| Supplemental Guarantor Information - Additional Information (Details) | Sep. 30, 2018 | 
|---|---|
| Debt Disclosure [Abstract] | |
| Percentage of subsidiaries owned | 100.00% | 
| X | ||||||||||
| 
- References No definition available. 
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| X | ||||||||||
| 
- Definition Parent's ownership percentage of certain subsidiaries. No definition available. 
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