Pension and Post-retirement Benefits (Tables)

6 Months Ended

Mar. 31, 2020

Pension and Post-retirement Benefits

Schedule of components of net periodic pension and postretirement benefit cost

	Three Months Ended March 31,								Six Months Ended March 31,
	Pension Benefits				Other Benefits				Pension Benefits				Other Benefits
	2019		2020		2019		2020		2019		2020		2019		2020
Service cost	$	1,310	$	1,387	$	79	$	354	$	2,620	$	2,773	$	158	$	708
Interest cost		2,567		2,148		1,088		873		5,133		4,296		2,176		1,746
Expected return		(3,575)		(3,623)		—		—		(7,147)		(7,268)		—		—
Amortizations		401		1,859		372		462		803		3,718		744		924
Net periodic benefit cost	$	703	$	1,771	$	1,539	$	1,689	$	1,409	$	3,519	$	3,078	$	3,378