Retirement Benefit Plans - Narrative (Details) |
12 Months Ended | ||
---|---|---|---|
Sep. 30, 2020
USD ($)
plan
|
Sep. 30, 2019
USD ($)
|
Jan. 01, 2020
USD ($)
|
|
Defined Benefit Plan Disclosure [Line Items] | |||
Number of defined benefit pension plans | plan | 4 | ||
Employer contributions | $ 245,000 | ||
Plan funded percentage | 89.00% | ||
Other debt withdrawal liability | $ 739,000 | ||
Employer matching contribution percentage of employees' gross pay | 100.00% | ||
Percentage of eligible compensation of deferral contribution, minimum | 1.00% | ||
Percentage of eligible compensation | 80.00% | ||
Percentage of eligible compensation of deferral contribution, maximum | 6.00% | ||
Matching contribution expense for defined contribution plan | $ 648,000 | $ 470,000 | |
Non-elective contribution per hour | $ 1.50 | ||
Non-elective contribution expense | $ 56,000 | ||
IAM National Pension Fund | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Payment period | 20 years |