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Subsequent Events - Additional Information (Detail) - USD ($) $ in Thousands |  | 6 Months Ended
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Jul. 28, 2017 | Jun. 30, 2017 | Jun. 30, 2016
Subsequent Event [Line Items] |  |  |
Proceeds from sale of mortgage-related assets |  | $ 1,275,991 | $ 1,927,800
Subsequent Event | One-to-four family |  |  |
Subsequent Event [Line Items] |  |  |
Proceeds from sale of mortgage-related assets | $ 1,900,000 |  |

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- Definition The cash inflow resulting from the sale of loans classified as held-for-sale, including proceeds from loans sold through mortgage securitization. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 16 -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3337-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 21 -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3461-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 230 -Section 55 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=82926135&loc=d3e60097-112785 + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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- Definition Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event. + References No definition available. + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Details
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Namespace Prefix: |
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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |