Contingencies (Details) - Potential Positive Outcome of Litigation $ in Millions	Sep. 30, 2016 USD ($) contract lawsuit
Contingencies
Number of lawsuits \| lawsuit	2
Number of long term gas contracts \| contract	2
Additional accounts receivable \| $	$ 51.0

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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