Federal Income Taxes - Summary of Net Change in Deferred Taxes (Details) - USD ($)	12 Months Ended
	May 31, 2018	May 31, 2017
Income Tax Disclosure [Abstract]
Net operating loss carryforward	$ (87,308)	$ (229,465)
Depreciation and amortization, tax reporting in excess of financial	(664,475)	(911,766)
Stock compensation costs		18,124
Allowance for doubtful accounts	(8,788)	4,280
Accrued expenses	(11,701)	113,021
Other	(108)	3,539
Net decrease	$ (772,380)	$ (1,002,267)