Business Combinations - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands		12 Months Ended
Oct. 01, 2018	Sep. 30, 2019
Business Acquisition [Line Items]
Goodwill recognized		$ 9,481
South Sound Merger
Business Acquisition [Line Items]
Total merger consideration	$ 35,170
Goodwill recognized	9,481
Book Value \| South Sound Merger
Business Acquisition [Line Items]
Cash and cash equivalents	21,187
CDs held for investment	2,973
FHLB stock	205
Investment securities held to maturity	19,891
Investment securities available for sale	5,022
Loans receivable	123,627
Premises and equipment	3,225
OREO	25
Accrued interest receivable	554
BOLI	2,629
CDI	0
MSRs	285
Other assets	1,087
Total assets	180,710
Deposits	151,378
Other liabilities and accrued expenses	3,291
Total liabilities assumed	154,669
Total identifiable net assets acquired	26,041
Fair Value Adjustment \| South Sound Merger
Business Acquisition [Line Items]
Cash and cash equivalents	0
CDs held for investment	0
FHLB stock	0
Investment securities held to maturity	(189)
Investment securities available for sale	0
Loans receivable	(2,083)
Premises and equipment	112
OREO	0
Accrued interest receivable	0
BOLI	0
CDI	2,483
MSRs	(4)
Other assets	(511)
Total assets	(192)
Deposits	160
Other liabilities and accrued expenses	0
Total liabilities assumed	160
Total identifiable net assets acquired	(352)
Estimated Fair Value \| South Sound Merger
Business Acquisition [Line Items]
Total merger consideration	35,170
Cash and cash equivalents	21,187
CDs held for investment	2,973
FHLB stock	205
Investment securities held to maturity	19,702
Investment securities available for sale	5,022
Loans receivable	121,544
Premises and equipment	3,337
OREO	25
Accrued interest receivable	554
BOLI	2,629
CDI	2,483
MSRs	281
Other assets	576
Total assets	180,518
Deposits	151,538
Other liabilities and accrued expenses	3,291
Total liabilities assumed	154,829
Total identifiable net assets acquired	25,689
Goodwill recognized	$ 9,481

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Accrued Interest Receivable

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Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, BOLI

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Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Core Deposits

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Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Mortgage Servicing Rights

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), classified as noncurrent.

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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Amount of assets acquired at the acquisition date.

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Amount of currency on hand as well as demand deposits with banks or financial institutions, acquired at the acquisition date. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Amount of investments in debt and equity securities, including, but not limited to, held-to-maturity, trading and available-for-sale expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer, acquired at the acquisition date.

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Amount due from customers or clients for goods or services, including trade receivables, that have been delivered or sold in the normal course of business, and amounts due from others, including related parties expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer, acquired at the acquisition date.

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The amount of financial assets (as defined) recognized as of the acquisition date.

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Amount recognized as of the acquisition date for the identifiable assets acquired in excess of (less than) the aggregate liabilities assumed.

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Amount of other liabilities due after one year or the normal operating cycle, if longer, assumed at the acquisition date.

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Amount of other assets expected to be realized or consumed after one year or the normal operating cycle, if longer, acquired at the acquisition date.

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The amount of property, plant, and equipment recognized as of the acquisition date.

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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