Fair Value: Schedule of quantitative information about Level 3 Fair Value Measurements on a nonrecurring basis (Details) - Level 3 - Market Approach Valuation Technique - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2018	Dec. 31, 2017
Loans Receivable
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Fair Value	$ 16,327	$ 17,849
Fair Value Measurements, Valuation Techniques	Market approach	Market approach
Unobservable Input(s)	Appraised value discounted by market or borrower conditions	Appraised value discounted by market or borrower conditions
Loans Receivable \| Minimum
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Fair value of financial instruments, range	0.00%	0.00%
Loans Receivable \| Maximum
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Fair value of financial instruments, range	0.00%	0.00%
Loans Receivable \| Weighted Average
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Fair value of financial instruments, range	0.00%	0.00%
Other Real Estate Owned
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Fair Value	$ 483	$ 483
Fair Value Measurements, Valuation Techniques	Market approach	Market approach
Unobservable Input(s)	Appraised value less selling costs	Appraised value less selling costs
Other Real Estate Owned \| Minimum
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Fair value of financial instruments, range	0.00%	0.00%
Other Real Estate Owned \| Maximum
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Fair value of financial instruments, range	0.00%	0.00%
Other Real Estate Owned \| Weighted Average
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation
Fair value of financial instruments, range	0.00%	0.00%

The percent range of asset measurement values for fair value disclosure.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Description of the valuation processes in place for fair value measurements categorized within Level 3 of the fair value hierarchy.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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Description of the inputs and valuation technique(s) used to measure fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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- Definition

Aggregation of the liabilities reported on the balance sheet measured at fair value on a nonrecurring basis by the entity.

+ References

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