Loans Held for Investment - Schedule of loan forbearance related to COVID-19 hardship requests (Details)	12 Months Ended
	Jun. 30, 2021 USD ($) loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Forbearance Granted, Number of Loans | loan	67
Forbearance Granted, Amount	$ 27,872,000
Forbearance Completed, Number of Loans | loan	63
Forbearance Completed, Amount	$ 26,030,000
Forbearance Remaining, Number of Loans | loan	4
Forbearance Remaining, Amount	$ 1,842,000
% of Total Loans	0.22%
Weighted Avg. LTV	61.00%
Weighted Avg. FICO	727
Weighted Avg. Debt Coverage Ratio	1.53
Weighted Avg. Forbearance Period Granted	8 years 10 months 24 days
Number of forbearance loans subsequently extended | loan	19
Amount of forbearance loans subsequently extended	$ 7,100,000
Mortgage loans, Single-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Forbearance Granted, Number of Loans | loan	59
Forbearance Granted, Amount	$ 23,551,000
Forbearance Completed, Number of Loans | loan	56
Forbearance Completed, Amount	$ 22,654,000
Forbearance Remaining, Number of Loans | loan	3
Forbearance Remaining, Amount	$ 897,000
% of Total Loans	0.11%
Weighted Avg. LTV	78.00%
Weighted Avg. FICO	696
Weighted Avg. Forbearance Period Granted	14 years
Value of pending requests for payment relief	$ 0
Mortgage Loans, Multi Family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Forbearance Granted, Number of Loans | loan	5
Forbearance Granted, Amount	$ 2,321,000
Forbearance Completed, Number of Loans | loan	5
Forbearance Completed, Amount	$ 2,321,000
Mortgage loans, Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Forbearance Granted, Number of Loans | loan	3
Forbearance Granted, Amount	$ 2,000,000
Forbearance Completed, Number of Loans | loan	2
Forbearance Completed, Amount	$ 1,055,000
Forbearance Remaining, Number of Loans | loan	1
Forbearance Remaining, Amount	$ 945,000
% of Total Loans	0.11%
Weighted Avg. LTV	48.00%
Weighted Avg. FICO	704
Weighted Avg. Debt Coverage Ratio	1.71
Weighted Avg. Forbearance Period Granted	4 years