Pension and Postretirement Benefits (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Sep. 30, 2020	Mar. 31, 2020	Mar. 31, 2019
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	$ 316		$ 1,174
Defined Benefit Plan, Interest Cost	1,090		1,769
Defined Benefit Plan, Expected Return on Plan Assets	(2,082)		(1,959)
Defined Benefit Plan, Settlement Charge	0		22,667
Defined Benefit Plan, Amortization of Losses	855		1,047
Defined Benefit Plan, Amortization of Prior Service Cost	2		(40)
Defined Benefit Plan, Net Periodic Benefit Cost	181		24,658
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year	10,000
Defined Benefit Plan, Contributions by Employer	1,000
Defined Benefit Plan Effect Of Settlements And Curtailments On Accumulated Benefit Obligation			22,700
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	1		2
Defined Benefit Plan, Interest Cost	11		26
Defined Benefit Plan, Expected Return on Plan Assets	0		0
Defined Benefit Plan, Settlement Charge	0		0
Defined Benefit Plan, Amortization of Losses	0		15
Defined Benefit Plan, Amortization of Prior Service Cost	0		0
Defined Benefit Plan, Net Periodic Benefit Cost	12		$ 43
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year	300
Defined Benefit Plan, Contributions by Employer	$ 100
Legacy Quaker [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Settlement Charge				$ (22,700)
Defined benefit plan settlement [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Contributions by Employer		$ 1,800