Financial Guarantee Liability - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024 USD ($) loan	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) loan	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) loan	Dec. 31, 2022 USD ($)
Guarantor Obligations
Outstanding loan balances	$ 31,000,000		$ 31,000,000		$ 29,100,000
Maximum loss potential	9,600,000		9,600,000		9,000,000
Provision (reversal) for expected credit losses	(2,700)	$ 800	$ (1,317)	$ 3,400	2,634
Delinquency threshold period			60 days
Financial guarantee liability, settlement loss			$ 300		1,200
Financial guarantee liability, settlement loss, write off						$ 600
Delinquent
Guarantor Obligations
Outstanding loan balances	5,100		5,100		7,300
Maximum loss potential	$ 1,700		$ 1,700		2,400
Number of loans | loan	1		1
Advances for principal and interest	$ 1,800		$ 1,800
Liquidation value of loans outstanding	$ 6,100		6,100		7,500
Potential loss on liquidation of loan			$ 100		$ 500
Foreclosure
Guarantor Obligations
Number of loans | loan					1
Fannie Mae DUS or Freddie TAH Loans | Maximum
Guarantor Obligations
Percentage of contingent liability of actual losses incurred on outstanding loans			33.00%