Long-Term Debt - Schedule of Long-Term Debt (Details) - USD ($)	May 31, 2020	May 31, 2019
Debt Instrument [Line Items]
Total long-term debt	$ 22,781,896	$ 22,697,464
Debt issuance costs, net of amortization	(35,886)	(37,686)
Total debt, net of debt issuance costs	22,746,010	22,659,778
Less: Current portion of long-term debt	(4,416,377)	(3,030,630)
Long-term debt, net of current portion and debt issue costs	18,329,633	19,629,148
Term Loan A Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% But Not Less Than 4.0%, Maturing April 30, 2023 [Member]
Debt Instrument [Line Items]
Total long-term debt	2,459,854	3,234,947
Term Loan C Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% But Not Less Than 4.0%, Maturing August 4, 2024 [Member]
Debt Instrument [Line Items]
Total long-term debt	1,165,774	1,399,490
Term Loan D Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% But Not Less Than 4.75%, Maturing January 10, 2022 [Member]
Debt Instrument [Line Items]
Total long-term debt	1,136,455	1,744,235
Term Loan E Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% But Not Less Than 4.75%, Maturing January 10, 2022 [Member]
Debt Instrument [Line Items]
Total long-term debt	696,174	927,199
Term Loan F Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% But Not Less Than 5.25%, Maturing February 29, 2024 [Member]
Debt Instrument [Line Items]
Total long-term debt	2,752,293	3,398,247
Term Loan G Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% But Not Less Than 5.25%, Maturing April 30, 2024 [Member]
Debt Instrument [Line Items]
Total long-term debt	837,811	876,934
Revolving Loan Payable to International Bank of Commerce, Prime Rate of Interest Plus 0.5% But Not Less Than 5.5%, Due January 31, 2022 [Member]
Debt Instrument [Line Items]
Total long-term debt	2,540,000	3,205,000
Term Loan Payable by GRE to International Bank of Commerce, Interest Rate of 5.5%, Monthly Principal and Interest Payment of $27,688, Due April 30, 2023 [Member]
Debt Instrument [Line Items]
Total long-term debt	2,261,425	2,461,116
Term Note Payable to Great Western Bank, Interest Rate of 3.7%, Monthly Principal and Interest Payments of $27,593, due March 19, 2025, Secured by Certain Equipment [Member]
Debt Instrument [Line Items]
Total long-term debt	1,461,726
Paycheck Protection Program Note, Interest Rate of 1.0%, Maturing April 13, 2022 [Member]
Debt Instrument [Line Items]
Total long-term debt	3,034,000
Note Payable to Robert Rosene, 7.5% Interest, Due January 15, 2022 [Member]
Debt Instrument [Line Items]
Total long-term debt	4,253,228	4,426,631
Note Payable to First Bank, Prime Rate of Interest Plus 1.45% But Not Less Than 4.95%, Monthly Principal and Interest Payment of $30,628, Due August 21, 2021, Secured by Production Equipment [Member]
Debt Instrument [Line Items]
Total long-term debt		800,488
Other [Member]
Debt Instrument [Line Items]
Total long-term debt	$ 183,156	$ 223,177