Employee Benefit Plans - Narrative (Details)
|
3 Months Ended |
9 Months Ended |
12 Months Ended |
|
Dec. 31, 2016
USD ($)
|
Sep. 30, 2016
USD ($)
entrant
|
Sep. 30, 2015
USD ($)
|
Sep. 30, 2016
USD ($)
entrant
|
Sep. 30, 2015
USD ($)
|
Dec. 31, 2017
USD ($)
|
| Defined Benefit Plan Disclosure [Line Items] |
|
|
|
|
|
|
| Number of new entrants after pension plans were frozen | entrant |
|
0
|
|
0
|
|
|
| Employer contributions to the pension plans |
|
$ 1,900,000
|
$ 0
|
$ 1,900,000.0
|
$ 0
|
|
| Increase in pension liability |
|
|
|
900,000
|
|
|
| Settlement charge |
|
|
|
1,200,000
|
900,000
|
|
| Deferred actuarial loss |
|
|
|
900,000
|
|
|
| Accumulated benefits |
|
|
|
2,700,000
|
|
|
| Minimum | Forecast |
|
|
|
|
|
|
| Defined Benefit Plan Disclosure [Line Items] |
|
|
|
|
|
|
| Settlement charge |
$ (100,000)
|
|
|
|
|
|
| Unrecognized actuarial losses |
|
|
|
|
|
$ 16,000,000
|
| Accumulated benefits |
|
|
|
|
|
4,000,000
|
| Maximum | Forecast |
|
|
|
|
|
|
| Defined Benefit Plan Disclosure [Line Items] |
|
|
|
|
|
|
| Settlement charge |
$ (200,000)
|
|
|
|
|
|
| Unrecognized actuarial losses |
|
|
|
|
|
19,000,000
|
| Accumulated benefits |
|
|
|
|
|
$ 6,000,000
|
| Other Post-Retirement Benefits |
|
|
|
|
|
|
| Defined Benefit Plan Disclosure [Line Items] |
|
|
|
|
|
|
| Net period benefit costs |
|
|
100,000
|
100,000
|
100,000
|
|
| Expected employer contributions for current year |
|
|
|
200,000
|
|
|
| Pension Benefits |
|
|
|
|
|
|
| Defined Benefit Plan Disclosure [Line Items] |
|
|
|
|
|
|
| Net period benefit costs |
|
$ 1,200,000
|
1,100,000
|
1,200,000
|
1,200,000
|
|
| Settlement charge |
|
|
$ 900,000
|
$ 1,200,000
|
$ 900,000
|
|