Commitments, Contingencies, and Uncertainties (Details) (ABF Lawsuit - Threatened Litigation [Member], USD $) In Millions, unless otherwise specified	6 Months Ended
Jun. 30, 2013
ABF Lawsuit - Threatened Litigation [Member]
Loss Contingencies [Line Items]
Loss contingency, damages sought	$ 750.0

The value (monetary amount) of the award the plaintiff seeks in the legal matter.

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