The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

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Property, Plant and Equipment (Details Narrative) - USD ($)	9 Months Ended
	Feb. 29, 2020	Feb. 28, 2019	May 31, 2019
Property, Plant and Equipment [Line Items]
Machinery and equipment	$ 8,473,357		$ 7,861,233
Carrying value of property, plant and equipment	57,843,677		$ 53,706,523
Depreciation expense	3,911,904	$ 3,255,939
Two Plant Buildings and Land [Member]
Property, Plant and Equipment [Line Items]
Carrying value of property, plant and equipment	2,809,645
Service [Member]
Property, Plant and Equipment [Line Items]
Machinery and equipment	$ 1,680,960
Pallet Molds [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years 6 months
Material Handling Equipment [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years
Material Handling Equipment [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	7 years
Molding Machines [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	12 years