| Financial Instruments - Additional Information (Details Textuals) | 3 Months Ended | 9 Months Ended | 
|---|---|---|
| Sep. 30, 2018  USD ($) | Sep. 30, 2018  USD ($) | |
| Fair Value Disclosures [Abstract] | ||
| Fair Value, Assets, Level 2 to Level 1 Transfers, Amount | $ 0 | $ 0 | 
| Fair Value, Assets, Level 1 to Level 2 Transfers, Amount | 0 | 0 | 
| Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net | $ 0 | $ 0 | 
| X | ||||||||||
| 
- Definition Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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| X | ||||||||||
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- Definition Amount of transfers of assets measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 1. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
 | 
| X | ||||||||||
| 
- References No definition available. 
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| X | ||||||||||
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- Definition Amount of transfer of financial instrument classified as an asset into (out of) level 3 of the fair value hierarchy. No definition available. 
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