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Summary of Significant Accounting Policies Summary of Significant Accounting Policies - Earnings Per Share (Details) | 3 Months Ended
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Mar. 31, 2018 shares
Accounting Policies [Abstract] |
Number of shares of Common stock received for each exchangeable share (in shares) | 1

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- Definition Number of shares of common stock received for each exchangeable share. + References No definition available. + Details
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Balance Type: | na
Period Type: | duration

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- References No definition available. + Details
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