Accounting for Certain Loans Acquired with Deteriorated Credit Quality - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Receivables [Abstract]
Increase in allowance recognized on purchase credit impaired loans	$ 0.1
Decrease in allowance recognized on purchase credit impaired loans		$ 0.2

Amount of reduction in the reserve for loans impairments as a result of current information and events which result in it being probable that estimated cash flows will be significantly higher than previously expected or because actual cash flows are significantly greater than cash flows previously expected for loans not accounted for as debt securities, with evidence of deterioration of credit quality since origination that was acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

No definition available.

Name:	us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAllowanceForLoanLossesDecreases1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration