INVESTMENT IN TERMINAL JOINT VENTURE (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Investments in affiliates
Investment in related party Terminal Joint Venture	$ 66.4	$ 64.4
Financial information for equity method investment
Company Share of Net Income (Loss)	16.5	6.6	$ (2.0)
Distributions Received	14.0
Current assets	107.0	80.7
Noncurrent assets	121.2	140.9
Total assets	228.2	221.6
Current liabilities	42.0	40.9
Noncurrent liabilities	9.4	7.1
Equity	176.8	173.6
Total Liabilities and Equity	228.2	221.6
Operating revenue	621.0	586.2	498.4
Operating costs and expenses	610.2	589.7	517.4
Operating Income (loss)	10.8	(3.5)	(19.0)
Net Income (Loss)	$ 44.9	21.2	(5.7)
SSAT | Ocean Transportation
Investments in affiliates
Ownership interest accounted in the related party terminal joint venture (as a percent)	35.00%
Cost of services from transactions with unconsolidated affiliate	$ 174.1	164.8	$ 164.3
Accounts payable and accrued liabilities	$ 19.5	$ 17.5