Stockholders' Equity Exchangeable Shares and Conversion Rights (Details)	12 Months Ended
Dec. 31, 2017 shares votes
Class B Exchangeable Shares [Member]
Class of Stock [Line Items]
Common stock, votes per share	1
Exchangeable shares issued, Class A
Class of Stock [Line Items]
Common stock, votes per share	1
Common stock, conversion ratio \| shares	1

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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