Property, Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Property, Plant and Equipment, Net, by Type [Abstract]
Total property, plant and equipment	$ 727,514	$ 695,226
Less: accumulated depreciation	(372,743)	(333,159)
Net property, plant and equipment	354,771	362,067	$ 276,818
Depreciation expense	48,210	39,929	$ 37,584
Land and land improvements
Property, Plant and Equipment, Net, by Type [Abstract]
Total property, plant and equipment	37,421	36,775
Buildings
Property, Plant and Equipment, Net, by Type [Abstract]
Total property, plant and equipment	195,252	166,907
Machinery and equipment
Property, Plant and Equipment, Net, by Type [Abstract]
Total property, plant and equipment	352,014	280,432
Vehicles
Property, Plant and Equipment, Net, by Type [Abstract]
Total property, plant and equipment	20,075	18,719
Furniture and fixtures
Property, Plant and Equipment, Net, by Type [Abstract]
Total property, plant and equipment	10,045	9,865
Information systems
Property, Plant and Equipment, Net, by Type [Abstract]
Total property, plant and equipment	66,723	56,573
Finance leases
Property, Plant and Equipment, Net, by Type [Abstract]
Total property, plant and equipment	2,442	2,514
Construction in progress
Property, Plant and Equipment, Net, by Type [Abstract]
Total property, plant and equipment	$ 43,542	$ 123,441