Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Sep. 30, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total accumulated other comprehensive loss	$ 46,421	$ 44,189
Foreign currency translation adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total accumulated other comprehensive loss	(5,383)	(4,955)
Retirement plan liability adjustment, net of tax
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total accumulated other comprehensive loss	(3,567)	(3,674)
Total accumulated other comprehensive loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total accumulated other comprehensive loss	$ (8,950)	$ (8,629)