Shareholders' Equity - Noncontrolling Interests (Details) - SACS	12 Months Ended
Dec. 31, 2017
Noncontrolling Interest [Line Items]
Life term of contract	25 years
Percentage of profit share of parent in joint venture	88.75%
Percentage of profit share of noncontrolling in joint venture	11.25%

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.

No definition available.

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