Receivable from and Payable to Customers (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Receivables and Payable to Customers [Abstract]
Receivable from customers	$ 193,009	$ 105,647
Payable to customers	$ 488,814	$ 430,224

Amount due from customers for fees and charges arising from transactions related to the entity's brokerage activities and operations.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118952595&loc=d3e4428-111522

Name:	us-gaap_ReceivablesFromCustomers
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant