LONG-TERM DEBT (Schedule of Long-term Debt) (Details) - USD ($) | Sep. 29, 2015 | Mar. 13, 2014 | Sep. 30, 2015 | Mar. 31, 2015 | Mar. 27, 2015 | Mar. 11, 2014 |
Debt Instrument [Line Items] | | | | | | |
Subordinated Debt | | | $ 78,126,000 | $ 72,500,000 | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Long-term debt | | | 118,663,000 | 101,213,000 | | |
Less amounts due within 12 months | | | 0 | 0 | | |
Long-term debt, excluding current maturities | | | 118,663,000 | 101,213,000 | | |
Fourth Amended and Restated Credit Agreement [Member] | Lower Lakes Towing Ltd. [Member] | Loans Payable [Member] | Canadian Term Loan [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Debt Instrument Periodic Payment Percentage of Initial Principal | | 1.00% | | | | |
Fourth Amended and Restated Credit Agreement [Member] | Lower Lakes Towing Ltd. [Member] | Loans Payable [Member] | Canadian Term Loan [Member] | Canadian Prime Rate [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Basis spread on variable rate | | 3.00% | | | | |
Fourth Amended and Restated Credit Agreement [Member] | Lower Lakes Towing Ltd. [Member] | Loans Payable [Member] | Canadian Term Loan [Member] | Canadian BA Rate [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Basis spread on variable rate | | 4.00% | | | | |
Fourth Amended and Restated Credit Agreement [Member] | Grand River Navigation Company, Inc. [Member] | Loans Payable [Member] | US Term Loan [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Debt Instrument Periodic Payment Percentage of Initial Principal | | 1.00% | | | | |
Fourth Amended and Restated Credit Agreement [Member] | Grand River Navigation Company, Inc. [Member] | Loans Payable [Member] | US Term Loan [Member] | LIBOR [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Basis spread on variable rate | | 4.00% | | | | |
Fourth Amended and Restated Credit Agreement [Member] | Grand River Navigation Company, Inc. [Member] | Loans Payable [Member] | US Term Loan [Member] | US Base Rate [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Basis spread on variable rate | | 3.00% | | | | |
Credit Facitities [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Debtor-in-Possession Financing, Fee on Unused Borrowings | | | | | 0.25% | |
MaximumUnusedCommitmentBeforeRateChange | | | | | 50.00% | |
Credit Facitities [Member] | Canadian Guarantors [Member] | Revolving Credit Facility [Member] | Canadian Revolving Facility [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Long-term debt | | | $ 41,963,000 | $ 44,213,000 | | |
Effective interest rate including effect of interest rate swap contracts | | | 3.75% | 3.75% | | |
Credit Facitities [Member] | US Guarantors [Member] | Revolving Credit Facility [Member] | US Revolving Facility [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Long-term debt | | | $ 76,700,000 | $ 57,000,000 | | |
Effective interest rate including effect of interest rate swap contracts | | | 3.04% | 3.03% | | |
Subordinated Debt [Member] | Lower Lakes Towing Ltd. [Member] | Second Lien Canadian Term Loan [Member] | LIBOR [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Basis spread on variable rate | | 9.50% | | | | |
Subordinated Debt [Member] | Lower Lakes Towing Ltd. [Member] | Second Lien Canadian Term Loan [Member] | US Base Rate [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Basis spread on variable rate | | 8.50% | | | | |
Subordinated Debt [Member] | Grand River Navigation Company, Inc. [Member] | Second Lien US Term Loan [Member] | LIBOR [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Basis spread on variable rate | | 9.50% | | | | |
Subordinated Debt [Member] | Grand River Navigation Company, Inc. [Member] | Second Lien US Term Loan [Member] | US Base Rate [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Basis spread on variable rate | | 8.50% | | | | |
Canada, Dollars | Fourth Amended and Restated Credit Agreement [Member] | Canadian Prime Rate [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Basis spread on variable rate | | 3.00% | | | | |
Canada, Dollars | Secured Debt [Member] | Fourth Amended and Restated Credit Agreement [Member] | Lower Lakes Towing Ltd. [Member] | Canadian Term Loan [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Debt Instrument, Face Amount | | | | | | $ 54,882,000 |
Canada, Dollars | Revolving Credit Facility [Member] | Fourth Amended and Restated Credit Agreement [Member] | Lower Lakes Towing Ltd. [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Line of Credit Facility, Current Borrowing Capacity | | | | | | 17,500,000 |
Canada, Dollars | Swing Line Facility [Member] | Fourth Amended and Restated Credit Agreement [Member] | Lower Lakes Towing Ltd. [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Line of Credit Facility, Current Borrowing Capacity | | | | | | 4,000,000 |
Canada, Dollars | Swing Line Facility [Member] | Credit Facitities [Member] | Canadian Guarantors [Member] | Revolving Credit Facility [Member] | Canadian Revolving Facility [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Line of Credit Facility, Current Borrowing Capacity | | | | | $ 8,000,000 | |
United States of America, Dollars | Lower Lakes Towing Ltd. [Member] | Second Lien Canadian Term Loan [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Subordinated Debt | | | $ 39,826,000 | $ 34,200,000 | | |
United States of America, Dollars | Grand River Navigation Company, Inc. [Member] | Second Lien US Term Loan [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Subordinated Debt | | | 38,300,000 | $ 38,300,000 | | |
United States of America, Dollars | Fourth Amended and Restated Credit Agreement [Member] | LIBOR [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Basis spread on variable rate | | 4.00% | | | | |
United States of America, Dollars | Fourth Amended and Restated Credit Agreement [Member] | US Base Rate [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Basis spread on variable rate | | 3.00% | | | | |
United States of America, Dollars | Credit Facitities [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Debt Instrument, Unused Borrowing Capacity, Amount | | | $ 30,890,000 | | | |
United States of America, Dollars | Credit Facitities [Member] | Canadian Guarantors [Member] | Revolving Credit Facility [Member] | Canadian Revolving Facility [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Line of Credit Facility, Current Borrowing Capacity | | | | | 80,000,000 | |
United States of America, Dollars | Credit Facitities [Member] | US Guarantors [Member] | Revolving Credit Facility [Member] | US Revolving Facility [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Line of Credit Facility, Current Borrowing Capacity | | | | | 90,000,000 | |
United States of America, Dollars | Secured Debt [Member] | Fourth Amended and Restated Credit Agreement [Member] | Grand River Navigation Company, Inc. [Member] | US Term Loan [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Debt Instrument, Face Amount | | | | | | 55,246,000 |
United States of America, Dollars | Subordinated Debt [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Debt Instrument, Unused Borrowing Capacity, Amount | | | | | | 32,500,000 |
United States of America, Dollars | Subordinated Debt [Member] | Lower Lakes Towing Ltd. [Member] | Second Lien Canadian Term Loan [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Debt Instrument, Face Amount | | | | | | 34,200,000 |
Proceeds from Issuance of Debt | $ 5,626,000 | | | | | |
United States of America, Dollars | Subordinated Debt [Member] | Grand River Navigation Company, Inc. [Member] | Second Lien US Term Loan [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Debt Instrument, Face Amount | | | | | | 38,300,000 |
United States of America, Dollars | Subordinated Debt [Member] | Amended Second Lien Credit Agreement [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Debt Instrument, Unused Borrowing Capacity, Amount | | | | | 22,500,000 | |
United States of America, Dollars | Revolving Credit Facility [Member] | Fourth Amended and Restated Credit Agreement [Member] | Lower Lakes Transportation Company [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Line of Credit Facility, Current Borrowing Capacity | | | | | | 17,500,000 |
United States of America, Dollars | Swing Line Facility [Member] | Fourth Amended and Restated Credit Agreement [Member] | Lower Lakes Transportation Company [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Line of Credit Facility, Current Borrowing Capacity | | | | | | 50,000 |
United States of America, Dollars | Swing Line Facility [Member] | Credit Facitities [Member] | US Guarantors [Member] | Revolving Credit Facility [Member] | US Revolving Facility [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Line of Credit Facility, Current Borrowing Capacity | | | | | $ 9,000,000 | |
Maximum [Member] | Credit Facitities [Member] | | | | | | |
Long-term Debt, Current and Noncurrent [Abstract] | | | | | | |
Debtor-in-Possession Financing, Fee on Unused Borrowings | | | | | 0.375% | |
Maximum [Member] | Canada, Dollars | Seasonal Overadvance Facility [Member] | Fourth Amended and Restated Credit Agreement [Member] | Lower Lakes Towing Ltd. [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Line of Credit Facility, Current Borrowing Capacity | | | | | | 17,500,000 |
Maximum [Member] | United States of America, Dollars | Seasonal Overadvance Facility [Member] | Fourth Amended and Restated Credit Agreement [Member] | Lower Lakes Towing Ltd. [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Line of Credit Facility, Current Borrowing Capacity | | | | | | 17,000,000 |
Maximum [Member] | United States of America, Dollars | Seasonal Overadvance Facility [Member] | Fourth Amended and Restated Credit Agreement [Member] | Lower Lakes Transportation Company [Member] | | | | | | |
Debt Instrument [Line Items] | | | | | | |
Line of Credit Facility, Current Borrowing Capacity | | | | | | $ 17,000,000 |