Quarterly report pursuant to Section 13 or 15(d)

Quarterly report pursuant to Section 13 or 15(d)

Nature of Business and Basis of Presentation (Detail)

v3.19.1
Nature of Business and Basis of Presentation (Detail) - segment
3 Months Ended 12 Months Ended
Mar. 31, 2019
Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]    
Number of operating segments 2  
Percentage of consolidated assets net revenues and net income reported by reportable operating segment 100.00% 100.00%