| Standard label: | Tubular Goods [Member] | 
| Name: | us-gaap:PublicUtilitiesInventoryTubularGoodsMember | 
| Documentation: | Pipe and tube products used in the exploration and development of energy resources. Examples include, but are not limited to, drill pipe, pipe casings and oil pipes. | 
| Object type: | cm:Member | 
| Data type: | [Member] (nonnum:domainItemType) | 
| Period type: | For Period (duration) | 
| Balance type: | (no balance type) | 
| Abstract: | true | 
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:PublicUtilitiesInventoryTubularGoodsMember | 
| Label | Role | Language | 
| Tubular Goods [Member] | http://www.xbrl.org/2003/role/label | en-US | 
| Reference | Role | Topic | 
| FASB Accounting Standards Codification 210 10 S99 1 (SX 210.5-02(6)(a)(5)) | http://fasb.org/us-gaap/role/ref/legacyRef | 210 |