| PublishDate | 2018-01 | http://fasb.org/us-gaap/role/tin/taxonomyImplementationNote |
| Positive_XBRL_Value | Enter a positive XBRL value for cost. | http://fasb.org/us-gaap/role/tin/taxonomyImplementationNote |
| Negative_XBRL_Value | Enter a negative XBRL value for reversal of cost. | http://fasb.org/us-gaap/role/tin/taxonomyImplementationNote |
| SourceName | Improving Net Periodic Benefit Cost | http://fasb.org/srt/role/changeNote/changeNote |
| TaxonomyVersion | 2018 | http://fasb.org/srt/role/changeNote/changeNote |
| ChangeDate | 2017-03 | http://fasb.org/srt/role/changeNote/changeNote |
| ModifiedReferences | true | http://fasb.org/srt/role/changeNote/changeNote |
| Source_ASU_Number | 2017-07 | http://fasb.org/srt/role/changeNote/changeNote |