Off-Balance-Sheet Risk and Concentration of Credit Risk (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Off-Balance-Sheet Risk and Concentration of Credit Risk [Abstract]
Receivables from clearing brokers	$ 23,086	$ 24,068

Amount of right to receive cash and securities on deposit with clearing organizations. Clearing organizations perform post trade processing and trade comparisons among numerous broker-dealers and act as settlement agents between buying and selling broker-dealers.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 940
-SubTopic 310
-URI http://asc.fasb.org/subtopic&trid=2176284

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