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Summary of Significant Accounting Policies (Tables) | 12 Months Ended
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Sep. 30, 2017
Accounting Policies [Abstract] |
Schedule of goodwill and intangible assets | The table below provides detail regarding the Company's intangible assets.
| Goodwill |  | Core Deposit and Other Intangibles |  | Total
| (In thousands)
Balance at September 30, 2015 | $ | 291,503 |  |  | $ | 7,855 |  |  | $ | 299,358 |
Amortization | — |  |  | (2,369 | ) |  | (2,369 | )
Balance at September 30, 2016 | 291,503 |  |  | 5,486 |  |  | 296,989 |
Additions | 1,650 |  |  | 1,720 |  |  | 3,370 |
Amortization | — |  |  | (1,677 | ) |  | (1,677 | )
Balance at September 30, 2017 | $ | 293,153 |  |  | $ | 5,529 |  |  | $ | 298,682 |
Schedule of future amortization expense | The table below presents the estimated future amortization expense of core deposit and other intangibles for the next five years.
Fiscal Year |  | Expense
|  | (In thousands)
2018 |  | $ | 1,376 |
2019 |  | 1,324 |
2020 |  | 1,295 |
2021 |  | 457 |
2022 |  | 138 |

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- Definition Tabular disclosure of the amount of amortization expense expected to be recorded in succeeding fiscal years for finite-lived intangible assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
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