Commitments and Contingencies - Environmental Laws and Regulations - Additional Information (Detail) |
6 Months Ended |
|---|---|
|
Jun. 30, 2016
USD ($)
| |
| Loss Contingencies [Line Items] | |
| Penalties imposed on inspections | $ 100,000 |
| Minimum [Member] | Natrium West Virginia And Lake Charles South Facility [Member] | |
| Loss Contingencies [Line Items] | |
| Period during which facilities are operational | 65 years |