Derivative and Other Financial Instruments with Off-Balance Sheet Risks - Summary of the recourse liability (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	9 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Summary Of Recourse Liability [Roll Forward]
Balance, beginning of the period			$ 250	$ 250	$ 283
Provision (recovery) from recourse liability	$ 0	$ 0	0	0	(33)
Net settlements in lieu of loan repurchases	0	0	$ 0	0	0
Balance, end of the period	$ 250	$ 250		$ 250	$ 250

Amount represents the difference between the cash acquisition price of the debt and the net carrying amount of the debt at the time of its extinguishment.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=117329964&loc=d3e12355-112629

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=117329964&loc=d3e12317-112629

Name:	us-gaap_GainsLossesOnRecourseDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration