Fair value per share | $ 9.50 |
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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. No definition available.
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- Definition Price of a single share of a number of saleable stocks of a company. No definition available.
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