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Description of Business and Basis of Presentation - Additional Information (Detail) | 9 Months Ended
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Sep. 30, 2019 Office
Class of Stock [Line Items] |
Number of offices in the United States and Canada | 82
Formation date | 2013-06
Percentage of common stock distributed | 80.00%
IPO MMI [Member] |
Class of Stock [Line Items] |
IPO completion date | Oct. 30, 2013

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- Details
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