NOTES PAYABLE AND LONG-TERM DEBT - Narrative (Details)	Mar. 29, 2017 USD ($)	Mar. 31, 2018 USD ($)
Line of Credit Facility [Line Items]
Borrowings outstanding		$ 2,152,000
Performance bonds
Line of Credit Facility [Line Items]
Performance bonds outstanding, financial assurance		600,000.0
Unsecured Note Payable
Line of Credit Facility [Line Items]
Borrowings outstanding		41,000
Term Loan
Line of Credit Facility [Line Items]
Borrowings outstanding		$ 2,111,000
Maturity period	5 years
Interest rate		4.25%
Credit Agreement
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 14,000,000.0
Percentage of eligible accounts receivable considered for borrowing base	80.00%
Percentage of eligible inventory considered for borrowing base	50.00%
Borrowing base, monetary benchmark	$ 3,000,000
Basis spread of variable rate	0.00%
Unused capacity, commitment fee percentage	0.25%
Remaining borrowing capacity		$ 11,800,000
Credit Agreement | Minimum
Line of Credit Facility [Line Items]
Debt service coverage ratio	1.15
Credit Agreement | Maximum
Line of Credit Facility [Line Items]
Debt cash flow leverage ratio	3.0
Credit Agreement | Working Capital
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 6,000,000.0
Remaining borrowing capacity		6,000,000
Credit Agreement | Letter of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity	2,000,000.0
Amount outstanding		40,000
Credit Agreement | Acquisitions
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 8,000,000.0
Percentage of portion allocated to acquisition purchase price	75.00%
Remaining borrowing capacity		$ 5,800,000
Credit Agreement | LIBOR
Line of Credit Facility [Line Items]
Basis spread of variable rate	2.50%
Debt instrument, term of variable rate	1 month
Credit Agreement | LIBOR | Maximum
Line of Credit Facility [Line Items]
Basis spread of variable rate	3.00%