Recent Accounting Pronouncements (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Jul. 01, 2020	Sep. 30, 2019	Jun. 30, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member	us-gaap:AccountingStandardsUpdate201613Member
Assets
ACL on commercial paper			$ 0
ACL on loans	$ (43,132)	$ (28,072)	(28,072)	$ (21,314)	$ (21,429)
Deferred income taxes	19,209	16,334	16,334
Liabilities
Liability for credit losses on off-balance sheet credit exposures	2,288		0
Equity:
Retained earnings	234,023	242,776	242,776
Cumulative Effect, Period of Adoption, Adjusted Balance
Assets
ACL on commercial paper			(250)
ACL on loans			(42,881)
Deferred income taxes			20,323
Liabilities
Liability for credit losses on off-balance sheet credit exposures			2,288
Equity:
Retained earnings			229,418
Cumulative-effect adjustment due to the adoption of ASU 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Additional ACL on financial instruments			15,059
Assets
ACL on commercial paper			(250)
ACL on loans		(14,809)	(14,809)
Deferred income taxes			3,989
Liabilities
Liability for credit losses on off-balance sheet credit exposures			2,288
Equity:
Retained earnings			(13,358)
Retail Consumer Loans
Assets
ACL on loans	(17,933)	(6,956)	(6,956)	(5,728)	(6,419)
Retail Consumer Loans | Cumulative Effect, Period of Adoption, Adjusted Balance
Assets
ACL on loans			(17,692)
Retail Consumer Loans | Cumulative-effect adjustment due to the adoption of ASU 2016-13
Assets
ACL on loans		(10,736)	(10,736)
Commercial Loans
Assets
ACL on loans	$ (25,199)	(21,116)	(21,116)	$ (15,392)	$ (14,809)
Commercial Loans | Cumulative Effect, Period of Adoption, Adjusted Balance
Assets
ACL on loans			(25,189)
Commercial Loans | Cumulative-effect adjustment due to the adoption of ASU 2016-13
Assets
ACL on loans		$ (4,073)	$ (4,073)