| | December 31, 2017 | | December 31, 2016 | | ||||||||
| | Changes in assumptions | | Changes in assumptions | | ||||||||
| | + 0.25% | | - 0.25% | | + 0.25% | | - 0.25% | | ||||
| | (in thousands) | | (in thousands) | | ||||||||
Discount rate | | $ | (158,160) | | | 167,594 | | | (156,764) | | | 166,453 | |
Rate of increase in future salary | | $ | 164,867 | | | (156,470) | | | 164,140 | | | (155,466) | |