Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands |
1 Months Ended | 3 Months Ended | 6 Months Ended | 11 Months Ended | |||
|---|---|---|---|---|---|---|---|
Mar. 04, 2019 |
Jan. 31, 2018 |
Jul. 31, 2019 |
Jul. 31, 2018 |
Jul. 31, 2019 |
Jul. 31, 2018 |
Dec. 31, 2017 |
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| Income Tax Disclosure [Abstract] | |||||||
| Income tax benefit | $ 563 | $ 1,152 | $ 161 | $ 1,646 | |||
| Corporate federal income tax rate | 21.00% | 35.00% | |||||
| Preferred shares purchase rights, declared date as dividend | Mar. 04, 2019 | ||||||
| Preferred shares purchase rights for each common stock | 1 | ||||||
| Preferred shares purchase rights, record date as dividend | Mar. 15, 2019 | ||||||
| Tax benefits preservation plan expiration date | Mar. 04, 2022 | ||||||
| X | ||||||||||
- Definition Number of preferred share purchase rights as dividend. No definition available.
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| X | ||||||||||
- Definition Preferred share purchase rights as dividend payable date declared day month and year. No definition available.
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| X | ||||||||||
- Definition Preferred share purchase rights as dividend payable date of record day month and year. No definition available.
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| X | ||||||||||
- 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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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Expiration date of each operating loss carryforward included in operating loss carryforward, in CCYY-MM-DD format. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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