Retirement Benefit Plans - Components of Net Periodic Benefit Cost (Details) - Pension Plan - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 78	$ 69	$ 235	$ 209
Interest cost	221	256	662	767
Expected return on plan assets	(404)	(407)	(1,211)	(1,222)
Amortization of net loss	215	210	646	630
Net periodic cost	$ 110	$ 128	$ 332	$ 384