Summary of Significant Accounting Policies - Related Party Transactions (Details) - Douglas Elliman Realty, LLC - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Transition Services Agreement
Related Party Transaction [Line Items]
Related party transaction, amounts of transaction	$ 1,050
Aviation Agreements
Related Party Transaction [Line Items]
Related party transaction, amounts of transaction	491
VIE
Related Party Transaction [Line Items]
Proceeds from commissions received	$ 900	$ 2,357

Amount of transactions with related party during the financial reporting period.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39603-107864

Name:	us-gaap_RelatedPartyTransactionAmountsOfTransaction
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration