Financial Guarantee Liability - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2022 USD ($) loan	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) loan	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($) loan
Guarantor Obligations
Outstanding loan balances	$ 27,200,000		$ 27,200,000		$ 25,800,000
Maximum loss potential	8,200,000		8,200,000		7,800,000
Provision (reversal) for expected credit losses	700	$ 1,100	588	$ (5,200)	(3,592)
Foreclosure
Guarantor Obligations
Outstanding loan balances	22,800		22,800
Maximum loss potential	$ 7,600		$ 7,600
Number of loans | loan	1		1
Liquidation value of loans outstanding	$ 20,000		$ 20,000
Potential loss on liquidation of loan			1,500
Delinquent
Guarantor Obligations
Outstanding loan balances	7,300		7,300		33,600
Maximum loss potential	$ 2,400		$ 2,400		$ 11,200
Number of loans | loan	1		1		2
Liquidation value of loans outstanding	$ 4,200		$ 4,200		$ 28,400
Potential loss on liquidation of loan			$ 1,100	$ 2,300
Fannie Mae DUS or Freddie TAH Loans | Maximum
Guarantor Obligations
Percentage of contingent liability of actual losses incurred on outstanding loans			33.00%