Summary of Significant Accounting Policies - Fees Receivable (Details)	12 Months Ended
Dec. 31, 2021 USD ($)
Agent Annual Fees Receivable
Agent annual fees receivable	$ 200,000
Agent annual fees receivable, net of estimated allowances	$ 500

Amount of receivables arising from agent annual fees.

No definition available.

Name:	fthm_AgentAnnualFeesReceivableNet
Namespace Prefix:	fthm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant