Pension and Post-retirement Benefits (Tables)

6 Months Ended

Mar. 31, 2018

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
	2017		2018		2017		2018		2017		2018		2017		2018
Service cost	$	1,570	$	1,384	$	87	$	84	$	3,141	$	2,768	$	174	$	168
Interest cost		2,592		2,625		1,073		1,078		5,141		5,231		2,146		2,156
Expected return		(3,531)		(3,665)		—		—		(7,003)		(7,299)		—		—
Amortizations		2,994		1,294		1,070		751		5,975		2,583		2,140		1,500
Net periodic benefit cost	$	3,625	$	1,638	$	2,230	$	1,913	$	7,254	$	3,283	$	4,460	$	3,824