LEGAL PROCEEDINGS, ENVIRONMENTAL MATTERS, AND OTHER EVENTS (Details) (Environmental Matters, USD $) In Millions, unless otherwise specified	6 Months Ended
Jun. 30, 2013 state tank	Dec. 31, 2012
Environmental Matters
Loss contingencies
Number of underground tanks where the company's subsidiaries store fuel for use in tractors and trucks	67
Number of states in which underground tanks are located	22
Estimated environmental cleanup costs of properties currently or previously operated by the company	$ 0.9	$ 0.9

Carrying value of the obligation (known or estimated) arising from requirements to perform activities to remediate one or more sites, payable in twelve months or in the next operating cycle if longer.

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