Loans Receivable: Troubled Debt Restructurings on Financing Receivables (Details) $ in Thousands	12 Months Ended
Dec. 31, 2017 USD ($) loan	Dec. 31, 2016 USD ($) loan
Financing Receivable, Modifications [Line Items]
Number of Loans \| loan	9	26
Pre-Modification Outstanding Recorded Investment	$ 3,383	$ 6,392
Post-Modification Outstanding Recorded Investment	$ 3,383	$ 6,392
One-to-four family residential \| Principal and Interest with Interest Rate Concession
Financing Receivable, Modifications [Line Items]
Number of Loans \| loan	8	19
Pre-Modification Outstanding Recorded Investment	$ 2,492	$ 4,265
Post-Modification Outstanding Recorded Investment	$ 2,492	$ 4,265
One-to-four family residential \| Advancement of Maturity Date
Financing Receivable, Modifications [Line Items]
Number of Loans \| loan	0	5
Pre-Modification Outstanding Recorded Investment	$ 0	$ 1,121
Post-Modification Outstanding Recorded Investment	$ 0	$ 1,121
Commercial Real Estate \| Advancement of Maturity Date
Financing Receivable, Modifications [Line Items]
Number of Loans \| loan	1	1
Pre-Modification Outstanding Recorded Investment	$ 891	$ 511
Post-Modification Outstanding Recorded Investment	$ 891	$ 511
Commercial Real Estate \| Interest only payments
Financing Receivable, Modifications [Line Items]
Number of Loans \| loan	0	1
Pre-Modification Outstanding Recorded Investment	$ 0	$ 495
Post-Modification Outstanding Recorded Investment	$ 0	$ 495

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Number of financing receivables that have been 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=66008989&loc=SL6953676-111524

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Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

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Pre-modification amount of investment in financing receivables modified by troubled debt restructurings.

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