LONG-TERM DEBT (Schedule of Long-term Debt) (Details) | 3 Months Ended | 9 Months Ended | | | | 28 Months Ended | | | 36 Months Ended | | | 19 Months Ended | 22 Months Ended | | | 47 Months Ended | 19 Months Ended | 22 Months Ended | | | 47 Months Ended | 19 Months Ended | 22 Months Ended | | | 47 Months Ended | 42 Months Ended | 39 Months Ended | 42 Months Ended | 0 Months Ended | 33 Months Ended | 39 Months Ended | | | | | | | | | | | | | |
Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2013 | Dec. 31, 2012 | Mar. 31, 2013 | Dec. 31, 2013 | Mar. 31, 2013 | Dec. 31, 2013 | Mar. 31, 2013 | Feb. 11, 2011 | Feb. 11, 2014 | Feb. 11, 2014 | Dec. 31, 2013 | Mar. 31, 2013 | Jun. 30, 2016 | Sep. 30, 2014 | Dec. 31, 2013 | Mar. 31, 2013 | Aug. 01, 2016 | Aug. 01, 2016 | Jun. 30, 2016 | Sep. 30, 2014 | Dec. 31, 2013 | Mar. 31, 2013 | Aug. 01, 2016 | Aug. 01, 2016 | Jun. 30, 2016 | Sep. 30, 2014 | Dec. 31, 2013 | Mar. 31, 2013 | Aug. 01, 2016 | Aug. 01, 2016 | Apr. 01, 2015 | Apr. 01, 2015 | Apr. 01, 2015 | Apr. 01, 2015 | Apr. 01, 2015 | Apr. 01, 2015 | Apr. 01, 2015 | Apr. 01, 2015 | Mar. 01, 2015 | Mar. 01, 2015 | Apr. 01, 2015 | Apr. 01, 2015 | Dec. 01, 2011 | Mar. 01, 2015 | Mar. 01, 2015 | Aug. 30, 2012 | Aug. 30, 2012 | Aug. 30, 2012 | Sep. 28, 2011 | Sep. 28, 2011 | Sep. 28, 2011 | Aug. 30, 2012 | Sep. 28, 2011 | Aug. 30, 2012 | Sep. 28, 2011 | Aug. 30, 2012 | Sep. 28, 2011 | Aug. 30, 2012 | Aug. 30, 2012 | Dec. 01, 2011 | Sep. 28, 2011 | Sep. 28, 2011 | Aug. 30, 2012 | Sep. 28, 2011 |
USD ($) | USD ($) | USD ($) | USD ($) | USD ($) | Lower Lakes Towing Ltd. [Member] | Lower Lakes Towing Ltd. [Member] | Black Creek Holdings, Inc. [Member] | Black Creek Holdings, Inc. [Member] | Black Creek Holdings, Inc. [Member] | Black Creek Holdings, Inc. [Member] | Black Creek Holdings, Inc. [Member] | Grand River Navigation Company, Inc. [Member] | Grand River Navigation Company, Inc. [Member] | Third Amended & Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Secured Debt [Member] | Secured Debt [Member] | Secured Debt [Member] | Secured Debt [Member] | Secured Debt [Member] | Secured Debt [Member] | Component 1 [Member] | Component 1 [Member] | Component 1 [Member] | Component 1 [Member] | Component 2 [Member] | Component 2 [Member] | Component 2 [Member] | Component 2 [Member] | Component 2 [Member] | Component 2 [Member] | Component 2 [Member] | Component 2 [Member] | Component 2 [Member] |
| | | | | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Lower Lakes Towing Ltd. [Member] | Lower Lakes Towing Ltd. [Member] | Lower Lakes Towing Ltd. [Member] | Lower Lakes Towing Ltd. [Member] | Lower Lakes Towing Ltd. [Member] | Lower Lakes Towing Ltd. [Member] | Black Creek Holdings, Inc. [Member] | Black Creek Holdings, Inc. [Member] | Black Creek Holdings, Inc. [Member] | Black Creek Holdings, Inc. [Member] | Black Creek Holdings, Inc. [Member] | Black Creek Holdings, Inc. [Member] | Grand River Navigation Company, Inc. [Member] | Grand River Navigation Company, Inc. [Member] | Grand River Navigation Company, Inc. [Member] | Grand River Navigation Company, Inc. [Member] | Grand River Navigation Company, Inc. [Member] | Grand River Navigation Company, Inc. [Member] | Canadian Prime Rate [Member] | Canadian BA Rate [Member] | LIBOR [Member] | US Base Rate [Member] | Lower Lakes Towing Ltd. [Member] | Lower Lakes Towing Ltd. [Member] | Lower Lakes Towing Ltd. [Member] | Lower Lakes Towing Ltd. [Member] | Lower Lakes Towing Ltd. [Member] | Lower Lakes Towing Ltd. [Member] | Grand River Navigation Company, Inc. [Member] | Grand River Navigation Company, Inc. [Member] | Grand River Navigation Company, Inc. [Member] | Grand River Navigation Company, Inc. [Member] | Grand River Navigation Company, Inc. [Member] | Third Amended & Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Revolving Credit Facility [Member] | Revolving Credit Facility [Member] | Swing Line Facility [Member] | Swing Line Facility [Member] | Revolving Credit Facility [Member] | Revolving Credit Facility [Member] | Seasonal Overadvance Facility [Member] | Seasonal Overadvance Facility [Member] | Seasonal Overadvance Facility [Member] | Seasonal Overadvance Facility [Member] | Seasonal Overadvance Facility [Member] | Swing Line Facility [Member] | Swing Line Facility [Member] |
| | | | | Canadian Term Loan [Member] | Canadian Term Loan [Member] | Black Creek US term loan [Member] | Black Creek US term loan [Member] | Black Creek US term loan [Member] | Black Creek US term loan [Member] | Black Creek US term loan [Member] | US Term Loan [Member] | US Term Loan [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | | | | | Canadian Prime Rate [Member] | Canadian BA Rate [Member] | Canadian engine loan [Member] | Canadian engine loan [Member] | Loans Payable [Member] | Loans Payable [Member] | LIBOR [Member] | US Base Rate [Member] | Loans Payable [Member] | Loans Payable [Member] | Loans Payable [Member] | Lower Lakes Towing Ltd. [Member] | Black Creek Holdings, Inc. [Member] | Grand River Navigation Company, Inc. [Member] | Lower Lakes Towing Ltd. [Member] | Lower Lakes Towing Ltd. [Member] | Grand River Navigation Company, Inc. [Member] | Third Amended & Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] | Third Amended & Restated Credit Agreement [Member] | Second Amended and Restated Credit Agreement [Member] |
| | | | | | | USD ($) | | USD ($) | LIBOR [Member] | US Base Rate [Member] | | | Canadian Term Loan [Member] | Canadian Term Loan [Member] | Canadian Term Loan [Member] | Canadian Term Loan [Member] | Canadian Term Loan [Member] | Canadian Term Loan [Member] | Black Creek US term loan [Member] | Black Creek US term loan [Member] | Black Creek US term loan [Member] | Black Creek US term loan [Member] | Black Creek US term loan [Member] | Black Creek US term loan [Member] | US Term Loan [Member] | US Term Loan [Member] | US Term Loan [Member] | US Term Loan [Member] | US Term Loan [Member] | US Term Loan [Member] | | | | | | | Canadian Prime Rate [Member] | Canadian BA Rate [Member] | Canadian Term Loan [Member] | Canadian engine loan [Member] | | | US Term Loan [Member] | US Term Loan [Member] | US Term Loan [Member] | Canadian Term Loan [Member] | Black Creek US term loan [Member] | US Term Loan [Member] | Canadian Term Loan [Member] | Canadian engine loan [Member] | US Term Loan [Member] | Lower Lakes Towing Ltd. [Member] | Lower Lakes Towing Ltd. [Member] | Lower Lakes Towing Ltd. [Member] | Lower Lakes Towing Ltd. [Member] | Lower Lakes Transportation Company [Member] | Lower Lakes Transportation Company [Member] | USD ($) | CAD | USD ($) | Lower Lakes Towing Ltd. [Member] | Lower Lakes Transportation Company [Member] | Lower Lakes Transportation Company [Member] | Lower Lakes Transportation Company [Member] |
| | | | | | | | | | | | | | CAD | CAD | USD ($) | USD ($) | Canadian Prime Rate [Member] | Canadian BA Rate [Member] | USD ($) | USD ($) | USD ($) | USD ($) | LIBOR [Member] | US Base Rate [Member] | USD ($) | USD ($) | USD ($) | USD ($) | LIBOR [Member] | US Base Rate [Member] | | | | | | | | | CAD | CAD | | | USD ($) | USD ($) | USD ($) | CAD | USD ($) | USD ($) | CAD | USD ($) | USD ($) | CAD | CAD | CAD | CAD | USD ($) | USD ($) | | | | CAD | USD ($) | USD ($) | USD ($) |
Debt Instrument [Line Items] | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Line of Credit Facility, Current Borrowing Capacity | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 13,500,000 | 13,500,000 | 4,000,000 | 4,000,000 | $13,500,000 | $13,500,000 | $12,000,000 | 12,000,000 | $12,000,000 | 10,000,000 | $10,000,000 | $50,000 | $4,000,000 |
Long-term Debt, Current and Noncurrent [Abstract] | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Long-term debt | 138,407,000 | ' | 138,407,000 | ' | 143,390,000 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 48,255,000 | 51,493,000 | ' | ' | ' | ' | 28,029,000 | 28,572,000 | ' | ' | ' | ' | 62,123,000 | 63,325,000 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Less amounts due within 12 months | 4,465,000 | ' | 4,465,000 | ' | 3,630,000 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Long-term debt, excluding current maturities | 133,942,000 | ' | 133,942,000 | ' | 139,760,000 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Basis spread on variable rate | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 4.75% | 3.75% | ' | ' | ' | ' | ' | ' | 3.75% | 4.75% | ' | ' | ' | ' | 4.75% | 3.75% | ' | ' | ' | ' | 4.75% | 3.75% | 3.50% | 4.50% | 4.50% | 3.50% | 3.50% | 4.50% | 4.00% | 5.00% | ' | ' | 4.50% | 3.50% | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Debt Instrument, Increase, Additional Borrowings | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 25,000,000 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Quarterly payment | ' | ' | ' | ' | ' | ' | ' | 517,000 | ' | ' | ' | ' | ' | ' | 662,000 | 331,000 | ' | ' | ' | ' | 362,000 | 181,000 | ' | ' | ' | ' | 802,000 | 401,000 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 936,000 | 133,000 | ' | ' | 367,000 | 704,000 | 367,000 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Effective interest rate including effect of interest rate swap contracts | ' | ' | ' | ' | ' | 6.03% | 6.03% | 4.99% | 5.88% | ' | ' | ' | 4.99% | 5.88% | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Effective interest rate | ' | ' | ' | ' | ' | 6.03% | 6.04% | 4.99% | 5.04% | ' | ' | ' | 4.99% | 5.04% | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Debt Instrument, Face Amount | ' | ' | ' | ' | ' | ' | ' | ' | ' | 31,000,000 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 52,979,000 | 28,934,000 | 64,127,000 | 56,133,000 | 6,267,000 | 17,233,000 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Loss on extinguishment of debt | $0 | $0 | $0 | $3,339,000 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |