Revenue Recognition - Narrative (Details) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2020	Dec. 31, 2019
Lessor, Lease, Description [Line Items]
Receivables from customers	$ 301	$ 460
Minimum
Lessor, Lease, Description [Line Items]
Remaining term of lease	1 year
Maximum
Lessor, Lease, Description [Line Items]
Remaining term of lease	40 years

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

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