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Subsequent Events - Additional Information (Detail) - USD ($) $ in Thousands		6 Months Ended
	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

X

- 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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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- 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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Balance Type:	na
Period Type:	duration

X

- Details

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Namespace Prefix:
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X

- Details

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Namespace Prefix:
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Balance Type:
Period Type: