Mortgage Loans - Allowance for loan losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for expected credit losses, beginning of period	$ (3,426)	$ (6,107)
Reclassification to non-credit discount from the allowance for changes in payment timing expectations	310	1,225
Increase in allowance for expected credit losses for loan acquisitions during the period	0	(33)
Credit loss expense on mortgage loans	(43)	(44)
(Increase in)/reversal of allowance for expected credit losses due to (decreases)/increases in the net present value of expected cash flows	(1,112)	621
Reversal of allowance upon reclass of mortgage loans held-for-sale, net	3,868	0
Allowance for expected credit losses, end of period	$ (403)	$ (4,338)