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Derivatives and Hedging Activities (Details) - USD ($) | 6 Months Ended |
--- | --- | ---
Mar. 31, 2017 | Mar. 31, 2016 | Sep. 30, 2016
Derivative [Line Items] |  |  |
Gain (loss) on derivative instruments | $ 0 | $ 0 |
Derivative asset, fair value, gross asset | 4,554,000 |  | $ 20,895,000
Derivative liability, fair value, gross liability | 4,060,000 |  | 55,554,000
Interest rate swap agreements |  |  |
Derivative [Line Items] |  |  |
Customer derivatives program | 925,365,000 |  | 840,935,000
Notional amount | 700,000,000 |  | 700,000,000
Commercial loan interest rate swap |  |  |
Derivative [Line Items] |  |  |
Notional amount | 52,936,000 |  | 54,155,000
Borrowings hedges | Other assets |  |  |
Derivative [Line Items] |  |  |
Derivative asset, fair value, gross asset | 319,000 |  | 0
Borrowings hedges | Other liabilities |  |  |
Derivative [Line Items] |  |  |
Derivative liability, fair value, gross liability | 0 |  | 31,347,000
Interest rate contracts | Other assets |  |  |
Derivative [Line Items] |  |  |
Derivative asset, fair value, gross asset | 4,060,000 |  | 20,895,000
Interest rate contracts | Other liabilities |  |  |
Derivative [Line Items] |  |  |
Derivative liability, fair value, gross liability | 4,060,000 |  | 20,895,000
Commercial loan hedges | Other assets |  |  |
Derivative [Line Items] |  |  |
Derivative asset, fair value, gross asset | 175,000 |  | 0
Commercial loan hedges | Other liabilities |  |  |
Derivative [Line Items] |  |  |
Derivative liability, fair value, gross liability | $ 0 |  | $ 3,312,000

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- Definition Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (a),(c) -URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624163-113959 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=51825145&loc=SL20226000-175313 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 20 -Section 50 -Paragraph 4D -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=64830801&loc=SL51823488-111719 + Details
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- Definition Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5618551-113959 + Details
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