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Loans - Narrative, Troubled Debt Restructurings (Details) $ in Thousands | 3 Months Ended |
--- | --- | ---
Mar. 31, 2019 USD ($) contract | Mar. 31, 2018 loan contract | Dec. 31, 2018 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Number of relationships (contract) | contract | 2 | 0 |
Pre-modification balance | $ 2,836 |  |
Post-modification balance | 2,836 |  |
Troubled debt restructurings | $ 19,500 |  | $ 16,900
Number of TDR loans restructured that subsequently defaulted (contract) | 0 | 0 |
One-to-Four Family |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Number of relationships (contract) | contract | 1 |  |
Pre-modification balance | $ 2 |  |
Post-modification balance | $ 2 |  |
Commercial Mortgage Backed Securities |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |
Number of relationships (contract) | contract | 1 |  |
Pre-modification balance | $ 2,834 |  |
Post-modification balance | $ 2,834 |  |

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- Definition Post-modification amount of investment in financing receivables modified by troubled debt restructurings. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -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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