Income Taxes - Additional Information (Detail) - USD ($)  | 
5 Months Ended | 12 Months Ended | |||
|---|---|---|---|---|---|
May 31, 2018  | 
May 31, 2018  | 
Dec. 31, 2017  | 
May 31, 2017  | 
May 31, 2016  | 
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| Schedule Of Income Taxes [Line Items] | |||||
| Net deferred tax benefit (expense) | $ 0 | $ 0 | $ 0 | ||
| Effective income tax rate reconciliation, at blended income tax rate, percent | 28.62% | 28.60% | |||
| Federal statutory income tax rate | 21.00% | 28.60% | 35.00% | 34.00% | 34.00% | 
| Net operating loss | $ 139,200,000 | $ 139,200,000 | $ 95,600,000 | $ 69,100,000 | |
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- Definition Schedule Of Income Taxes [Line Items] No definition available. 
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- Definition Tax cuts and jobs act of 2017, blended tax rate. No definition available. 
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- Definition Amount of deferred income tax expense (benefit) pertaining to income (loss) from continuing operations. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards that are subject to expiration dates. No definition available. 
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- Definition Percentage of domestic federal statutory tax rate applicable to pretax income (loss). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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