| Fair Value Measurements - Additional Information (Detail) | Jun. 30, 2019  USD ($) | 
|---|---|
| Fair Value Disclosures [Abstract] | |
| Carrying value of notes | $ 231,900,000 | 
| Debt instrument, estimated fair value | $ 203,500,000 | 
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- Definition Face (par) amount of debt instrument at time of issuance. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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| X | ||||||||||
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- Definition Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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| X | ||||||||||
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- References No definition available. 
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