Components of Periodic Benefit Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Change in funded status of benefit plans	$ 9,100
Pension
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	1,780	$ 1,905
Interest cost	2,129	2,111
Expected return on plan assets	(4,815)	(6,202)
Amortization of prior service cost	0	0
Amortization of Net loss	707	2,750
Net periodic cost (income)	(199)	564
RIM
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	61	59
Interest cost	111	107
Expected return on plan assets	0	0
Amortization of prior service cost	0	0
Amortization of Net loss	103	113
Net periodic cost (income)	275	279
Post-retirement
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	93	118
Interest cost	205	186
Expected return on plan assets	0	0
Amortization of prior service cost	(34)	(34)
Amortization of Net loss	69	81
Net periodic cost (income)	$ 333	$ 351