Retirement Plans and Other Post Retirement Benefits - Narrative (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Other Post Retirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected employer contributions for next fiscal year		$ 94
Defined benefit plan, contributions by employer	$ 81
Defined benefit plan, benefits paid	81
Nonqualified Plan [Member] | Retirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected employer contributions for next fiscal year		$ 156
Defined benefit plan, contributions by employer	117
Defined benefit plan, benefits paid	$ 2,000