Loans - Loans by Class Modified as Troubled Debt Restructurings with Payment Default (Detail) $ in Thousands	9 Months Ended
Sep. 30, 2018 USD ($) Loan	Sep. 30, 2017 USD ($) Loan
Financing Receivable Modifications [Line Items]
Number of loans \| Loan	1	2
Recorded Investment \| $	$ 196	$ 209
Residential Mortgage Loans [Member]
Financing Receivable Modifications [Line Items]
Number of loans \| Loan	1	1
Recorded Investment \| $	$ 196	$ 162
Residential Mortgage Loans [Member] \| One-to Four-Family [Member]
Financing Receivable Modifications [Line Items]
Number of loans \| Loan	1	1
Recorded Investment \| $	$ 196	$ 162
Consumer Loans [Member]
Financing Receivable Modifications [Line Items]
Number of loans \| Loan		1
Recorded Investment \| $		$ 47
Consumer Loans [Member] \| Home Equity [Member]
Financing Receivable Modifications [Line Items]
Number of loans \| Loan		1
Recorded Investment \| $		$ 47

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- Definition

Number of financing receivables that have been modified by troubled debt restructurings within the previous 12 months and for which there was a payment default.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953682-111524

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- Definition

Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which there was a payment default.

+ References

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