Interest Receivable (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest receivable	$ 53,799	$ 48,857
Loans receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest receivable	48,704	41,429
Mortgage-backed securities
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest receivable	3,071	6,107
Investment securities
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest receivable	$ 2,024	$ 1,321

Interest, dividends, rents, ancillary and other revenues earned but not yet received by the entity on its investments.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(4))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(10))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Name:	us-gaap_AccruedInvestmentIncomeReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant