Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total accumulated other comprehensive loss	$ 48,595	$ 50,131
Foreign currency translation adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total accumulated other comprehensive loss	(3,776)	(4,607)
Retirement plan liability adjustment, net of tax
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total accumulated other comprehensive loss	(4,325)	(4,648)
Interest rate swap agreement adjustment, net of tax
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total accumulated other comprehensive loss	23	4
Total accumulated other comprehensive loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total accumulated other comprehensive loss	$ (8,078)	$ (9,251)