Recently Issued Accounting Standards (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Recently Issued Accounting Pronouncements
Cost of goods sold	$ 107,857	$ 97,751	$ 316,382	$ 275,062
Nonoperating retirement benefit expense	$ 856	2,118	$ 2,568	6,289
Reclassification upon adoption | ASU 2017-07
Recently Issued Accounting Pronouncements
Cost of goods sold		(2,118)		(6,289)
Nonoperating retirement benefit expense		$ 2,118		$ 6,289