Annual report pursuant to Section 13 and 15(d)

Description of Business and Basis of Presentation - Additional Information (Detail)

v3.8.0.1
Description of Business and Basis of Presentation - Additional Information (Detail)
12 Months Ended
Dec. 31, 2017
Office
Class of Stock [Line Items]  
Number of offices in the United States and Canada 78
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