Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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The total charge for the use of long-lived depreciable assets subject to a lease meeting the criteria for capitalization.

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Amount of expense charged against earnings to allocate the cost of tangible and intangible assets over their remaining economic lives, classified as other.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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No definition available.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Property, Plant and Equipment (Details) - USD ($) $ in Thousands	6 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Apr. 30, 2018
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 454,939		$ 444,634
Less accumulated amortization and depreciation	(241,516)		(226,532)
Property, Plant and Equipment, Net, Total	213,423		218,102
Amortization and depreciation expense on property, plant and equipment	9,000	$ 4,000
Accumulated amortization on capital leases	30,700		30,000
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	4,751		4,751
Buildings and improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	112,620		112,757
Buildings and improvements - capital leases
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	11,202		11,202
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	284,533		274,723
Machinery and equipment - capital leases
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	31,003		30,270
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 10,830		$ 10,931