Consolidated VIEs - Summary of Consolidated VIE Assets and Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
ASSETS
Cash and cash equivalents	$ 979,899	$ 1,389,876
Customers and other receivables	169,578	121,261
Investments	867,707	658,532
Other assets	410,285	307,332
Total Assets	6,406,800	5,971,861
Liabilities:
Deposits and other customer payables	1,228,248	1,201,150
Other liabilities	562,639	524,538
Total Liabilities	4,899,945	4,972,428
Consolidated VIEs [Member]
ASSETS
Cash and cash equivalents	4,515	3,558
Customers and other receivables	10,383	160
Investments	219,670	158,370
Other assets	836	400
Total Assets	235,404	162,488
Liabilities:
Deposits and other customer payables	10,346	104
Other liabilities	297	491
Total Liabilities	$ 10,643	$ 595