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Description of Business and Basis of Presentation - Additional Information (Detail)	9 Months Ended
	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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- Definition

Formation date of company.

+ References

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- Definition

IPO completion date.

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- Definition

Number of office.

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- Definition

Percentage of company post IPO common stock distributed by the Parent company before the IPO in the IPO.

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- Definition

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.

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- Details

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