FIRST FINANCIAL NORTHWEST, INC. AND SUBSIDIARIES CONSOLIDATED STATEMETNS OF STOCKHOLDERS' EQUITY (PARENTHETICALS) - $ / shares	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Stockholders' Equity [Abstract]
Dividends (usd per share)	$ 0.10	$ 0.09	$ 0.20	$ 0.17
Allocated shares	28,214	28,213	56,428	56,426

Number of shares of capital stock issued (purchased by employees) in connection with an employee stock ownership plan.

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Period Type:	duration