XML 128 R65.htm IDEA: XBRL DOCUMENT v3.20.1
AdvisorEngine - Financial Interests carrying value of the Company's financial interests (Parenthetical) (Detail) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Mar. 31, 2020
Dec. 31, 2019
Advisor Engine [Member]    
Variable interest entity, net of an impairment $ 49,810 $ 30,138