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Loans Receivable - Additional Information (Details) - USD ($) $ in Thousands | 3 Months Ended |
--- | --- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Sep. 30, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Nonaccrual interest income recognized | $ 2,551 |  |
Impaired, interest lost on nonaccrual loans | $ 489 |  |
Ratio of past due loans to total loans, net of charge-offs and LIPs | 0.43% |  | 0.40%
Percent of TDRs classified as performing | 97.60% |  |
Troubled debt restructuring, amount | $ 9,268 | $ 2,566 |
Basis point reduction, minimum | 1.00% |  |
Basis point reduction, maximum | 2.00% |  |
Single family residential loans as percentage of restructured loans | 85.70% |  |
Covered assets | $ 58,699 |  | $ 67,914
Loans receivable, gross | 12,456,216 |  | 12,201,387
FDIC indemnification asset | 0 |  | 8,967
FDIC clawback liability | 39,906 |  | 37,143
FDIC loss share valuation adjustments | (8,550) | $ 0 |
Covered loans |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Loans receivable, gross | $ 54,865 |  | $ 61,810
Minimum |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Term for payment and rate reduction | 6 months |  |
Maximum |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Term for payment and rate reduction | 24 months |  |
Performing Loans |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Troubled debt restructuring, amount | $ 199,175 |  |

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- Definition Change in carrying amount of the indemnification asset relating to loss sharing agreements with the Federal Deposit Insurance Corporation (FDIC). The change includes for example, but is not limited to, acquisitions, additional estimated losses, disposals, cash payments, accretion of discount and write-offs, net of recoveries. + References No definition available. + Details
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- Definition Post-modification amount of investment in financing receivables modified by troubled debt restructurings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953676-111524 + Details
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- Definition Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522 + Details
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- Definition Reflects the amount of additional interest income that would have been recorded if impaired or nonperforming loans were instead current, in compliance with their original terms, and outstanding throughout the reporting period or since origination (if held for part of the period). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 40 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=82895541&loc=d3e18794-111554 + Details
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