Equity - Common Stock Continuous Offering Program (Details) - Common Stock [Member] - USD ($)	Dec. 31, 2017	Sep. 19, 2016
Class of Stock [Line Items]
Distribution agreement gross sales price (up to)		$ 750,000,000
Distribution agreement stock issued	$ 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.

No definition available.

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