Annual report pursuant to Section 13 and 15(d)

Annual report pursuant to Section 13 and 15(d)

Segment Information - Additional Information (Detail)

v3.8.0.1
Segment Information - Additional Information (Detail) - Segment
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Segment Reporting [Abstract]    
Number of operating segments 2 1