Fair Value: Schedule of balances of assets and liabilities, measured at fair value on a non-recurring basis (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative fair value asset	$ 1,203,000	$ 1,662,000
Impaired loans (included in loans receivable, net)	7,913,000	10,087,000
OREO	454,000	483,000	$ 483,000	$ 483,000
Total, Fair Value	8,367,000	10,570,000
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative fair value asset	0	0
Impaired loans (included in loans receivable, net)	0	0
OREO	0	0
Total, Fair Value	0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative fair value asset	1,203,000	1,662,000
Impaired loans (included in loans receivable, net)	0	0
OREO	0	0
Total, Fair Value	0	0
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative fair value asset	0	0
Impaired loans (included in loans receivable, net)	7,913,000	10,087,000
OREO	454,000	483,000
Total, Fair Value	$ 8,367,000	$ 10,570,000