The following tables present the components of net periodic benefit cost (gains are denoted with parentheses and losses are not): | | | | | | | | | | | | | | | | | Nine Months Ended September 30, 2016 | (in thousands) | Hourly Employees’ Pension Plan | Employees’ Retirement Plan | | Total | Service cost | | $ | 6 |
| | | $ | 3 |
| | | $ | 9 |
| Interest cost | | 300 |
| | | 666 |
| | | 966 |
| Expected return on plan assets | | (486 | ) | | | (898 | ) | | | (1,384 | ) | Amortization of net loss | | 213 |
| | | 330 |
| | | 543 |
| Net periodic benefit cost | | $ | 33 |
| | | $ | 101 |
| | | $ | 134 |
|
| | | | | | | | | | | | | | | | | Nine Months Ended September 30, 2015 | (in thousands) | Hourly Employees’ Pension Plan | Employees’ Retirement Plan | | Total | Service cost | | $ | 6 |
| | | $ | 3 |
| | | $ | 9 |
| Interest cost | | 303 |
| | | 651 |
| | | 954 |
| Expected return on plan assets | | (495 | ) | | | (921 | ) | | | (1,416 | ) | Amortization of net loss | | 186 |
| | | 300 |
| | | 486 |
| Net periodic benefit cost | | $ | — |
| | | $ | 33 |
| | | $ | 33 |
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