FS Bancorp (FSBW) 10-K 15 Mar 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Mar. 08, 2019	Jun. 30, 2018
Document And Entity Information
Entity Registrant Name	FS Bancorp, Inc.
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Amendment Flag	false
Entity Central Index Key	0001530249
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Voluntary Filers	No
Entity Public Float			$ 217,380,383
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Document Fiscal Year Focus	2018
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Document Fiscal Period Focus	FY
Entity Common Stock, Shares Outstanding		4,495,078

Consolidated Balance Sheet

Consolidated Balance Sheet - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
ASSETS
Cash and due from banks	$ 9,408	$ 3,043
Interest-bearing deposits at other financial institutions	23,371	15,872
Total cash and cash equivalents	32,779	18,915
Certificates of deposit at other financial institutions	22,074	18,108
Securities available-for-sale, at fair value	97,205	82,480
Loans held for sale, at fair value	51,195	53,463
Loans receivable, net	1,312,519	761,558
Accrued interest receivable	5,761	3,566
Premises and equipment, net	29,110	15,458
Federal Home Loan Bank (FHLB) stock, at cost	9,887	2,871
Other real estate owned (OREO)	689	0
Bank owned life insurance (BOLI), net	34,485	10,328
Servicing rights, held at the lower of cost or fair value	10,429	6,795
Goodwill	2,312	2,312
Core deposit intangible, net	6,217	1,317
Other assets	6,982	4,612
TOTAL ASSETS	1,621,644	981,783
LIABILITIES
Noninterest-bearing accounts	234,532	186,890
Interest-bearing accounts	1,039,687	642,952
Total deposits	1,274,219	829,842
Borrowings	137,149	7,529
Principal amount	10,000	10,000
Unamortized debt issuance costs	(135)	(155)
Total subordinated note less unamortized debt issuance costs	9,865	9,845
Deferred tax liability, net	361	607
Other liabilities	20,012	11,958
Total liabilities	1,441,606	859,781
COMMITMENTS AND CONTINGENCIES (NOTE 12)
STOCKHOLDERS' EQUITY
Preferred stock, $.01 par value; 5,000,000 shares authorized; none issued or outstanding	0	0
Common stock, $.01 par value; 45,000,000 shares authorized; 4,492,478 and 3,680,152 shares issued and outstanding at December 31, 2018 and December 31, 2017, respectively	45	37
Additional paid-in capital	91,466	55,135
Retained earnings	90,854	68,422
Accumulated other comprehensive loss, net of tax	(1,479)	(475)
Unearned shares - Employee Stock Ownership Plan ("ESOP")	(848)	(1,117)
Total stockholders' equity	180,038	122,002
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 1,621,644	$ 981,783

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Items Included in Consolidated Statement of Financial Condition [Abstract]
Preferred stock par value, in dollars per share	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock par value, in dollars per share	$ 0.01	$ 0.01
Common stock, shares authorized	45,000,000	45,000,000
Common stock, shares issued	4,492,478	3,680,152
Common stock, shares outstanding	4,492,478	3,680,152

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
INTEREST INCOME
Loans receivable, including fees	$ 58,616,000	$ 43,457,000
Interest and dividends on investment securities, cash and cash equivalents, and certificates of deposit at other financial institutions	3,710,000	2,724,000
Total interest and dividend income	62,326,000	46,181,000
INTEREST EXPENSE
Deposits	7,321,000	3,920,000
Borrowings	2,228,000	334,000
Subordinated note	679,000	679,000
Total interest expense	10,228,000	4,933,000
NET INTEREST INCOME	52,098,000	41,248,000
PROVISION FOR LOAN LOSSES	1,540,000	750,000
NET INTEREST INCOME AFTER PROVISION FOR LOAN LOSSES	50,558,000	40,498,000
NONINTEREST INCOME
Service charges and fee income	3,233,000	3,548,000
Bargain purchase gain	7,414,000	0
Gain on sale of loans	14,861,000	17,985,000
Loss on disposed fixed assets	(71,000)	0
Gain on sale of investment securities	171,000	380,000
Gain on sale of mortgage servicing rights (MSR)	0	1,062,000
Earnings on cash surrender value of BOLI	413,000	274,000
Other noninterest income	829,000	825,000
Total noninterest income	26,850,000	24,074,000
NONINTEREST EXPENSE
Salaries and benefits	28,538,000	26,595,000
Operations	6,709,000	6,205,000
Occupancy	3,042,000	2,672,000
Data processing	2,870,000	2,521,000
OREO expenses	2,000	0
Loan costs	2,801,000	2,652,000
Professional and board fees	1,872,000	1,697,000
Federal Deposit Insurance Corporation (FDIC) insurance	517,000	535,000
Marketing and advertising	747,000	716,000
Acquisition costs	1,389,000	0
Amortization of core deposit intangible	351,000	400,000
Total noninterest expense	48,838,000	43,993,000
INCOME BEFORE PROVISION FOR INCOME TAXES	28,570,000	20,579,000
PROVISION FOR INCOME TAXES	4,223,000	6,494,000
NET INCOME	$ 24,347,000	$ 14,085,000
Basic earnings per share (in dollars per share)	$ 6.58	$ 4.55
Diluted earnings per share (in dollars per share)	$ 6.29	$ 4.28

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net Income	$ 24,347	$ 14,085
Securities available-for-sale:
Unrealized holding (loss) gain during year	(1,108)	605
Income tax benefit (provision) related to unrealized holding (loss) gain	238	(213)
Reclassification adjustment for realized gain included in net income	(171)	(380)
Income tax provision related to reclassification for realized gain	37	133
Other comprehensive (loss) income, net of tax	(1,004)	145
COMPREHENSIVE INCOME	$ 23,343	$ 14,230

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income	Unearned ESOP Shares	Total
Beginning Balance at (in shares) at Dec. 31, 2016	3,059,503
Beginning balance at Dec. 31, 2016	$ 31	$ 27,334	$ 55,584	$ (536)	$ (1,380)	$ 81,033
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income			14,085			14,085
Dividends paid ($0.43 and $0.53 per share for 2017 and 2018, respectively)			(1,331)			(1,331)
Shares issued	$ 6	25,612				25,618
Shares issued (in shares)	587,234
Share-based compensation		634				634
Common stock repurchase		(275)				(275)
Common stock repurchased (in shares)	(6,198)
Stock options exercised		669				669
Stock options shares exercised (in shares)	39,613
Other comprehensive income (loss), net of tax				145		145
ESOP shares allocated		1,161			263	1,424
Income tax rate differential			84	(84)
Ending Balance at (in shares) at Dec. 31, 2017	3,680,152
Ending balance at Dec. 31, 2017	$ 37	55,135	68,422	(475)	(1,117)	122,002
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income			24,347			24,347
Dividends paid ($0.43 and $0.53 per share for 2017 and 2018, respectively)			(1,915)			(1,915)
Shares issued	$ 7	33,759				33,766
Shares issued (in shares)	725,518
Share-based compensation		767				767
Restricted stock awards (in shares)	25,000
Common stock repurchase		(251)				(251)
Common stock repurchased (in shares)	(4,325)
Stock options exercised	$ 1	1,116				$ 1,117
Stock options shares exercised (in shares)	66,133					66,133
Other comprehensive income (loss), net of tax				(1,004)		$ (1,004)
ESOP shares allocated		940			269	1,209
Ending Balance at (in shares) at Dec. 31, 2018	4,492,478
Ending balance at Dec. 31, 2018	$ 45	$ 91,466	$ 90,854	$ (1,479)	$ (848)	$ 180,038

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Statement of Stockholders' Equity [Abstract]
Dividends paid (in dollars per share)	$ 0.53	$ 0.43
Offering expenses		$ 326,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 24,347	$ 14,085
Adjustments to reconcile net income to net cash from operating activities
Provision for loan losses	1,540	750
Depreciation, amortization and accretion	5,263	3,938
Compensation expense related to stock options and restricted stock awards	767	634
ESOP compensation expense for allocated shares	1,209	1,424
Benefit for deferred income taxes	(768)	(718)
Increase in cash surrender value of BOLI	(413)	(274)
Bargain purchase gain	(7,414)	0
Gain on sale of loans held for sale	(14,654)	(17,487)
Gain on sale of portfolio loans	(207)	(498)
Gain on sale of investment securities	(171)	(380)
Gain on sale of MSR	0	(1,062)
Loss on disposed fixed assets	71	0
Origination of loans held for sale	(619,632)	(698,504)
Proceeds from sale of loans held for sale	631,309	711,766
Changes in operating assets and liabilities
Accrued interest receivable	(2,156)	(1,042)
Other assets	2,862	1,256
Other liabilities	(516)	1,196
Net cash from operating activities	21,437	15,084
Activity in securities available-for-sale:
Proceeds	24,312	39,103
Maturities, prepayments, sales, and calls	10,243	7,580
Purchases	(31,309)	(47,271)
Maturities of certificates of deposit at other financial institutions	992	1,240
Purchase of certificates of deposit at other financial institutions	(4,960)	(4,102)
Loan originations and principal collections, net	(190,125)	(155,793)
Purchase of portfolio loans	(24,007)	(38,950)
Proceeds from sale of portfolio loans	17,952	25,120
Purchase of premises and equipment, net	(3,796)	(1,016)
Purchase of BOLI	(3,000)	0
Net change in FHLB stock, net	(7,016)	(152)
Net cash acquired from Anchor Acquisition	23,753	0
Proceeds from sale of MSR	0	4,827
Net cash used by investing activities	(186,961)	(169,414)
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase in deposits	87,566	117,249
Proceeds from borrowings	917,239	495,274
Repayments of borrowings	(824,368)	(500,415)
Dividends paid	(1,915)	(1,331)
Proceeds from stock options exercised	1,117	669
Common stock repurchased	(251)	(275)
Proceeds from issuance of common stock	0	25,618
Net cash from financing activities	179,388	136,789
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	13,864	(17,541)
CASH AND CASH EQUIVALENTS, beginning of period	18,915	36,456
CASH AND CASH EQUIVALENTS, end of period	32,779	18,915
SUPPLEMENTARY DISCLOSURES OF CASH FLOW INFORMATION
Interest on deposits and borrowings	10,098	4,904
Income taxes	2,902	8,100
Assets acquired, excluding cash acquired	420,305	0
Liabilities assumed	402,878	0
SUPPLEMENTARY DISCLOSURES OF NONCASH OPERATING, INVESTING AND FINANCING ACTIVITIES
Change in unrealized (loss) gain on investment securities, net	(1,279)	225
Transfer portfolio loans to loans held for sale	0	1,886
Retention of gross mortgage servicing rights from loan sales	5,971	5,075
Additional paid-in-capital from common stock issued	$ 33,766	$ 25,618

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	NOTE 1 - BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Nature of Operations - FS Bancorp, Inc. (the “Company”) was incorporated in September 2011 as the proposed holding company for 1st Security Bank of Washington (the “Bank” or “1st Security Bank”) in connection with the Bank’s conversion from the mutual to stock form of ownership which was completed on July 9, 2012. The Bank is a community-based savings bank with 21 full-service bank branches, an administrative office that accepts deposits, and eight home loan production offices in suburban communities in the greater Puget Sound area which includes Snohomish, King, Pierce, Jefferson, Kitsap, Clallam, and the newly added Grays Harbor, Thurston, and Lewis counties, and one home loan production office in the market area of the Tri-Cities, Washington. The Bank provides loan and deposit services to customers who are predominantly small- and middle-market businesses and individuals. The Company and its subsidiary are subject to regulation by certain federal and state agencies and undergo periodic examination by these regulatory agencies. The Company expanded its footprint in 2018 through the recent merger and acquisition. On November 15, 2018, the Company completed its acquisition of Anchor Bancorp (“Anchor”), pursuant to the Agreement and Plan of Merger dated as of July 17, 2018 (the “Merger Agreement”) by and between FS Bancorp and Anchor. Under the terms of the Merger Agreement, Anchor merged with and into FS Bancorp (“Anchor Acquisition”), with FS Bancorp as the surviving corporation. Immediately after the Anchor Acquisition, FS Bancorp merged Anchor Bank, a wholly-owned subsidiary of Anchor, with and into 1st Security Bank of Washington, a wholly-owned subsidiary of FS Bancorp, with 1st Security Bank of Washington as the surviving bank. For additional information, see “Note 2 - Business Combination.” Pursuant to the Plan of Conversion (the “Plan”), the Company’s Board of Directors adopted an employee stock ownership plan ( “ESOP”) which purchased 8% of the common stock in the open market or 259,210 shares. As provided for in the Plan, the Bank also established a liquidation account in the amount of retained earnings at December 31, 2011. The liquidation account is maintained for the benefit of eligible savings account holders at June 30, 2007 and supplemental eligible account holders as of March 31, 2012, who maintain deposit accounts at the Bank after the conversion. The conversion was accounted for as a change in corporate form with the historic basis of the Company’s assets, liabilities, and equity unchanged as a result. Financial Statement Presentation - The consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) and with prevailing practices within the banking and securities industries. In preparing such financial statements, management is required to make certain estimates and judgments that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the balance sheet and the reported amounts of revenues and expenses for the reporting period. Actual results could differ significantly from those estimates. Material estimates that are particularly susceptible to significant change relate to the determination of the allowance for loan and lease losses, fair value of financial instruments, the valuation of servicing rights, and the deferred income taxes. Amounts presented in the consolidated financial statements and footnote tables are rounded and presented to the nearest thousands of dollars except per share amounts. If the amounts are above $1.0 million, they are rounded one decimal point, and if they are above $1.0 billion, they are rounded two decimal points. Certain prior year amounts have been reclassified to conform to the 2018 presentation with no change to consolidated net income or stockholders’ equity previously reported. Principles of Consolidation - The consolidated financial statements include the accounts of FS Bancorp, Inc. and its wholly owned subsidiary, 1st Security Bank of Washington. All material intercompany accounts have been eliminated in consolidation. Segment Reporting - The Company operates in two business segments through the Bank: commercial and consumer banking and home lending. The Company’s business segments are determined based on the products and services provided, as well as the nature of the related business activities, and they reflect the manner in which financial information is regularly reviewed for the purpose of allocating resources and evaluating performance of the Company’s businesses. The results for these business segments are based on management’s accounting process, which assigns income statement items and assets to each responsible operating segment. This process is dynamic and is based on management’s view of the Company’s operations. See “Note 19 - Business Segments.” Subsequent Events - The Company has evaluated events and transactions subsequent to December 31, 2018 for potential recognition or disclosure. Cash and Cash Equivalents - Cash and cash equivalents include cash and due from banks, and interest-bearing balances due from other banks and the Federal Reserve Bank of San Francisco (“FRB”) and have an original maturity of 90 days or less at the time of purchase. At times, cash balances may exceed Federal Deposit Insurance Corporation (“FDIC”) insured limits. At December 31, 2018 and 2017, the Company had $25,000 and $15,000, respectively, of cash and due from banks and interest-bearing deposits at other financial institutions in excess of FDIC insured limits. Because the Company places these deposits with major financial institutions and monitors the financial condition of these institutions, management believes the risk of loss to any deposits in excess of FDIC limits to be minimal. Securities Available-for-Sale - Securities available-for-sale consist of debt securities that the Company has the intent and ability to hold for an indefinite period, but not necessarily to maturity. Such securities may be sold to implement the Company’s asset/liability management strategies and in response to changes in interest rates and similar factors. Securities available-for-sale are reported at fair value. Realized gains and losses on securities available-for-sale, determined using the specific identification method, are included in results of operations. Amortization of premium and accretion of discounts are recognized in interest income over the period to maturity. Unrealized holding gains and losses, net of the related deferred tax effect, are reported as a net amount in a separate component of equity entitled accumulated other comprehensive income. Unrealized losses that are deemed to be other than temporary are reflected in results of operations. Any declines in the values of these securities that are considered to be other-than-temporary-impairment (“OTTI”) and credit-related are recognized in earnings. Noncredit-related OTTI on securities not expected to be sold is recognized in other comprehensive income. The review for OTTI is conducted on an ongoing basis and takes into account the severity and duration of the impairment, recent events specific to the issuer or industry, fair value in relationship to cost, extent and nature of change in fair value, creditworthiness of the issuer including external credit ratings and recent downgrades, trends and volatility of earnings, current analysts’ evaluations, and other key measures. In addition, the Company does not intend to sell the securities and it is more likely than not that we will not be required to sell the securities before recovery of their amortized cost basis. In doing this, we take into account our balance sheet management strategy and consideration of current and future market conditions. Dividends and interest income are recognized when earned. Federal Home Loan Bank Stock - The Bank’s investment in FHLB stock is carried at cost, which approximates fair value. As a member of the FHLB system, the Bank is required to maintain an investment in capital stock of the FHLB in an amount of $1 .7 million and 4.0% of advances from the FHLB. The Bank’s required minimum level of investment in FHLB stock is based on specific percentages of its outstanding mortgages, total assets, or FHLB advances. At December 31, 2018 and 2017, the Bank’s minimum level of investment requirement in FHLB stock was $9.9 million and $2.9 million, respectively. The Bank was in compliance with the FHLB minimum investment requirement at December 31, 2018 and 2017. Management evaluates FHLB stock for impairment as needed. Management’s determination of whether these investments are impaired is based on its assessment of the ultimate recoverability of cost rather than by recognizing temporary declines in value. The determination of whether a decline affects the ultimate recoverability of cost is influenced by criteria such as (1) the significance of any decline in net assets of the FHLB as compared with the capital stock amount for the FHLB and the length of time this situation has persisted; (2) commitments by the FHLB to make payments required by law or regulation and the level of such payments in relation to the operating performance of the FHLB; (3) the impact of legislative and regulatory changes on institutions and, accordingly, the customer base of the FHLB; and (4) the liquidity position of the FHLB. Based on its evaluation, management determined that there was no impairment of FHLB stock at December 31, 2018 and 2017, respectively. Loans Held for Sale - The Bank records all mortgage loans held-for-sale at fair value. Fair value is determined by outstanding commitments from investors or current investor yield requirements calculated on the aggregate loan basis. Origination fees and costs are recognized in earnings at the time of origination. Mortgage loans held for sale are sold with the mortgage service rights either released or retained by the Bank. Gains or losses on sales of mortgage loans are recognized based on the difference between the selling price and the carrying value of the related mortgage loans sold. All sales are made with limited recourse against the Company. Other Real Estate Owned - Other real estate owned (“OREO”) consists of properties or assets acquired through or in lieu of foreclosure, and are recorded initially at fair value less selling costs. Costs relating to development and improvement of the properties or assets are capitalized while costs relating to holding the properties or assets are expensed. Valuations are periodically performed by management, and a charge to earnings is recorded if the recorded value of a property exceeds its estimated net realizable value. Derivatives - Commitments to fund mortgage loans (interest rate locks) to be sold into the secondary market and forward commitments for the future delivery of these mortgage loans are accounted for as free-standing derivatives. The fair value of the interest rate lock is recorded at the time the commitment to fund the mortgage loan is executed and is adjusted for the expected exercise of the commitments to fund the loans, the Company enters into forward commitments for the future delivery of mortgage loans when interest rate locks are entered. Fair values of these mortgage derivatives are estimated based on changes in mortgage interest rates from the date the interest on the loan is locked. Changes in the fair values of these derivatives are reported in “Gain on sale of loans” on the Consolidated Statements of Income. Loans Receivable - Loans receivable, are stated at the amount of unpaid principal reduced by an allowance for loan losses and net deferred fees or costs. Interest on loans is calculated using the simple interest method based on the daily balance of the principal amount outstanding and is credited to income as earned. Loan fees, net of direct origination costs, are deferred and amortized over the life of the loan using the effective yield method. Interest on loans is accrued daily based on the principal amount outstanding. Generally, the accrual of interest on loans is discontinued when, in management’s opinion, the borrower may be unable to meet payments as they become due or when they are past due 90 days as to either principal or interest (based on contractual terms), unless they are well secured and in the process of collection. All interest accrued but not collected for loans that are placed on non-accrual status or charged off are reversed against interest income. Subsequent collections on a cash basis are applied proportionately to past due principal and interest, unless collectability of principal is in doubt, in which case all payments are applied to principal. Loans are returned to accrual status when the loan is performing according to its contractual terms for at least six months and the collectability of principal and interest is no longer doubtful. The Company charges fees for originating loans. These fees, net of certain loan origination costs, are deferred and amortized to income, based on the interest method, over the loan term. If the loan is repaid prior to maturity, the remaining unamortized net deferred loan origination fee is recognized in income at the time of repayment. Impaired Loans - A loan is considered impaired when it is probable the Company will be unable to collect all contractual principal and interest payments due in accordance with the original or modified terms of the loan agreement. Impaired loans are measured on a loan by loan basis based on the estimated fair value of the collateral less estimated cost to sell if the loan is considered collateral dependent. Impaired loans not considered to be collateral dependent are measured based on the present value of expected future cash flows. Impairment is measured for each loan in the portfolio except for the smaller groups of homogeneous consumer loans. The categories of non-accrual loans and impaired loans overlap, although they are not coextensive. The Company considers all circumstances regarding the loan and borrower on an individual basis when determining whether an impaired loan should be placed on non-accrual status, such as the financial strength of the borrower, the collateral value, reasons for delay, payment record, the amount of past due and the number of days past due. Loans that experience insignificant payment delays and payment shortfalls are generally not classified as impaired. Management determines the significance of payment delays and payment shortfalls on a case-by-case basis, taking into consideration all of the circumstances surrounding the loan and the borrower, including the length of the delay, the reasons for the delay, the borrower’s prior payment record, and the amount of shortfall in relation to the principal and interest owed. Allowance for Loan Losses - The allowance for loan losses is maintained at a level considered adequate to provide for probable losses on existing loans based on evaluating known and inherent risks in the loan portfolio. The allowance is reduced by loans charged off and increased by provisions charged to earnings and recoveries on loans previously charged-off. The allowance is based on management’s periodic, systematic evaluation of factors underlying the quality of the loan portfolio including changes in the size and composition of the loan portfolio, the estimated value of any underlying collateral, actual loan loss experience, current economic conditions, and detailed analysis of individual loans for which full collectability may not be assured. This evaluation is inherently subjective as it requires estimates that are susceptible to significant revision as more information becomes available. While management uses the best information available to make its estimates, future adjustments to the allowance may be necessary if there is a significant change in economic and other conditions. The appropriateness of the allowance for loan losses is estimated based on these factors and trends identified by management at the time the financial statements are prepared. When available information confirms that specific loans or portions thereof are uncollectible, these amounts are charged-off against the allowance for loan losses. The existence of some or all of the following criteria will generally confirm that a loss has been incurred: the loan is significantly delinquent and the borrower has not evidenced the ability or intent to bring the loan current; the Company has no recourse to the borrower, or if it does, the borrower has insufficient assets to pay the debt; the estimated fair value of the loan collateral is significantly below the current loan balance, and there is little or no near-term prospect for improvement. A provision of loan losses is charged against income and added to the allowance for loan losses based on regular assessment of the loan portfolio. The allowance for loan losses is allocated to certain loan categories based on the relative risk characteristics, asset classifications, and actual loss experience within the loan portfolio. Although management has allocated the allowance for loan losses to various loan portfolio segments, the allowance is general in nature and is available for the loan portfolio in its entirety. The ultimate recovery of all loans is susceptible to future market factors beyond the Company’s control. These factors may result in losses or recoveries differing significantly from those provided for in the financial statements. In addition, regulatory agencies, as an integral part of their examination process, periodically review the Company’s allowance for loan losses, and may require the Company to make additions to the allowance based on their judgment about information available to them at the time of their examinations. Reserve for Unfunded Loan Commitments - The reserve for unfunded loan commitments is maintained at a level believed by management to be sufficient to absorb estimated probable losses related to these unfunded credit facilities. The determination of the adequacy of the reserve is based on periodic evaluations of the unfunded credit facilities including an assessment of the probability of commitment usage, credit risk factors for loans outstanding to these same customers, and the terms and expiration dates of the unfunded credit facilities. The reserve for unfunded loan commitments is included in other liabilities on the consolidated balance sheet, with changes to the balance charged against noninterest expense. Premises and Equipment, Net - Land is carried at cost. Premises and equipment are stated at cost less accumulated depreciation and amortization. Depreciation is computed using the straight-line method over the estimated useful lives of the assets. The estimated useful lives used to compute depreciation include building and building improvements from 25 to 40 years and furniture, fixtures, and equipment from 3 to 10 years. Leasehold and tenant improvements are amortized using the straight-line method over the lesser of useful life or the life of the related lease. Gains or losses on dispositions are reflected in results of operations. Management reviews buildings, improvements and equipment for impairment on an annual basis or whenever events or changes in the circumstances indicate that the undiscounted cash flows for the property are less than its carrying value. If identified, an impairment loss is recognized through a charge to earnings based on the fair value of the property. Transfers of Financial Assets - Transfers of an entire financial asset, a group of entire financial assets, or participating interest in an entire financial asset are accounted for as sales when control over the assets has been surrendered. Control over transferred assets is deemed to be surrendered when (1) the assets have been isolated from the Company, (2) the transferee obtains the right (free of conditions that constrain it from taking advantage of that right) to pledge or exchange the transferred assets, and (3) the Company does not maintain effective control over the transferred assets through an agreement to repurchase them before their maturity. Servicing Rights - Servicing assets are recognized as separate assets when rights are acquired through purchase or through sale of financial assets. Generally, purchased servicing rights are capitalized at the cost to acquire the rights. For sales of mortgage, commercial and consumer loans, a portion of the cost of originating the loan is allocated to the servicing right based on relative fair value. Fair value is based on market prices for comparable mortgage, commercial, or consumer servicing contracts, when available, or alternatively, is based on a valuation model that calculates the present value of estimated future net servicing income. The valuation model incorporates assumptions that market participants would use in estimating future net servicing income, such as the cost to service, the discount rate, the custodial earnings rate, an inflation rate, ancillary income, prepayment speeds, and default rates and losses. Servicing assets are evaluated quarterly for impairment based upon the fair value of the rights as compared to amortized cost. Impairment is determined by stratifying rights into tranches based on predominant characteristics, such as interest rate, loan type, and investor type. Impairment is recognized through a valuation allowance for an individual tranche, to the extent that fair value is less than the capitalized amount for the tranches. If the Company later determines that all or a portion of the impairment no longer exists for a particular tranche, a reduction of the allowance may be recorded as an increase to income. Capitalized servicing rights are stated separately on the Consolidated Balance Sheets and are amortized into noninterest income in proportion to, and over the period of, the estimated future net servicing income of the underlying financial assets. Income Taxes - The Company files a consolidated federal income tax return. Deferred federal income taxes result from temporary differences between the tax basis of assets and liabilities, and their reported amounts in the financial statements. These will result in differences between income for tax purposes and income for financial reporting purposes in future years. As changes in tax laws or rates are enacted, deferred tax assets and liabilities are adjusted through the provision for income taxes. Valuation allowances are established to reduce the net recorded amount of deferred tax assets if it is determined to be more likely than not, that all or some portion of the potential deferred tax asset will not be realized. The Company follows the authoritative guidance issued related to accounting for uncertainty in income taxes. The guidance prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. It is the Company’s policy to record any penalties or interest arising from federal or state taxes as a component of income tax expense. Employee Stock Ownership Plan - Compensation expense recognized for the Company’s ESOP equals the fair value of shares that have been allocated or committed to be released for allocation to participants. Any difference between the fair value of the shares at the time and the ESOP’s original acquisition cost is charged or credited to stockholders’ equity (additional paid-in capital). The cost of ESOP shares that have not yet been allocated or committed to be released is deducted from stockholders’ equity. Earnings Per Share (“EPS”) - Basic EPS are computed by dividing income available to common stockholders by the weighted average number of common shares outstanding for the period. Diluted earnings per share reflect the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock or resulted in the issuance of common stock that then shared in the earnings of the entity. For purposes of computing basic and dilutive EPS, ESOP shares that have been committed to be released are outstanding and ESOP shares that have not been committed to be released shall not be considered outstanding. Comprehensive Income (Loss) - Comprehensive income (loss) is comprised of net income and other comprehensive income (loss). Other comprehensive income (loss) includes items recorded directly to equity, such as unrealized holding gains and losses on securities available-for-sale. Financial Instruments - In the ordinary course of business, the Company has entered into agreements for off-balance-sheet financial instruments consisting of commitments to extend credit and stand-by letters of credit. Such financial instruments are recorded in the financial statements when they are funded or related fees are incurred or received. Restricted Assets – Regulations of the Board of Governors of the Federal Reserve System (“Federal Reserve”) require that the Bank maintain reserves in the form of cash on hand and deposit balances with the FRB, based on a percentage of deposits. The amounts of such balances for the years ended December 31, 2018 and 2017 were $17.4 million and $18.2 million, respectively, included in interest-bearing deposits at other financial institutions on the Consolidated Balance Sheets. Marketing and Advertising Costs - The Company records marketing and advertising costs as expenses as they are incurred. Total marketing and advertising expense was $747,000 and $716,000 for the years ended December 31, 2018 and 2017, respectively. Stock-Based Compensation - Compensation cost is recognized for stock options and restricted stock awards, based on the fair value of these awards at the grant date. A Black-Scholes model is utilized to estimate the fair value of stock options, while the market price of the Company’s common stock at the grant date is used for restricted stock awards. Compensation cost is recognized over the required service period, generally defined as the vesting period. For awards with graded vesting, compensation cost is recognized on a straight-line basis over the requisite service period for the entire award. Goodwill - Goodwill is recorded upon completion of a business combination as the difference between the purchase price and the fair value of net identifiable assets acquired. Goodwill was not recorded until the first quarter of 2016 in recognition of the four retail branches purchased from Bank of America on January 22, 2016. Subsequent to initial recognition, the Company tests goodwill for impairment during the fourth quarter of each fiscal year, or more often if events or circumstances, such as adverse changes in the business climate indicate there may be impairment. There was no goodwill impairment at December 31, 2018 or 2017. Application of New Accounting Guidance On January 1, 2018, the Company adopted Financial Accounting Standards Board (“FASB’) Accounting Standards Update (“ASU”) No. 2014‑09, Revenue from Contracts with Customers and all subsequent amendments to the ASU (collectively “ASC 606”) , which created Topic 606 and superseded Topic 605, Revenue Recognition. In August 2015, FASB issued ASU No. 2015‑14, Revenue from Contracts with Customers (Topic 606) , which postponed the effective date of ASU No. 2014‑09. The core principle of Topic 606 is that an entity recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In general, the new guidance requires companies to use more judgment and make more estimates than under past guidance, including identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. For financial reporting purposes, the Company utilized the modified retrospective approach, meaning the ASU is applied only to the most current period presented in the financial statements with the cumulative effect of initially applying the standard recognized at the date of initial application. As a bank holding company, key revenue sources, such as interest income on loans, investment securities and deposits, as well as other sources of income including loan fees, security sales, and derivatives have been identified as out of the scope of this new guidance. Management conducted an assessment of the revenue streams that were affected by the new guidance and identified those considered material and in scope to ensure compliance with the new guidance concluding those related to credit and debit card fees, and service charges and fees on deposit accounts. No additional changes to processes or procedures were identified for the recognition of revenues in scope. The adoption of this ASU did not have a material impact on the Company’s consolidated financial statements. However, additional disclosures required by the ASU have been included in “Note 15 - Revenue from Contracts with Customers” to the Company’s consolidated financial statements. On January 1, 2018, the FASB issued ASU No. 2016‑01, Financial Instruments - Overall (Subtopic 825‑10): Recognition and Measurement of Financial Assets and Financial Liabilities. The new guidance improves the recognition and measurement of financial instruments. This ASU requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes and requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset (i.e., securities or loans and receivables) on the balance sheet or the accompanying notes to the financial statements. Exit price is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. This ASU also eliminates the requirement to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet. The adoption of ASU No. 2016-01 did not have a material impact on the Company’s consolidated financial statements. The disclosures to the Company’s consolidated financial statements have been updated appropriately using the exit price notion in “Note 15 - Fair Value of Financial Instruments.” RECENT ACCOUNTING PRONOUNCEMENTS In February 2016, the FASB issued ASU No. 2016‑02, Leases (Topic 842) . ASU No. 2016‑02 requires lessees to recognize on the balance sheet the assets and liabilities arising from operating leases. A lessee should recognize a liability to make lease payments and a right-of-use asset representing its right to use the underlying asset for the lease term. A lessee should include payments to be made in an optional period only if the lessee is reasonably certain to exercise an option to extend the lease or not to exercise an option to terminate the lease. For a finance lease, interest payments should be recognized separately from amortization of the right-of-use asset in the statement of comprehensive income. For operating leases, the lease cost should be allocated over the lease term on a generally straight-line basis. The amendments in ASU 2016‑02 are effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early application of the amendments in the ASU is permitted. In July 2018, the FASB issued ASU No, 2018-10, Codification Improvements to Topic 842, Leases and ASU No. 2018-11, Leases (Topic 842): Targeted Improvements. These ASUs contain clarifications to ASU 2016-02, including providing a new transition method in addition to the existing transition method contained in ASU No. 2016-02 to allow entities to initially apply the new standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. These amendments have the same effective date as ASU 2016-02. The effect of the adoption of these ASUs will depend on leases at time of adoption. The Company expects to adopt the new standard on January 1, 2019 and use the adoption date as the date of in

Business Combination

Business Combination	12 Months Ended
	Dec. 31, 2018
Business Combination [Abstract]
Business Combination	NOTE 2 - BUSINESS COMBINATION On November 15, 2018, the Company completed its acquisition of Anchor Bancorp, pursuant to the Agreement and Plan of Merger dated as of July 17, 2018 by and between FS Bancorp and Anchor. Under the terms of the Merger Agreement, Anchor merged with and into FS Bancorp, with FS Bancorp as the surviving corporation. Immediately after the Anchor Acquisition, FS Bancorp merged Anchor Bank, a wholly-owned subsidiary of Anchor, with and into 1st Security Bank of Washington, a wholly-owned subsidiary of FS Bancorp, with 1st Security Bank of Washington as the surviving bank. Anchor’s principal business activities prior to the acquisition were attracting retail deposits from the general public and utilizing those deposits to originate loans including one-to-four-family residences, commercial real estate, and multi-family residences located in Western Washington. Anchor’s principal lending activity had consisted of the origination of loans secured by first mortgages on owner-occupied, one-to-four-family residences and loans for the construction of one-to-four-family residences, as well as consumer loans, with an emphasis on home equity loans and lines of credit. The primary objective for the acquisition was to significantly expand FS Bancorp’s presence throughout Western Washington, increase nonmaturity deposits, and offer additional banking and lending products to former Anchor customers as well as new customers. The Anchor Acquisition was accounted for under the acquisition method of accounting and accordingly, the assets and liabilities were recorded at their fair values on November 15, 2018, the date of acquisition. Determining the fair value of assets and liabilities is a complicated process involving significant judgment regarding methods and assumptions used to calculate estimated fair values. Fair values are preliminary and subject to refinement for up to one year after the closing date of the acquisition as information relative to closing date fair values become available. The following table summarizes the estimated fair values of assets acquired and liabilities assumed at the date of acquisition: Acquired Book Fair Value Amount November 15, 2018 Value Adjustments Recorded Assets Cash and cash equivalents $ 54,558 $ — $ 54,558 Securities available-for-sale 19,609 (54) 19,555 Loans receivable, net 361,596 (5,321) (1) 356,275 Premises and equipment, net 8,411 3,354 (2) 11,765 Other real estate owned 689 — 689 Deferred tax asset 4,097 (3,358) 739 Mortgage servicing rights 218 564 782 Core deposit intangible (“CDI”) — 5,251 (3) 5,251 Other assets 25,231 18 25,249 Total assets acquired $ 474,409 $ 454 $ 474,863 Liabilities Deposits $ 357,863 $ (1,052) (4) $ 356,811 Borrowings 37,000 (282) 36,718 Other liabilities 9,286 63 9,349 Total liabilities assumed $ 404,149 $ (1,271) $ 402,878 Explanation of Fair Value Adjustments (1) The fair value discount for acquired loans from Anchor was $5.3 million and was determined by separate adjustments to reflect a credit risk and marketability component and a yield component reflecting the differential between portfolio and market yields. The discount on acquired loans will be accreted back into interest income over an estimated average life of 60 months. (2) The fair value adjustment represents the difference between the fair value of the premises and the book value of the those assets acquired. The Company utilized third-party valuations including appraisals, comparative market analysis, and tax-assessed values to assist in the determination of the fair value. (3) The fair value adjustment of $5.3 million represents the value of the core deposit base assumed on a study performed by an independent consulting firm. This amount was recorded by the Company as an identifiable intangible asset and will be amortized as an expense on a straight-line basis over an estimated 10 year life of the core deposit base and will be reviewed for impairment annually. See “Note 21- Goodwill and Other Intangible Assets.” (4) The fair value of transaction and savings accounts was determined to be equal to their carrying values. The fair value of time deposits was calculated using a discounted cash flow analysis that calculated the present value of the projected cash flows from the portfolio versus the present value of a similar portfolio with a similar maturity profile at current market rates. As of the acquisition date, the portfolio of time deposits was valued at a pre-tax discount of $1.1 million, or 0.65% of core deposits. This adjustment represents a difference in interest rates from the time deposits acquired and the estimated wholesale funding rates used in the application of fair value accounting. The discounted amount will be accreted into expense as an increase in interest expense over the maturity profile of the acquired time deposits. The following table summarizes the consideration paid, the aggregate amount recognized for each major class of assets acquired and liabilities assumed by 1st Security Bank in the Anchor Acquisition: At November 15, 2018 Purchase price of Anchor Fair value of FS Bancorp common stock at $46.54 (1) per share for 725,518 shares $ Cash paid Total purchase price Fair value of assets acquired: Cash and cash equivalents $ 54,558 Securities available-for-sale 19,555 Loans receivable, net 356,275 Premises and equipment 11,765 OREO 689 Deferred tax asset 739 Mortgage servicing rights 782 Intangible assets - CDI 5,251 Other assets 25,249 Total assets and identifiable intangible assets acquired $ 474,863 Fair value of liabilities assumed: Deposits $ 356,811 Borrowings 36,718 Other liabilities 9,349 Total liabilities assumed $ 402,878 Fair value of net assets and identifiable intangible assets acquired Bargain purchase gain $ _________________________ (1) Stock price is as of the closing date. The application of the acquisition method of accounting resulted in a bargain purchase gain of $7.4 million which was reported as a component of noninterest income on our Consolidated Statements of Income. The bargain purchase gain was primarily due to the decline in the value of the stock portion of the merger consideration between signing and closing the Anchor Acquisition which resulted in the purchase price for Anchor being less than the fair market value of the net assets acquired. In the merger, each Anchor shareholder received 0.291 of a share of FS Bancorp common stock for each share of Anchor common stock along with $12.40 in cash. The Company determined that the disclosure requirements related to the amounts of revenues and earnings of Anchor included in the consolidated statements of operations since the November 15, 2018 acquisition date is impracticable. The financial activity and operating results of Anchor were commingled with the Company’s financial activity and operating results as of the acquisition date.

Securities Available-for-sale

Securities Available-for-sale	12 Months Ended
	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]	NOTE 3 - SECURITIES AVAILABLE-FOR-SALE The following tables present the amortized costs, unrealized gains, unrealized losses, and estimated fair values of securities available-for-sale at December 31, 2018 and 2017: December 31, 2018 Estimated Amortized Unrealized Unrealized Fair Cost Gains Losses Values SECURITIES AVAILABLE-FOR-SALE U.S. agency securities $ 16,052 $ 32 $ (197) $ 15,887 Corporate securities 7,074 — (209) 6,865 Municipal bonds 14,446 23 (275) 14,194 Mortgage-backed securities 45,827 83 (1,074) 44,836 U.S. Small Business Administration securities 15,690 — (267) 15,423 Total securities available-for-sale $ 99,089 $ 138 $ (2,022) $ 97,205 December 31, 2017 Estimated Amortized Unrealized Unrealized Fair Cost Gains Losses Values SECURITIES AVAILABLE-FOR-SALE U.S. agency securities $ 9,077 $ 49 $ (11) $ 9,115 Corporate securities 7,113 9 (96) 7,026 Municipal bonds 12,720 148 (82) 12,786 Mortgage-backed securities 40,161 63 (490) 39,734 U.S. Small Business Administration securities 14,014 — (195) 13,819 Total securities available-for-sale $ 83,085 $ 269 $ (874) $ 82,480 At Decemb er 31, 2018, t he Bank pledged 11 securities held at the FHLB with a carrying value of $13.7 million to secure Washington State public deposits of $19.9 million with an $8.4 million collateral requirement by the Washington Public Deposit Protection Commission. At Decemb er 31, 2017, t he Bank pledged nine securities held at the FHLB of Des Moines with a carrying value of $10.7 million to secure Washington State public deposits of $7.6 million with a $3.2 million minimum collateral requirement by the Washington Public Deposit Protection Commission. Investment securities that were in an unrealized loss position at December 31, 2018 and 2017 are presented in the following tables, based on the length of time individual securities have been in an unrealized loss position. Management believes that these securities are only temporarily impaired due to changes in market interest rates or the widening of market spreads subsequent to the initial purchase of the securities, and not due to concerns regarding the underlying credit of the issuers or the underlying collateral. December 31, 2018 Less than 12 Months 12 Months or Longer Total Fair Unrealized Fair Unrealized Fair Unrealized Value Losses Value Losses Value Losses SECURITIES AVAILABLE-FOR-SALE U.S. agency securities $ 6,018 $ (25) $ 4,822 $ (172) $ 10,840 $ (197) Corporate securities 975 (25) 5,890 (184) 6,865 (209) Municipal bonds 2,098 (22) 8,787 (253) 10,885 (275) Mortgage-backed securities 6,266 (40) 32,537 (1,034) 38,803 (1,074) U.S. Small Business Administration securities 1,958 (11) 13,465 (256) 15,423 (267) Total $ 17,315 $ (123) $ 65,501 $ (1,899) $ 82,816 $ (2,022) December 31, 2017 Less than 12 Months 12 Months or Longer Total Fair Unrealized Fair Unrealized Fair Unrealized Value Losses Value Losses Value Losses SECURITIES AVAILABLE-FOR-SALE U.S. agency securities $ 2,987 $ (11) $ — $ — $ 2,987 $ (11) Corporate securities 4,102 (15) 1,915 (81) 6,017 (96) Municipal bonds 5,982 (82) — — 5,982 (82) Mortgage-backed securities 7,262 (61) 20,635 (429) 27,897 (490) U.S. Small Business Administration securities 11,876 (162) 1,943 (33) 13,819 (195) Total $ 32,209 $ (331) $ 24,493 $ (543) $ 56,702 $ (874) There were 14 investments with unrealized losses of less than one year and 48 investments with unrealized losses of more than one year at December 31, 2018. There were 21 investments with unrealized losses of less than one year and 17 investments with unrealized losses of more than one year at December 31, 2017. The unrealized losses associated with these investments are believed to be caused by changing market conditions that are considered to be temporary and the Company does not intend to sell these securities, and it is not likely to be required to sell these securities prior to maturity. Based on the Company’s evaluation of these securities, no OTTI impairment was recorded for the years ended December 31, 2018 and 2017. The contractual maturities of securities available-for-sale at December 31, 2018 and 2017 are listed below. Expected maturities of mortgage-backed securities may differ from contractual maturities because borrowers may have the right to call or prepay the obligations; therefore, these securities are classified separately with no specific maturity date. December 31, 2018 December 31, 2017 Amortized Fair Amortized Fair Cost Value Cost Value U.S. agency securities Due after one year through five years $ 1,043 $ 1,040 $ — $ — Due after five years through ten years 10,011 9,941 4,079 4,124 Due after ten years 4,998 4,906 4,998 4,991 Subtotal 16,052 15,887 9,077 9,115 Corporate securities Due after one year through five years 6,077 5,947 5,117 5,111 Due after five years through ten years 997 918 1,996 1,915 Subtotal 7,074 6,865 7,113 7,026 Municipal bonds Due after one year through five years 2,659 2,570 2,001 2,026 Due after five years through ten years 2,610 2,592 4,111 4,206 Due after ten years 9,177 9,032 6,608 6,554 Subtotal 14,446 14,194 12,720 12,786 Mortgage-backed securities Federal National Mortgage Association (“FNMA”) 30,554 30,026 23,310 23,091 Federal Home Loan Mortgage Corporation (“FHLMC”) 10,301 9,961 10,818 10,629 Government National Mortgage Association (“GNMA”) 4,972 4,849 6,033 6,014 Subtotal 45,827 44,836 40,161 39,734 U.S. Small Business Administration securities Due after five years through ten years 13,828 13,581 12,065 11,896 Due after ten years 1,862 1,842 1,949 1,923 Subtotal 15,690 15,423 14,014 13,819 Total $ 99,089 $ 97,205 $ 83,085 $ 82,480 The proceeds and resulting gains and losses, computed using specific identification from sales of securities available-for-sale for the years ended December 31, 2018 and 2017 were as follows: December 31, 2018 Proceeds Gross Gains Gross Losses Securities available-for-sale $ 24,312 $ 185 $ (14) December 31, 2017 Proceeds Gross Gains Gross Losses Securities available-for-sale $ 39,103 $ 413 $ (33)

Loans Receivable and Allowance

Loans Receivable and Allowance For Loan Losses	12 Months Ended
	Dec. 31, 2018
Receivables [Abstract]
Loans Receivable and Allowance For Loan Losses	NOTE 4 - LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES The composition of the loan portfolio was as follows at December 31: December 31, December 31, 2018 2017 REAL ESTATE LOANS Commercial $ 204,699 $ 63,611 Construction and development 247,306 143,068 Home equity 40,258 25,289 One-to-four-family (excludes loans held for sale) 249,397 163,655 Multi-family 104,663 44,451 Total real estate loans 846,323 440,074 CONSUMER LOANS Indirect home improvement 167,793 130,176 Solar 44,433 41,049 Marine 57,822 35,397 Other consumer 5,425 2,046 Total consumer loans 275,473 208,668 COMMERCIAL BUSINESS LOANS Commercial and industrial 138,686 83,306 Warehouse lending 65,756 41,397 Total commercial business loans 204,442 124,703 Total loans receivable, gross 1,326,238 773,445 Allowance for loan losses (12,349) (10,756) Deferred costs and fees, net (2,907) (2,708) Premiums on purchased loans 1,537 1,577 Total loans receivable, net $ 1,312,519 $ 761,558 The loans listed above for December 31, 2018 include $328.2 million of loans acquired at fair value on November 15, 2018 as part of the Anchor Acquisition. The Company has defined its loan portfolio into three segments that reflect the structure of the lending function, the Company’s strategic plan and the manner in which management monitors performance and credit quality. The three loan portfolio segments are: (a) Real Estate Loans, (b) Consumer Loans and (c) Commercial Business Loans. Each of these segments is disaggregated into classes based on the risk characteristics of the borrower and/or the collateral type securing the loan. The following is a summary of each of the Company’s loan portfolio segments and classes: Real Estate Loans Commercial Lending. Loans originated by the Company primarily secured by income producing properties, including retail centers, warehouses, and office buildings located in our market areas. Construction and Development Lending . Loans originated by the Company for the construction of, and secured by, commercial real estate, one-to-four-family, and multi-family residences and tracts of land for development that are not pre-sold. A small portion of the one-to-four-family construction portfolio is custom construction loans to the intended occupant of the residence. Home Equity Lending . Loans originated by the Company secured by second mortgages on one-to-four-family residences, including home equity lines of credit in our market areas. One-to-Four-Family Real Estate Lending . One-to-four-family residential loans include owner occupied properties (including second homes), and non-owner occupied properties with four or less units. These loans originated by the Company are secured by first mortgages on one-to-four-family residences in our market areas that the Company intends to hold (excludes loans held for sale). Multi-family Lending . Apartment term lending (5 or more units) to current banking customers and community reinvestment loans for low to moderate income individuals in the Company’s footprint. Consumer Loans Indirect Home Improvement . Fixture secured loans for home improvement are originated by the Company through its network of home improvement contractors and dealers and are secured by the personal property installed in, on, or at the borrower’s real property, and may be perfected with a UCC‑2 financing statement filed in the county of the borrower’s residence. These indirect home improvement loans include replacement windows, siding, roofing, and other home fixture installations. Solar. Fixture secured loans for solar related home improvement projects are originated by the Company through its network of contractors and dealers and are secured by the personal property installed in, on, or at the borrower’s real property, and which may be perfected with a UCC‑2 financing statement filed in the county of the borrower’s residence. Marine. Loans originated by the Company, secured by boats, to borrowers primarily located in the states the Company originates consumer loans. Other Consumer. Loans originated by the Company to consumers in our retail branch footprint, including automobiles, recreational vehicles, direct home improvement loans, loans on deposits, and other consumer loans, primarily consisting of personal lines of credit and credit cards. Commercial Business Loans Commercial and Industrial Lending (“C&I”) . Loans originated by the Company to local small- and mid-sized businesses in our Puget Sound market area are secured primarily by accounts receivable, inventory, or personal property, plant and equipment. Some of the C&I loans purchased by the Company are outside of the Greater Puget Sound market area. C&I loans are made on the basis of the borrower’s ability to make repayment from the cash flow of the borrower’s business. Warehouse Lending . Loans originated to non-depository financial institutions and secured by notes originated by the non-depository financial institution. The Company has two distinct warehouse lending divisions: commercial warehouse re-lending secured by notes on construction loans and mortgage warehouse re-lending secured by notes on one-to-four-family loans. The Company’s commercial construction warehouse lines are secured by notes on construction loans and typically guaranteed by principles with experience in construction lending. Mortgage warehouse lending loans are funded through third-party residential mortgage bankers. Under this program, the Company provides short-term funding to the mortgage banking companies for the purpose of originating residential mortgage loans for sale into the secondary market. The following tables detail activities in the allowance for loan losses by loan categories for the years shown: At or For the Year Ended December 31, 2018 Commercial Real Estate Consumer Business Unallocated Total ALLOWANCE FOR LOAN LOSSES Beginning balance $ 4,770 $ 2,814 $ 2,014 $ 1,158 $ 10,756 Provision for loan losses 953 526 1,173 (1,112) 1,540 Charge-offs (4) (936) — — (940) Recoveries 42 947 4 — 993 Net recoveries 38 11 4 — 53 Ending balance $ 5,761 $ 3,351 $ 3,191 $ 46 $ 12,349 Period end amount allocated to: Loans individually evaluated for impairment $ 125 $ 150 $ 700 $ — $ 975 Loans collectively evaluated for impairment 5,636 3,201 2,491 46 11,374 Ending balance $ 5,761 $ 3,351 $ 3,191 $ 46 $ 12,349 LOANS RECEIVABLE Loans individually evaluated for impairment $ 834 $ 428 $ 1,685 $ — $ 2,947 Loans collectively evaluated for impairment 845,489 275,045 202,757 — 1,323,291 Ending balance $ 846,323 $ 275,473 $ 204,442 $ — $ 1,326,238 At or For the Year Ended December 31, 2017 Commercial Real Estate Consumer Business Unallocated Total ALLOWANCE FOR LOAN LOSSES Beginning balance $ 3,547 $ 2,082 $ 2,675 $ 1,907 $ 10,211 Provision for loan losses 1,253 884 (638) (749) 750 Charge-offs (65) (832) (33) — (930) Recoveries 35 680 10 — 725 Net charge-offs (30) (152) (23) — (205) Ending balance $ 4,770 $ 2,814 $ 2,014 $ 1,158 $ 10,756 Period end amount allocated to: Loans individually evaluated for impairment $ 21 $ 68 $ — $ — $ 89 Loans collectively evaluated for impairment 4,749 2,746 2,014 1,158 10,667 Ending balance $ 4,770 $ 2,814 $ 2,014 $ 1,158 $ 10,756 LOANS RECEIVABLE Loans individually evaluated for impairment $ 348 $ 195 $ 551 $ — $ 1,094 Loans collectively evaluated for impairment 439,726 208,473 124,152 — 772,351 Ending balance $ 440,074 $ 208,668 $ 124,703 $ — $ 773,445 Non-Accrual and Past Due Loans . Loans are considered past due if the required principal and interest payments have not been received as of the date such payments were due. Loans are automatically placed on non-accrual once the loan is 90 days past due or sooner if, in management’s opinion, the borrower may be unable to meet payment obligations as they become due, or as required by regulatory authorities. The following tables provide information pertaining to the aging analysis of contractually past due loans and non-accrual loans for the years ended December 31, 2018 and 2017: December 31, 2018 30-59 60-89 Days Days 90 Days Total Total Past Past or More Past Loans Non- Due Due Past Due Due Current Receivable Accrual REAL ESTATE LOANS Commercial $ — $ — $ — $ — $ 204,699 $ 204,699 $ — Construction and development — — — — 247,306 247,306 — Home equity 158 40 229 427 39,831 40,258 229 One-to-four-family 1,274 164 1,358 2,796 246,601 249,397 1,552 Multi-family — — — — 104,663 104,663 — Total real estate loans 1,432 204 1,587 3,223 843,100 846,323 1,781 CONSUMER LOANS Indirect home improvement 438 196 113 747 167,046 167,793 367 Solar 62 43 41 146 44,287 44,433 41 Marine 50 — — 50 57,772 57,822 18 Other consumer 69 24 11 104 5,321 5,425 2 Total consumer loans 619 263 165 1,047 274,426 275,473 428 COMMERCIAL BUSINESS LOANS Commercial and industrial — 431 — 431 138,255 138,686 1,685 Warehouse lending — — — — 65,756 65,756 — Total commercial business loans — 431 — 431 204,011 204,442 1,685 Total loans $ 2,051 $ 898 $ 1,752 $ 4,701 $ 1,321,537 $ 1,326,238 $ 3,894 December 31, 2017 30-59 60-89 Days Days 90 Days Total Total Past Past or More Past Loans Non- Due Due Past Due Due Current Receivable Accrual REAL ESTATE LOANS Commercial $ — $ — $ — $ — $ 63,611 $ 63,611 $ — Construction and development — — — — 143,068 143,068 — Home equity 122 — 136 258 25,031 25,289 151 One-to-four-family 142 — — 142 163,513 163,655 142 Multi-family — — — — 44,451 44,451 — Total real estate loans 264 — 136 400 439,674 440,074 293 CONSUMER LOANS Indirect home improvement 255 215 99 569 129,607 130,176 195 Solar 49 19 — 68 40,981 41,049 — Marine — — — — 35,397 35,397 — Other consumer — — — — 2,046 2,046 — Total consumer loans 304 234 99 637 208,031 208,668 195 COMMERCIAL BUSINESS LOANS Commercial and industrial — 551 — 551 82,755 83,306 551 Warehouse lending — — — — 41,397 41,397 — Total commercial business loans — 551 — 551 124,152 124,703 551 Total loans $ 568 $ 785 $ 235 $ 1,588 $ 771,857 $ 773,445 $ 1,039 There were two other consumer loans totaling $11,000 that were 90 days or more past due and still accruing interest at December 31, 2018 and no loa ns 90 days or more past due and accruing interest at December 31, 2017. The following tables provide additional information about our impaired loans that have been segregated to reflect loans for which an allowance for credit losses has been provided and loans for which no allowance was provided for the years ended December 31, 2018 and 2017: December 31, 2018 Unpaid Principal Recorded Related Balance Impairment Investment Allowance WITH NO RELATED ALLOWANCE RECORDED Home equity $ 229 $ — $ 229 $ — WITH RELATED ALLOWANCE RECORDED One-to-four-family 1,552 — 1,552 125 Consumer loans 428 — 428 150 Commercial business loans 1,685 — 1,685 700 3,665 — 3,665 975 Total $ 3,894 $ — $ 3,894 $ 975 December 31, 2017 Unpaid Principal Recorded Related Balance Impairment Investment Allowance WITH NO RELATED ALLOWANCE RECORDED Home equity $ 151 $ — $ 151 $ — One-to-four-family 67 (12) 55 — Total real estate loans 218 (12) 206 — Commercial business loans 551 — 551 — 769 (12) 757 — WITH RELATED ALLOWANCE RECORDED One-to-four-family 142 — 142 21 Consumer loans 195 — 195 68 337 — 337 89 Total $ 1,106 $ (12) $ 1,094 $ 89 The following table presents the average recorded investment in loans individually evaluated for impairment and the interest income recognized and received for the years ended December 31, 2018 and 2017: At or For the Year Ended December 31, 2018 December 31, 2017 Average Recorded Interest Income Average Recorded Interest Income Investment Recognized Investment Recognized WITH NO RELATED ALLOWANCE RECORDED Home equity $ 404 $ 8 $ 219 $ — One-to-four-family 719 — 56 3 Total real estate loans 1,123 8 275 3 Commercial business loans — — 551 24 1,123 8 826 27 WITH RELATED ALLOWANCE RECORDED One-to-four-family 1,030 28 142 (1) 4 Consumer loans 338 37 281 16 Commercial business loans 1,188 81 — — 2,556 146 423 20 Total $ 3,679 $ 154 $ 1,249 $ 47 __________________________ (1) Includes loans supported by Federal Housing Administration (“FHA”) guarantees. Credit Quality Indicators As part of the Company’s on-going monitoring of credit quality of the loan portfolio, management tracks certain credit quality indicators including trends related to (i) the risk grading of loans, (ii) the level of classified loans, (iii) net charge-offs, (iv) non-performing loans and (v) the general economic conditions in the Company’s markets. The Company utilizes a risk grading matrix to assign a risk grade to its real estate and commercial business loans. Loans are graded on a scale of 1 to 10, with loans in risk grades 1 to 6 considered “Pass” and loans in risk grades 7 to 10 are reported as classified loans in the Company’s allowance for loan loss analysis. A description of the 10 risk grades is as follows: · Grades 1 and 2 - These grades include loans to very high quality borrowers with excellent or desirable business credit. · Grade 3 - This grade includes loans to borrowers of good business credit with moderate risk. · Grades 4 and 5 - These grades include “Pass” grade loans to borrowers of average credit quality and risk. · Grade 6 - This grade includes loans on management’s “Watch” list and is intended to be utilized on a temporary basis for “Pass” grade borrowers where frequent and thorough monitoring is required due to credit weaknesses and where significant risk-modifying action is anticipated in the near term. · Grade 7 - This grade is for “Other Assets Especially Mentioned (OAEM)” in accordance with regulatory guidelines and includes borrowers where performance is poor or significantly less than expected. · Grade 8 - This grade includes “Substandard” loans in accordance with regulatory guidelines which represent an unacceptable business credit where a loss is possible if loan weakness is not corrected. · Grade 9 - This grade includes “Doubtful” loans in accordance with regulatory guidelines where a loss is highly probable. · Grade 10 - This grade includes “Loss” loans in accordance with regulatory guidelines for which total loss is expected and when identified are charged off. Consumer, Home Equity and One-to-Four-Family Real Estate Loans Homogeneous loans are risk rated based upon the Federal Financial Institutions Examination Council’s Uniform Retail Credit Classification and Account Management Policy. Loans classified under this policy at the Company are consumer loans which include indirect home improvement, solar, marine, other consumer, and one-to-four-family first and second liens. Under the Uniform Retail Credit Classification Policy, loans that are current or less than 90 days past due are graded “Pass” and risk graded “4” or “5” internally. Loans that are past due more than 90 days are classified “Substandard” risk graded “8” internally until the loan has demonstrated consistent performance, typically six months of contractual payments. Closed-end loans that are 120 days past due and open-end loans that are 180 days past due are charged off based on the value of the collateral less cost to sell. The following tables summarize risk rated loan balances by category at the dates indicated: December 31, 2018 Special Pass Watch Mention Substandard Doubtful Loss (1 - 5) (6) (7) (8) (9) (10) Total REAL ESTATE LOANS Commercial $ 203,557 $ 1,142 $ — $ — $ — $ — $ 204,699 Construction and development 244,577 2,729 — — — — 247,306 Home equity 39,846 — 183 229 — — 40,258 One-to-four-family 247,575 207 63 1,552 — — 249,397 Multi-family 103,447 1,216 — — — — 104,663 Total real estate loans 839,002 5,294 246 1,781 — — 846,323 CONSUMER LOANS Indirect home improvement 167,426 — — 367 — — 167,793 Solar 44,392 — — 41 — — 44,433 Marine 57,804 — — 18 — — 57,822 Other consumer 5,415 — 8 2 — — 5,425 Total consumer loans 275,037 — 8 428 — — 275,473 COMMERCIAL BUSINESS LOANS Commercial and industrial 124,089 8,813 — 5,784 — — 138,686 Warehouse lending 65,756 — — — — — 65,756 Total commercial business loans 189,845 8,813 — 5,784 — — 204,442 Total loans receivable, gross $ 1,303,884 $ 14,107 $ 254 $ 7,993 $ — $ — $ 1,326,238 December 31, 2017 Special Pass Watch Mention Substandard Doubtful Loss (1 - 5) (6) (7) (8) (9) (10) Total REAL ESTATE LOANS Commercial $ 62,057 $ — $ 1,554 $ — $ — $ — $ 63,611 Construction and development 143,068 — — — — — 143,068 Home equity 25,138 — — 151 — — 25,289 One-to-four-family 163,513 — — 142 — — 163,655 Multi-family 44,451 — — — — — 44,451 Total real estate loans 438,227 — 1,554 293 — — 440,074 CONSUMER LOANS Indirect home improvement 129,981 — — 195 — — 130,176 Solar 41,049 — — — — — 41,049 Marine 35,397 — — — — — 35,397 Other consumer 1,998 — — 48 — — 2,046 Total consumer loans 208,425 — — 243 — — 208,668 COMMERCIAL BUSINESS LOANS Commercial and industrial 76,942 — 425 5,939 — — 83,306 Warehouse lending 40,724 673 — — — — 41,397 Total commercial business loans 117,666 673 425 5,939 — — 124,703 Total loans receivable, gross $ 764,318 $ 673 $ 1,979 $ 6,475 $ — $ — $ 773,445 At December 31, 2018, there were no troubled debt restructured loans (“TDRs”) that were modified in the previous 12 months that subsequently defaulted in the reporting year. The Company had no TDRs at December 31, 2018. Related Party Loans Certain directors and executive officers or their related affiliates are customers of and have had banking transactions with the Company. Total loans to directors, executive officers, and their affiliates are subject to regulatory limitations. Outstanding loan balances were as follows and were within regulatory limitations: At December 31, 2018 2017 Beginning balance $ 655 $ 313 Additions 2,688 351 Repayments (18) (9) Ending balance $ 3,325 $ 655 The aggregate maximum loan balances of extended credit were $3.6 million and $819,000 at December 31, 2018 and 2017, respectively, and includes the ending balances from the tables above. These loans and lines of credit were made in compliance with applicable laws on substantially the same terms (including interest rates and collateral) as those prevailing at the time for comparable transactions with other persons and do not involve more than the normal risk of collectability.

Servicing Rights

Servicing Rights	12 Months Ended
	Dec. 31, 2018
Fair Value, Off-balance Sheet Risk [Abstract]
Servicing Rights	NOTE 5 - SERVICING RIGHTS Loans serviced for others are not included on the Consolidated Balance Sheets. The unpaid principal balances of permanent loans serviced for others were $1. 19 billion and $778.9 million at December 31, 2018 and 2017, respectively and are shown at the lower of cost or market. The following table summarizes servicing rights activity for the years ended December 31, 2018 and 2017: 2018 2017 Beginning balance $ 6,795 $ 8,459 Additions 5,971 5,075 Sales — (4,751) Servicing rights amortized (2,337) (1,988) Ending balance $ 10,429 $ 6,795 The fair market value of the servicing rights’ assets was $14.6 million and $8.6 million at December 31, 2018 and December 31, 2017, respectively. Fair value adjustments to servicing rights are mainly due to market-based assumptions associated with discounted cash flows, loan prepayment speeds, and changes in interest rates. A significant change in prepayments of the loans in the servicing portfolio could result in significant changes in the valuation adjustments, thus creating potential volatility in the carrying amount of servicing rights. The following provides valuation assumptions used in determining the fair value of MSR at the dates indicated: At December 31, 2018 2017 Key assumptions: Weighted average discount rate 9.5 % 9.5 % Conditional prepayment rate (“CPR”) 9.4 % 10.9 % Weighted average life in years 7.7 6.7 Key economic assumptions and the sensitivity of the current fair value for single family MSR to immediate adverse changes in those assumptions at December 31, 2018 and December 31, 2017 were as follows: December 31, 2018 December 31, 2017 Aggregate portfolio principal balance $ 1,186,858 $ 775,093 Weighted average rate of note 4.3 % % At December 31, 2018 Base 0.5% Adverse Rate Change 1.0% Adverse Rate Change Conditional prepayment rate 8.8 % 11.6 % 17.7 % Fair value MSR $ 14,218 $ 12,723 $ 10,358 Percentage of MSR 1.2 % 1.1 % 0.9 % Discount rate 9.6 % 10.1 % 10.6 % Fair value MSR $ 14,218 $ 13,912 $ 13,617 Percentage of MSR 1.2 % 1.2 % 1.2 % At December 31, 2017 Base 0.5% Adverse Rate Change 1.0% Adverse Rate Change Conditional prepayment rate 10.9 % 17.7 % 24.5 % Fair value MSR $ 8,602 $ 6,811 $ 5,614 Percentage of MSR 1.1 % 0.9 % 0.7 % Discount rate 9.6 % 10.1 % 10.6 % Fair value MSR $ 8,602 $ 8,433 $ 8,271 Percentage of MSR 1.1 % 1.1 % 1.1 % The above table shows the sensitivity to market rate changes for the par rate coupon for a conventional one-to-four-family FNMA, FHLMC, GNMA, or FHLB serviced home loan. The above table references a 50 basis point and 100 basis point decrease in note rates. These sensitivities are hypothetical and should be used with caution as the tables above demonstrate the Company’s methodology for estimating the fair value of MSR which is highly sensitive to changes in key assumptions. For example, actual prepayment experience may differ and any difference may have a material effect on MSR fair value. Changes in fair value resulting from changes in assumptions generally cannot be extrapolated because the relationship of the change in the assumption to the change in fair value may not be linear. Also, in these tables, the effects of a variation in a particular assumption on the fair value of the MSR is calculated without changing any other assumption; in reality, changes in one factor may be associated with changes in another (for example, decreases in market interest rates may provide an incentive to refinance; however, this may also indicate a slowing economy and an increase in the unemployment rate, which reduces the number of borrowers who qualify for refinancing), which may magnify or counteract the sensitivities. Thus, any measurement of MSR fair value is limited by the conditions existing and assumptions made as a particular point in time. Those assumptions may not be appropriate if they are applied to a different point in time. The Company recorded $2.4 million and $2.2 million of gross contractually specified servicing fees, late fees, and other ancillary fees resulting from servicing of mortgage and commercial loans for the years ended December 31, 2018 and 2017, respectively. The income, net of amortization, is reported in noninterest income on the Consolidated Statements of Income.

Premises and Equipment

Premises and Equipment	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Premises and Equipment	NOTE 6 - PREMISES AND EQUIPMENT Premises and equipment at December 31, 2018 and 2017 were as follows: 2018 2017 Land $ 5,227 $ 2,028 Buildings 16,772 8,611 Furniture, fixtures, and equipment 12,039 10,105 Leasehold improvements 2,422 2,108 Building improvements 5,897 4,545 Projects in process 674 189 Subtotal 43,031 27,586 Less accumulated depreciation and amortization (13,921) (12,128) Total $ 29,110 $ 15,458 Depreciation and amortization expense for these assets totaled $1.8 million and $1.6 million for the years ended December 31, 2018 and 2017, respectively. The Company leases premises and equipment under operating leases. Minimum net rental commitments under non-cancelable leases, having an original or remaining term of more than one year for future years, were as follows: Years Ending December 31, 2019 $ 1,312 2020 1,005 2021 855 2022 749 2023 390 Thereafter 1,228 Total $ 5,539 Certain leases contain renewal options from five to 10 years and escalation clauses based on increases in property taxes and other costs. Rental expense of leased premises and equipment was $1.2 million and $1.1 million for the years ended December 31, 2018 and 2017, respectively, which is included in occupancy expense.

Other Real Estate Owned

Other Real Estate Owned	12 Months Ended
	Dec. 31, 2018
Banking and Thrift [Abstract]
Other Real Estate Owned	NOTE 7 - OTHER REAL ESTATE OWNED The following table presents the activity related to OREO at and for the years ended December 31: At or For the Year Ended December 31, 2018 2017 Beginning balance $ — $ — Additions 689 — Ending balance $ 689 $ — During 2018, there was $689,000 in OREO properties acquired through the Anchor Acquisition and associated holding costs of $2,000 for the year ended December 31, 2018. There were $261,000 in mortgage loans collateralized by residential real estate property in the process of foreclosure at December 31, 2018, and there were no loans in the process of foreclosure at December 31, 2017.

Deposits

Deposits	12 Months Ended
	Dec. 31, 2018
Banking and Thrift [Abstract]
Deposits	NOTE 8 - DEPOSITS Deposits are summarized as follows at December 31: December 31, December 31, 2018 (1)(2) 2017 (1) Noninterest-bearing checking $ 221,107 $ 177,739 Interest-bearing checking 151,103 119,872 Savings 122,344 72,082 Money market (3) 282,595 228,742 Certificates of deposit less than $100,000 (4) 243,193 111,489 Certificates of deposit of $100,000 through $250,000 154,095 77,934 Certificates of deposit of $250,000 and over (5) 86,357 32,833 Escrow accounts related to mortgages serviced 13,425 9,151 Total $ 1,274,219 $ 829,842 ________________________ (1) Includes $120.0 million and $134.6 million of deposits at December 31, 2018 and 2017, respectively, remaining from the January 22, 2016 purchase of four retail bank branches from Bank of America, N.A. (the “Branch Purchase”). (2) On November 15, 2018, the Company completed the Anchor Acquisition and acquired approximately $357.9 million in deposits. (3) Includes $1,000 of brokered deposits at December 31, 2018 and $6.5 million at December 31, 2017. (4) Includes $116.7 million and $59.3 million of brokered deposits at December 31, 2018 and 2017, respectively. (5) Time deposits that meet or exceed the FDIC insurance limit. Scheduled maturities of time deposits at December 31, 2018 for future years ending are as follows: At December 31, 2018 Maturing in 2019 $ 290,822 Maturing in 2020 117,077 Maturing in 2021 37,277 Maturing in 2022 29,472 Maturing in 2023 8,997 Thereafter — Total $ 483,645 Interest expense by deposit category for the years ended December 31, 2018 and 2017 is as follows: 2018 2017 Interest-bearing checking $ 227 $ 128 Savings and money market 2,054 1,260 Certificates of deposit 5,040 2,532 Total $ 7,321 $ 3,920 The Company had related party deposits of approximately $6.2 million and $2.1 mill ion at December 31, 2018 and 2017, respectively, which includes deposits held for directors and executive officers.

Debt

Debt	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Debt	NOTE 9 - DEBT Borrowings The Bank is a member of the FHLB of Des Moines, which entitles it to certain benefits including a variety of borrowing options consisting of a secured credit line that allows both fixed and variable rate advances. The FHLB borrowings at December 31, 2018 and 2017, consisted of a warehouse securities credit line (“securities line”), which allows advances with interest rates fixed at the time of borrowing and a warehouse federal funds (“Fed Funds”) advance, which allows daily advances at variable interest rates. Credit capacity is primarily determined by the value of assets collateralized at the FHLB, funds on deposit at the FHLB, and stock owned by the Bank. Credit is limited to 45% of the Company’s total assets and available pledged assets. The Bank entered into an Advanced, Pledges and Security Agreement with the FHLB for which specific loans are pledged to secure these credit lines. At December 31, 2018, loans of approximately $355.5 million were pledged to the FHLB with a borrowing capacity, net of advances of $120.0 million. In addition, all FHLB stock owned by the Company is collateral for credit lines. The Bank maintains a short-term borrowing line with the FRB with total credit based on eligible collateral. The Bank can borrow under the Term Auction or Term Facility at rates published by the San Francisco FRB. At December 31, 2018 and 2017, the Bank had approximately $265.2 million in pledged consumer loans with a Term Auction or Term Facility borrowing capacity of $127.7 million and $99.1 million, respectively, of which none was outstanding at either date. The Bank also had $51.0 million unsecured Fed Funds lines of credit with other financial institutions of which none was outstanding at December 31, 2018. Advances on these lines at December 31, 2018 and 2017 were as follows: 2018 2017 Federal Home Loan Bank - (interest rates ranging from 1.15% to 2.87% and 0.96% to 1.73% at December 31, 2018 and 2017, respectively) $ 137,149 $ 7,529 Total $ 137,149 $ 7,529 Subordinated Note On October 15, 2015 (the “Closing Date”), FS Bancorp, Inc. issued an unsecured subordinated term note in the aggregate principal amount of $10.0 million due October 1, 2025 (the “Subordinated Note”) pursuant to a Subordinated Loan Agreement with Community Funding CLO, Ltd. The Subordinated Note bears interest at an annual interest rate of 6.50%, payable by the Company quarterly in arrears on January 1, April 1, July 1 and October 1 of each year, commencing on the first such date following the Closing Date and on the maturity date. The Subordinated Note will mature on October 1, 2025 but may be prepaid at the Company’s option and with regulatory approval at any time on or after five years after the Closing Date or at any time upon certain events, such as a change in the regulatory capital treatment of the Subordinated Note or the interest on the Subordinated Note no longer being deductible by the Company for United States federal income tax purposes. The Company contributed $9.0 million of the proceeds from the Subordinated Note as additional capital to the Bank in the fourth quarter of 2015 and used the balance to fund general working capital and operating expenses. The maximum and average outstanding and weighted average interest rates on debt during the years ended December 31, 2018 and 2017 were as follows: 2018 2017 Maximum balance: Federal Home Loan Bank advances and Fed Funds $ 180,025 $ 70,419 Federal Reserve Bank $ — $ 1,000 Fed Funds lines of credit $ 21,016 $ 17,501 Subordinated note $ 10,000 $ 10,000 Average balance: Federal Home Loan Bank advances and Fed Funds $ 96,044 $ 25,635 Federal Reserve Bank $ 5,286 $ 3 Fed Funds lines of credit $ — $ 876 Subordinated note $ 10,000 $ 10,000 Weighted average interest rate: Federal Home Loan Bank advances and Fed Funds 2.02 % 1.26 % Federal Reserve Bank — % 1.75 % Fed Funds lines of credit 1.93 % 1.30 % Subordinated note 6.50 % 6.50 % Scheduled maturities of Federal Home Loan Bank advances were as follows: Interest Year Ending December 31, Balances Rates 2019 $ 121,233 2.36 % 2020 12,284 2.46 % 2021 — — % 2022 — — % 2023 3,632 2.87 % Total $ 137,149

Employee Benefits

Employee Benefits	12 Months Ended
	Dec. 31, 2018
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans	NOTE 10 - EMPLOYEE BENEFITS Employee Stock Ownership Plan On January 1, 2012, the Company established an ESOP for eligible employees of the Company and the Bank. Employees of the Company and the Bank are eligible to participate in the ESOP if they have been credited with at least 1,000 hours of service during the employees’ first 12‑month period and based on the employee’s anniversary date will be vested in the ESOP. The employee will be 100% vested in the ESOP after two years of working at least 1,000 hours in each of those two years. The ESOP borrowed $2.6 million from FS Bancorp, Inc. and used those funds to acquire 259,210 shares of FS Bancorp, Inc. common stock in the open market at an average price of $10.17 per share during the second half of 2012. It is anticipated that the Bank will make contributions to the ESOP in amounts necessary to amortize the ESOP loan payable to FS Bancorp, Inc. over a period of 10 years, bearing interest at 2.30%. Intercompany expenses associated with the ESOP are eliminated in consolidation. Shares purchased by the ESOP with the loan proceeds are held in a suspense account and allocated to ESOP participants on a pro rata basis as principal and interest payments are made by the ESOP to FS Bancorp, Inc. The loan is secured by shares purchased with the loan proceeds and will be repaid by the ESOP with funds from the Bank’s discretionary contributions to the ESOP and earnings on the ESOP assets. Payments of principal and interest are due annually on December 31, the Company’s fiscal year end. On December 31, 2018, the ESOP paid the seventh annual installment of principal in the amount of $269,000, plus accrued interest of $26,000 pursuant to the ESOP loan agreement. As shares are committed to be released from collateral, the Company reports compensation expense equal to the average daily market prices of the shares at December 31, 2018 for the prior 90 days. These shares become outstanding for earnings per share computations. The compensation expense is accrued monthly throughout the year. Dividends on allocated ESOP shares are recorded as a reduction of retained earnings; dividends on unallocated ESOP shares are recorded as a reduction of debt and accrued interest. Compensation expense related to the ESOP for the years ended December 31, 2018 and 2017, was $1.2 million, and $1.4 million, respectively. Shares held by the ESOP at December 31, 2018 and December 31, 2017, were as follows (shown as actual): Balances Balances at December 31, 2018 at December 31, 2017 Allocated shares 176,809 153,049 Committed to be released shares — — Unallocated shares 77,763 103,684 Total ESOP shares 254,572 256,733 Fair value of unallocated shares (in thousands) $ 3,627 $ 5,696 401(k) Plan The Company has a salary deferral 401(k) Plan covering substantially all of its employees. Employees are eligible to participate in the 401(k) plan at the date of hire if they are 18 years of age. Eligible employees may contribute through payroll deductions and are 100% vested at all times in their deferral contributions account. The Company matches 100% for contributions of 1% to 3%, and 50% for contributions of 4% to 5%. There was a $917,000 and $904,000 matching contribution for the years ended December 31, 2018 and 2017, respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
INCOME TAXES
Income Taxes	NOTE 11 - INCOME TAXES The components of income tax expense for the years ended December 31, 2018 and 2017, were as follows: 2018 2017 Provision for income taxes Current $ 3,455 $ 7,212 Deferred 768 (718) Total provision for income taxes $ 4,223 $ 6,494 On December 22, 2017, the U.S. Government enacted the Tax Act. The Tax Act amends the Internal Revenue Code to reduce tax rates and modify policies, credits, and deductions for individuals and businesses. For businesses, the Tax Act reduces the corporate federal income tax rate from a maximum of 35% to a flat 21% rate. The corporate income tax rate reduction was effective January 1, 2018. The Tax Act required a revaluation of the Company’s deferred tax assets and liabilities to account for the future impact of lower corporate tax rates and other provisions of the legislation. As a result of the Company’s revaluation at December 31, 2017, the Company recognized $396,000 in tax benefit due to a net deferred tax liability position. A reconciliation of the effective income tax rate with the federal statutory tax rates at December 31, 2018 and 2017 was as follows: 2018 2017 Amount Rate Amount Rate Income tax provision at statutory rate $ 6,000 21.0 % $ 7,203 35.0 % Tax exempt income (129) (0.5) (218) (1.0) Nondeductible items resulting in increase in tax 279 1.0 — — Decrease in tax resulting from other items (87) (0.3) (487) (2.4) Equity compensation (571) (2.0) — — Executive compensation 135 0.5 — — Bargain purchase gain (1,594) (5.6) — — Income tax rate differential — — (396) (1.9) ESOP 190 0.7 392 1.9 Total $ 4,223 14.8 % $ 6,494 31.6 % Total deferred tax assets and liabilities at December 31, 2018 and 2017 were as follows: 2018 2017 Deferred Tax Assets Net operating loss carryforward $ 1,201 $ — Allowance for loan losses 3,077 1,912 Other real estate owned 127 — Non-accrued loan interest 115 9 Restricted stock awards 54 — Non-qualified stock options 71 — Securities available-for-sale 405 130 Other 473 210 Total deferred tax assets 5,523 2,261 Deferred Tax Liabilities Loan origination costs (626) (870) Servicing rights (2,241) (1,461) Prepaids (166) (52) Stock dividend - FHLB stock (73) (1) Property, plant, and equipment (1,489) (484) Acquisition related costs (1,289) — Total deferred tax liabilities (5,884) (2,868) Net deferred tax liabilities $ (361) $ (607) At December 31, 2018, the Company had a net operating loss carryforward of approximately $5.6 million, which begins to expire in 2034. The Company files a U.S. Federal income tax return and Oregon State return, which are subject to examination by tax authorities for years 2015 and later. At December 31, 2018 and 2017, the Company had no uncertain tax positions. The Company recognizes interest and penalties in tax expense and at December 31, 2018 and 2017, the Company recognized no interest and penalties.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE 12 - COMMITMENTS AND CONTINGENCIES Commitments - The Company is party to financial instruments with off-balance-sheet risk in the normal course of business to meet the financing needs of its customers. These financial instruments include commitments to extend credit. These instruments involve, to varying degrees, elements of credit risk in excess of the amount recognized on the Consolidated Balance Sheets. The Company’s exposure to credit loss in the event of nonperformance by the other party to the financial instrument for commitments to extend credit is represented by the contractual amount of those instruments. The Company uses the same credit policies in making commitments and conditional obligations as it does for on-balance sheet instruments. The following table provides a summary of the Company’s commitments at December 31, 2018 and 2017: 2018 2017 COMMITMENTS TO EXTEND CREDIT REAL ESTATE LOANS Commercial $ 5,836 $ 107 Construction and development 76,889 73,321 One-to-four-family (includes locks for salable loans) 35,714 37,336 Home equity 41,204 32,889 Multi-family 515 438 Total real estate loans 160,158 144,091 CONSUMER LOANS 18,560 10,041 COMMERCIAL BUSINESS LOANS Commercial and industrial 72,880 52,452 Warehouse lending 44,243 78,303 Total commercial business loans 117,123 130,755 Total commitments to extend credit $ 295,841 $ 284,887 Commitments to extend credit are agreements to lend to a customer as long as there is no violation of any condition established in the contract. Since many of the commitments are expected to expire without being drawn upon, the amount of the total commitments do not necessarily represent future cash requirements. The Company evaluates each customer’s creditworthiness on a case-by-case basis. The amount of collateral obtained, if deemed necessary by the Company upon extension of credit, is based on management’s credit evaluation of the party. Collateral held varies, but may include accounts receivable, inventory, property and equipment, residential real estate, and income-producing commercial properties. Unfunded commitments under commercial lines of credit, revolving credit lines and overdraft protection agreements are commitments for possible future extensions of credit to existing customers. These lines of credit are uncollateralized and usually do not contain a specified maturity date and ultimately may not be drawn upon to the total extent to which the Company is committed. The Company has established reserves for estimated losses from unfunded commitments of $299,000 and $253,000 at December 31, 2018 and 2017, respectively. One-to-four-family commitments included in the table above are accounted for as fair value derivatives and do not carry an associated loss reserve. The Company also sells one-to-four-family loans to the FHLB of Des Moines that require a limited level of recourse if the loans default and exceed a certain loss exposure. Specific to that recourse, the FHLB of Des Moines established a first loss account (“FLA”) related to the loans and required a credit enhancement (“CE”) obligation by the Bank to be utilized after the FLA is used. Based on loans sold through December 31, 2018, the total loans sold to the FHLB were $66.0 million with the FLA being $741,000 and the CE obligation at $472,000 or 0.71% of the loans outstanding. Management has established a holdback of 10% of the outstanding CE, or $218,000, which is a part of the off-balance sheet holdback for loans sold. There were no outstanding delinquencies on the loans sold to the FHLB of Des Moines at December 31, 2018 and December 31, 2017. Contingent liabilities for loans held for sale - In the ordinary course of business, loans are sold with limited recourse against the Company and may have to subsequently be repurchased due to defects that occurred during the origination of the loan. The defects are categorized as documentation errors, underwriting errors, early payoff, early payment defaults, breach of representation or warranty, servicing errors, and/or fraud. When a loan sold to an investor without recourse fails to perform according to its contractual terms, the investor will typically review the loan file to determine whether defects in the origination process occurred. If a defect is identified, the Company may be required to either repurchase the loan or indemnify the investor for losses sustained. If there are no such defects, the Company has no commitment to repurchase the loan. The Company has recorded a holdback reserve of $1.0 million to cover loss exposure related to these guarantees for one-to-four-family loans sold into the secondary market at both December 31, 2018 and 2017, which is included in other liabilities in the Consolidated Balance Sheets. The Company has entered into a severance agreement with its Chief Executive Officer. The severance agreement, subject to certain requirements, generally includes a lump sum payment to the Chief Executive Officer equal to 24 months of base compensation in the event their employment is involuntarily terminated, other than for cause or the executive terminates his employment with good reason, as defined in the severance agreement. The Company has entered into change of control agreements with its Chief Financial Officer/Chief Operating Officer, Chief Lending Officer, Chief Credit Officer, Chief Risk Officer, Chief Human Resources Officer, Senior Vice President Compliance Officer, Executive Vice President of Retail Banking and Marketing, and two Executive Vice Presidents of Home Lending. The change of control agreements, subject to certain requirements, generally remain in effect until canceled by either party upon at least 24 months prior written notice. Under the change of control agreements, the executive generally will be entitled to a change of control payment from the Company if the executive is involuntarily terminated within six months preceding or 12 months after a change in control (as defined in the change of control agreements). In such an event, the executives would each be entitled to receive a cash payment in an amount equal to 12 months of their then current salary, subject to certain requirements in the change of control agreements. The Bank received 7,158 shares of Class B common stock in Visa, Inc. as a result of the Visa initial public offering (“IPO”) in March 2008. These Class B shares of stock held by the Bank could be converted to Class A shares at a conversion rate of 1.6298 when all litigation pending as of the date of the IPO is concluded. The conversion rate was reduced during the year as Visa made an additional deposit to their litigation escrow account thus reducing the number of as-converted Class B shares and corresponding conversion rate. At December 31, 2018, the date that litigation will be concluded cannot be determined. Until such time, the stock cannot be redeemed or sold by the Bank; therefore, it is not readily marketable and has a current carrying value of $0. Visa, Inc. Class A stock’s market value at December 31, 2018 and December 31, 2017 was $131.94 per share and $114.02 per share, respectively. As a result of the nature of our activities, the Company is subject to various pending and threatened legal actions, which arise in the ordinary course of business. From time to time, subordination liens may create litigation which requires us to defend our lien rights. In the opinion of management, liabilities arising from these claims, if any, will not have a material effect on our financial position. The Company had no material pending legal actions at December 31, 2018.

Significant Concentration of Cr

Significant Concentration of Credit Risk	12 Months Ended
	Dec. 31, 2018
Risks and Uncertainties [Abstract]
Significant Concentration of Credit Risk	NOTE 13 - SIGNIFICANT CONCENTRATION OF CREDIT RISK Most of the Company’s business and lending activities are primarily with customers located in the greater Puget Sound area and one loan production office located in the Tri-Cities, Washington. The Company originates real estate and consumer loans and has concentrations in these areas, however, indirect home improvement loans are originated through a network of home improvement contractors and dealers located throughout Washington, Oregon, California, Idaho, Arizona, and Colorado. The Company also originates solar loans through contractors and dealers in the state of California. Generally, loans are secured by deposit accounts, personal property, or real estate. Rights to collateral vary and are legally documented to the extent practicable. The concentration on commercial real estate remains below the 300% of Risk Based Capital regulatory threshold and the subset of construction concentration, excluding owner-occupied loans is within Board approved limits. The construction, land development, and other land concentration represents more than 100% of the Bank’s total regulatory capital at 131.2% and is focused on in city, in fill vertical construction financing in King and Snohomish counties. Local economic conditions may affect borrowers’ ability to meet the stated repayment terms.

Regulatory Capital

Regulatory Capital	12 Months Ended
	Dec. 31, 2018
Regulatory Capital Requirements [Abstract]
Regulatory Capital	NOTE 14 - REGULATORY CAPITAL The Bank is subject to various regulatory capital requirements administered by the Federal Reserve and the FDIC. Failure to meet minimum capital requirements can initiate certain mandatory and possibly additional discretionary actions by regulators that, if undertaken, could have a direct material effect on the Company’s consolidated financial statements. Under capital adequacy guidelines of the regulatory framework for prompt corrective action, the Bank must meet specific capital adequacy guidelines that involve quantitative measures of the Bank’s assets, liabilities, and certain off-balance sheet items as calculated under regulatory accounting practices. The Bank’s capital classification is also subject to qualitative judgments by the regulators about components, risk weightings, and other factors. Quantitative measures established by regulation to ensure capital adequacy require the Bank to maintain minimum amounts and ratios (set forth in the table below) of Tier 1 capital (as defined in the regulations) to total average assets (as defined), and minimum ratios of Tier 1 total capital (as defined) and common equity Tier 1 (“CET 1”) capital to risk-weighted assets (as defined). The Bank must maintain minimum total risk-based, Tier 1 risk-based, and Tier 1 leverage, and CET 1 capital ratios as set forth in the table below to be categorized as well capitalized. At December 31, 2018 and December 31, 2017, the Bank was categorized as well capitalized under applicable regulatory requirements. There are no conditions or events since that notification that management believes have changed the Bank’s category. Management believes, at December 31, 2018, that the Company and the Bank met all capital adequacy requirements. The following table compares the Bank’s actual capital amounts and ratios at December 31, 2018 and 2017 to their minimum regulatory capital requirements and well capitalized regulatory capital at those dates (dollars in thousands): To be Well Capitalized Under Prompt For Capital For Capital Adequacy Corrective Actual Adequacy Purposes with Capital Buffer Action Provisions Bank Only Amount Ratio Amount Ratio Amount Ratio Amount Ratio At December 31, 2018 Total risk-based capital (to risk-weighted assets) $ 188,472 13.52 % $ 111,493 8.00 % $ 137,694 9.88 % $ 139,366 10.00 % Tier 1 risk-based capital (to risk-weighted assets) $ 175,824 12.62 % $ 83,620 6.00 % $ 109,820 7.88 % $ 111,493 8.00 % Tier 1 leverage capital (to average assets) $ 175,824 10.67 % $ 65,884 4.00 % $ — N/A $ 82,355 5.00 % CET 1 capital (to risk-weighted assets) $ 175,824 12.62 % $ 62,715 4.50 % $ 88,846 6.38 % $ 90,588 6.50 % At December 31, 2017 Total risk-based capital (to risk-weighted assets) $ 133,967 16.25 % $ 65,965 8.00 % $ 76,272 9.25 % $ 82,456 10.00 % Tier 1 risk-based capital (to risk-weighted assets) $ 123,651 15.00 % $ 49,474 6.00 % $ 59,781 7.25 % $ 65,965 8.00 % Tier 1 leverage capital (to average assets) $ 123,651 12.61 % $ 39,233 4.00 % $ — N/A $ 49,041 5.00 % CET 1 capital (to risk-weighted assets) $ 123,651 15.00 % $ 37,105 4.50 % $ 47,412 5.75 % $ 53,597 6.50 % In addition to the minimum CET 1, Tier 1, total capital, and leverage ratios, the Bank now has to maintain a capital conservation buffer consisting of additional CET 1 capital above the required minimum levels in order to avoid limitations on paying dividends, engaging in share repurchases, and paying discretionary bonuses based on percentages of eligible retained income that could be utilized for such actions. The capital conservation buffer requirement was phased-in on January 1, 2016 when more than 0.625% of risk-weighted assets was required and increased by 0.625% on each subsequent January 1, until fully implemented to an amount more than 2.5% of risk-weighted assets on January 1, 2019. At December 31, 2018, the Bank’s CET 1 capital exceeded the required capital conservation buffer of 1.875%. FS Bancorp, Inc. is a bank holding company registered with the Federal Reserve. Bank holding companies are subject to capital adequacy requirements of the Federal Reserve under the Bank Holding Company Act of 1956, as amended, and the regulations of the Federal Reserve. For a bank holding company with less than $3.0 billion in assets, the capital guidelines apply on a bank only basis, and the Federal Reserve expects the holding company’s subsidiary bank to be well capitalized under the prompt corrective action regulations. If FS Bancorp, Inc. was subject to regulatory guidelines for bank holding companies with $3.0 billion or more in assets at December 31, 2018, FS Bancorp, Inc. would have exceeded all regulatory capital requirements. The regulatory capital ratios calculated for FS Bancorp Inc. at December 31, 2018 were 12.1% for Tier 1 leverage-based capital, 12.4% for Tier 1 risk-based capital, 13.3% for total risk-based capital, and 12.4% for CET 1 capital ratio, and 12.1%, 14.5%, 15.7%, and 14.5% at December 31, 2017, respectively.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	NOTE 15 - FAIR VALUE MEASUREMENTS On January 1, 2018, the Company adopted ASU 2016-01 , Financial Instruments - Overall (Subtopic 825‑10), Recognition and Measurement of Financial Assets and Financial Liabilities, which requires us to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes. The Company determines the fair values of its financial instruments based on the requirements established in Accounting Standards Codification (“ASC”) 820, Fair Value Measurements, which provides a framework for measuring fair value in accordance with U.S. GAAP and requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. ASC 820 defines fair values for financial instruments as the exit price, the price that would be received for an asset or paid to transfer a liability, in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date under current market conditions. The Company’s fair values for financial instruments at December 31, 2018 were determined based on these requirements. Fair values for financial instruments at December 31, 2017 were not retroactively adjusted to reflect exit price. The following definitions describe the levels of inputs that may be used to measure fair value: Level 1 - Inputs to the valuation methodology are quoted prices (unadjusted) for identical assets or liabilities in active markets. Level 2 - Inputs to the valuation methodology include quoted prices for similar assets and liabilities in active markets, and inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument. Level 3 - Inputs to the valuation methodology are unobservable and significant to the fair value measurement. The following methods were used to estimate the fair value of financial instrument on a recurring and nonrecurring basis. Securities Available-for-Sale - The fair value of securities available-for-sale are recorded on a recurring basis. The fair value of investments and mortgage-backed securities are provided by a third-party pricing service. These valuations are based on market data using pricing models that vary by asset class and incorporate available current trade, bid and other market information, and for structured securities, cash flow, and loan performance data. The pricing processes utilize benchmark curves, benchmarking of similar securities, sector groupings, and matrix pricing. Option adjusted spread models are also used to assess the impact of changes in interest rates and to develop prepayment scenarios. Transfers between the fair value hierarchy are determined through the third-party service provider which, from time to time will transfer between levels based on market conditions per the related security. All models and processes used take into account market convention (Level 2). Mortgage Loans Held for Sale - The fair value of loans held for sale reflects the value of commitments with investors and/or the relative price as delivered into a To Be Announced (“TBA”) mortgage-backed security (Level 2). Derivative Instruments - The fair value of the interest rate lock commitments and forward sales commitments are estimated using quoted or published market prices for similar instruments, adjusted for factors such as pull-through rate assumptions based on historical information, where appropriate. TBA mortgage-backed securities are fair valued using similar contracts in active markets (Level 2) while locks and forwards with customers and investors are fair valued using similar contracts in the market and changes in the market interest rates (Level 2 and 3). Impaired Loans - Fair value adjustments to impaired collateral dependent loans are recorded to reflect partial write-downs based on the current appraised value of the collateral or internally developed models, which contain management’s assumptions. Management will utilize discounted cashflow impairment for TDRs when the change in terms result in a discount to the overall cashflows to be received (Level 3). Other Real Estate Owned - Fair value adjustments to OREO are recorded at the lower of carrying amount of the loan or fair value less selling costs. Any write-downs based on the asset’s fair value at the date of acquisition are charged to the allowance for loan losses. After foreclosure, management periodically performs valuations such that the real estate is carried at the lower of its new cost basis or fair value, net of estimated costs to sell (Level 3). The following tables present securities available-for-sale measured at fair value on a recurring basis at the dates indicated: Securities Available-for-Sale Level 1 Level 2 Level 3 Total At December 31, 2018 U.S. agency securities $ — $ 15,887 $ — $ 15,887 Corporate securities — 6,865 — 6,865 Municipal bonds — 14,194 — 14,194 Mortgage-backed securities — 44,836 — 44,836 U.S. Small Business Administration securities — 15,423 — 15,423 Total $ — $ 97,205 $ — $ 97,205 Securities Available-for-Sale Level 1 Level 2 Level 3 Total At December 31, 2017 U.S. agency securities $ — $ 9,115 $ — $ 9,115 Corporate securities — 7,026 — 7,026 Municipal bonds — 12,786 — 12,786 Mortgage-backed securities — 39,734 — 39,734 U.S. Small Business Administration securities — 13,819 — 13,819 Total $ — $ 82,480 $ — $ 82,480 The following table presents mortgage loans held for sale measured at fair value on a recurring basis at the dates indicated: Mortgage Loans Held for Sale Level 1 Level 2 Level 3 Total December 31, 2018 $ — $ 51,195 $ — $ 51,195 December 31, 2017 $ — $ 53,463 $ — $ 53,463 The following tables present the fair value of interest rate lock commitments with customers, individual forward sale commitments with investors, and paired off commitments with investors measured at their fair value on a recurring basis at the dates indicated: Interest Rate Lock Commitments with Customers Level 1 Level 2 Level 3 Total December 31, 2018 $ — $ — $ 503 $ 503 December 31, 2017 $ — $ — $ 726 $ 726 Individual Forward Sale Commitments with Investors Level 1 Level 2 Level 3 Total December 31, 2018 $ — $ (540) $ (34) $ (574) December 31, 2017 $ — $ (65) $ 51 $ (14) Paired Off Commitments with Investors Level 1 Level 2 Level 3 Total December 31, 2018 $ — $ (64) $ — $ (64) December 31, 2017 $ — $ 53 $ — $ 53 The following tables present impaired loans and OREO measured at fair value on a nonrecurring basis for which a nonrecurring change in fair value has been recorded during the reporting period. The amounts disclosed below represent the fair values at the time the nonrecurring fair value measurements were evaluated. Impaired Loans Level 1 Level 2 Level 3 Total December 31, 2018 $ — $ — $ 3,894 $ 3,894 December 31, 2017 $ — $ — $ 1,094 $ 1,094 OREO Level 1 Level 2 Level 3 Total December 31, 2018 $ — $ — $ 689 $ 689 December 31, 2017 $ — $ — $ — $ — Quantitative Information about Level 3 Fair Value Measurements - Shown in the table below is the fair value of financial instruments measured under a Level 3 unobservable input on a recurring and nonrecurring basis at December 31, 2018: Level 3 Significant Range Weighted Fair Value Instruments Valuation Technique Unobservable Inputs (Weighted Average) Average RECURRING Interest rate lock commitments with customers Quoted market prices Pull-through expectations 80% - 99% 95.2 % Individual forward sale commitments with investors Quoted market prices Pull-through expectations 80% - 99% 95.2 % NONRECURRING Impaired loans Fair value of underlying collateral Discount applied to the obtained appraisal 0% - 50% 25.0 % OREO Fair value of collateral Discount applied to the obtained appraisal 0% - 75% 71.1 % An increase in the pull-through rate utilized in the fair value measurement of the interest rate lock commitments with customers and forward sale commitments with investors will result in positive fair value adjustments (and an increase in the fair value measurement). Conversely, a decrease in the pull-through rate will result in a negative fair value adjustment (and a decrease in the fair value measurement). The following table provides a reconciliation of assets and liabilities measured at fair value using significant unobservable inputs (Level 3) on a recurring basis during the years ended December 31, 2018 and 2017. Net change in fair value for gains/ Purchases (losses) relating to Beginning and Sales and Ending items held at end of Balance issuances settlements Balance at end of year 2018 Interest rate lock commitments with customers $ 726 $ 9,722 $ (9,945) $ 503 $ (223) Individual forward sale commitments with investors 51 850 (935) (34) (85) 2017 Interest rate lock commitments with customers $ 818 $ 14,319 $ (14,411) $ 726 $ (92) Individual forward sale commitments with investors 177 141 (267) 51 (126) Gains (losses) on interest rate lock commitments carried at fair value are recorded in other noninterest income. Gains (losses) on forward sale commitments with investors carried at fair value are recorded within other noninterest income. Fair value estimates are based on existing balance sheet financial instruments without attempting to estimate the value of anticipated future business. The fair value has not been estimated for assets and liabilities that are not considered financial instruments. Financial Instruments with Book Value Equal to Fair Value - The fair value of financial instruments that are short-term or reprice frequently and that have little or no risk are considered to have a fair value equal to book value. These instruments include cash and cash equivalents and certificates of deposit at other financial institutions, FHLB stock, BOLI, accrued interest, and off balance sheet instruments. Fair Value Estimates - The following methods and assumptions were used by the Company in estimating the fair values of financial instruments disclosed in following financial instrument table: Loans Receivable, Net - For variable rate loans that re-price frequently and have no significant change in credit risk, fair values are based on carrying values. Fair values for fixed rate loans are estimated using an exit price assumption (Level 3). Servicing Rights - The fair value of mortgage servicing rights are estimated using net present value of expected cash flows using a third party model that incorporates assumptions used in the industry to value such rights, adjusted for factors such as weighted average prepayments speeds based on historical information where appropriate (Level 3). Deposits - The fair value of deposits with no stated maturity date is included at the amount payable on demand. Fair values for fixed rate certificates of deposit are estimated using an exit price assumption (Level 2). Borrowings - The carrying amounts of advances maturing within 90 days approximate their fair values. The fair values of long-term advances are estimated using discounted cash flow analyses based on the Bank’s current incremental borrowing rates for similar types of borrowing arrangements (Level 2). Subordinated Note - The fair value of the Subordinated Note is based upon the average yield of debt issuances for similarly sized issuances (Level 2). The following table provides estimated fair values of the Company’s financial instruments at December 31, 2018 and 2017, whether or not recognized at fair value in the Consolidated Balance Sheets: 2018 2017 Carrying Fair Carrying Fair Amount Value Amount Value Financial Assets Level 1 inputs: Cash and cash equivalents $ 32,779 $ 32,779 $ 18,915 $ 18,915 Certificates of deposit at other financial institutions 22,074 22,074 18,108 18,108 Level 2 inputs: Securities available-for-sale, at fair value 97,205 97,205 82,480 82,480 Loans held for sale, at fair value 51,195 51,195 53,463 53,463 FHLB stock, at cost 9,887 9,887 2,871 2,871 Accrued interest receivable 5,761 5,761 3,566 3,566 Paired off commitments with investors — — 53 53 Level 3 inputs: Loans receivable, gross 1,326,238 1,320,341 773,445 780,551 (1) Servicing rights, held at lower of cost or fair value 10,429 14,593 6,795 8,608 Fair value interest rate locks with customers 503 503 726 726 Individual forward sale commitments with investors — — 51 51 Financial Liabilities Level 2 inputs: Deposits 1,274,219 1,261,096 829,842 838,087 Borrowings 137,149 136,873 7,529 7,498 Subordinated note 9,865 10,242 9,845 10,741 Accrued interest payable 344 344 214 214 Paired off commitments with investors 64 64 — — Individual forward sale commitments with investors 540 540 65 65 Level 3 inputs: Individual forward sale commitments with investors 34 34 — — __________________________ (1) Estimated fair values reported at December 31, 2017 were not retroactively valued at exit price.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Share	NOTE 16 - EARNINGS PER SHARE Basic earnings per share are computed by dividing income available to common shareholders by the weighted average number of common shares outstanding for the year. Diluted earnings per share reflect the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock or resulted in the issuance of common stock that then shared in the earnings of the entity. For earnings per share calculations, the ESOP shares committed to be released are included as outstanding shares for both basic and diluted earnings per share. The following table presents a reconciliation of the components used to compute basic and diluted earnings per share for the years ended December 31, 2018 and 2017. At or For the Year Ended December 31, Numerator: 2018 2017 Net income (in thousands) $ 24,347 $ 14,085 Denominator: Basic weighted average common shares outstanding 3,698,623 3,094,586 Dilutive shares 171,166 197,114 Diluted weighted average common shares outstanding 3,869,789 3,291,700 Basic earnings per share $ 6.58 $ 4.55 Diluted earnings per share $ 6.29 $ 4.28 Potentially dilutive weighted average share options that were not included in the computation of diluted earnings per share because to do so would be anti-dilutive 11,326 — Potential dilutive shares are excluded from computation of earnings per share if their effect is anti-dilutive. Options to purchase common stock shares were not included in the computation of diluted earnings per share because their exercise price resulted in them being anti-dilutive. At December 31, 2018 and 2017, there w ere outstanding options to purchase 290,104 shares and 256,237 shares of the Company's common stock, respectively.

Derivatives

Derivatives	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	NOTE 17 - DERIVATIVES The Company regularly enters into commitments to originate and sell loans held for sale. The Company has established a hedging strategy to protect itself against the risk of loss associated with interest rate movements on loan commitments. The Company enters into contracts to sell forward TBA mortgage-backed securities. These commitments and contracts are considered derivatives but have not been designated as hedging instruments for reporting purposes under U.S. GAAP. Rather, they are accounted for as free-standing derivatives, or economic hedges, with changes in the fair value of the derivatives reported in noninterest income. The Company recognizes all derivative instruments as either other assets or other liabilities on the Consolidated Balance Sheets and measures those instruments at fair value. The following tables summarize the Company’s derivative instruments at the dates indicated: December 31, 2018 Fair Value Notional Asset Liability Fallout adjusted interest rate lock commitments with customers $ 29,432 $ 503 $ — Mandatory and best effort forward commitments with investors 24,776 — 34 Forward TBA mortgage-backed securities 51,500 — 540 TBA mortgage-backed securities forward sales paired off with investors 6,500 — 64 December 31, 2017 Fair Value Notional Asset Liability Fallout adjusted interest rate lock commitments with customers $ 31,951 $ 726 $ — Mandatory and best effort forward commitments with investors 12,505 51 — Forward TBA mortgage-backed securities 66,500 — 65 TBA mortgage-backed securities forward sales paired off with investors 36,500 53 — At December 31, 2018 and 2017, the Company had $51.5 million and $66.5 million of TBA trades with counterparties that required margin collateral of $460,000 and $75,000, respectively. This collateral is included in interest-bearing deposits at other financial institutions on the Consolidated Balance Sheets. Changes in the fair value of the derivatives recognized in other noninterest income on the Consolidated Statements of Income and included in gain on sale of loans resulted in a net (loss) gain of $(702,000) and $2.3 million for the years ended December 31, 2018 and 2017, respectively.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	NOTE 18 - STOCK-BASED COMPENSATION Stock Options and Restricted Stock On May 17, 2018, the shareholders of FS Bancorp, Inc. approved the 2018 Equity Incentive Plan (the “2018 Plan”) that authorizes 650,000 shares of the Company’s common stock to be awarded. The 2018 Plan provides for the grant of incentive stock options, non-qualified stock options, and up to 163,000 restricted stock awards (“RSAs”) to directors, emeritus directors, officers, employees or advisory directors of the Company. On August 15, 2018, the Company awarded grants of 25,000 RSAs and 100,000 stock options with an exercise price equal to the market price of FS Bancorp’s common stock at the grant date of $58.60 per share. In September 2013, the shareholders of FS Bancorp, Inc. approved the FS Bancorp, Inc. 2013 Equity Incentive Plan (“2013 Plan”). The Plan provides for the grant of stock options and restricted stock awards (“RSAs”). The 2013 Plan authorizes the grant of stock options totaling 324,013 shares of common stock to Company directors and employees of which 322,000 option share awards were granted with an exercise price equal to the market price of FS Bancorp’s common stock at the grant date of May 8, 2014, of $16.89 per share. The 2013 Plan authorizes the grant of RSAs totaling 129,605 shares to Company directors, advisory directors, emeritus directors, officers, and employees, and 125,105 shares were granted on May 8, 2014 at a grant date fair value of $16.89 per share. The remaining 4,500 RSAs were granted January 1, 2016 at a grant date fair value of $26.00 per share. Total share-based compensation expense for both plans was $767,000 for the year ended December 31, 2018, and $634,000 for the year ended December 31, 2017. The related income tax benefit was $161,000 for the year ended December 31, 2018, and $222,000 for 2017. Stock Options Both plans consist of stock option awards that may be granted as incentive stock options or non-qualified stock options. Options typically vest over a period of five years with 20% vesting on the anniversary date of each grant date as long as the award recipient remains in service to the Company. The options are exercisable after vesting for up to the remaining term of the original grant. The maximum term of the options granted is 10 years. Any unexercised stock options will expire 10 years after the grant date or sooner in the event of the award recipient’s termination of service with the Company or the Bank. At December 31, 2018, there were 387,000 and 6,013 option share awards available to be granted under the 2018 Plan and the 2013 Plan, respectively. The fair value of each option award is estimated on the grant date using a Black-Scholes Option pricing model that uses the following assumptions. The dividend yield is based on the current quarterly dividend in effect at the time of the grant. Historical employment data is used to estimate the forfeiture rate. The Company elected to use Staff Accounting Bulletin 107, simplified expected term calculation for the “Share-Based Payments” method permitted by the SEC to calculate the expected term. This method uses the vesting term of an option along with the contractual term, setting the expected life at 6.5 years. The fair value of options granted was determined using the following weighted-average assumptions as of the grant date for the year ended December 31, 2018. There were no options granted in 2017. Year Ended December 31, 2018 Dividend yield Expected volatility Risk-free interest rate Expected term in years 6.5 Weighted-average grant date fair value per option granted $ 13.22 The following table presents a summary of the Company’s stock option plan awards during the year ended December 31, 2018 (shown as actual): Weighted-Average Weighted- Remaining Average Contractual Term In Aggregate Shares Exercise Price Years Intrinsic Value Outstanding at January 1, 2018 256,237 $ 16.89 6.36 $ 9,655,010 Granted 100,000 58.60 — — Less exercised 66,133 $ 16.89 — $ 2,453,314 Forfeited or expired — — — — Outstanding at December 31, 2018 290,104 $ 31.27 6.83 $ 4,940,803 Expected to vest, assuming a 0.31% annual forfeiture rate (1) 289,226 $ 31.19 6.82 $ 4,939,069 Exercisable at December 31, 2018 129,304 $ 16.89 5.36 $ 3,360,611 (1) Forfeiture rate has been calculated and estimated to assume a forfeiture of 3.1% of the options forfeited over 10 years. At December 31, 2018, there was $1.3 million of total unrecognized compensation cost related to nonvested stock options granted under both plans. The cost is expected to be recognized over the remaining weighted-average vesting period of 4.4 years. The total intrinsic value of options exercised for the years ended December 31, 2018 and 2017 was $2.5 million and $1.1 million, respectively. Restricted Stock Awards The RSAs’ fair value is equal to the value on the grant date. Compensation expense is recognized over the vesting period of the awards based on the fair value of the restricted stock. Shares in the 2013 Plan awarded as restricted stock typically vest ratably over a three-year period for directors and a five-year period for employees, beginning at the grant date, and for the 2018 Plan, shares typically vest ratably over a five-year period for both directors and employees beginning at the grant date. Any unvested RSAs will expire after vesting or sooner in the event of the award recipient’s termination of service with the Company or the Bank. The following table presents a summary of the Company’s nonvested awards during the year ended December 31, 2018 (shown as actual): Weighted-Average Grant-Date Fair Value Nonvested Shares Shares Per Share Nonvested at January 1, 2018 36,842 $ 17.63 Granted 25,000 58.60 Less vested 18,421 $ 17.63 Forfeited or expired — — Nonvested at December 31, 2018 43,421 $ 41.22 At December 31, 2018, there was $1.5 million of total unrecognized compensation costs related to nonvested shares granted under both plans as RSAs. The cost is expected to be recognized over the remaining weighted-average vesting period of 4.3 years. The total fair value of shares vested for the years ended December 31, 2018 and 2017 was $1.1 million and $1.4 million, respectively.

Business Segments

Business Segments	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Business Segments	NOTE 19 - BUSINESS SEGMENTS The Company’s business segments are determined based on the products and services provided, as well as the nature of the related business activities, and they reflect the manner in which financial information is currently evaluated by management. This process is dynamic and is based on management’s current view of the Company’s operations and is not necessarily comparable with similar information for other financial institutions. We define our business segments by product type and customer segment which we have organized into two lines of business: commercial and consumer banking and home lending. We use various management accounting methodologies to assign certain income statement items to the responsible operating segment, including: · a funds transfer pricing (“FTP”) system, which allocates interest income credits and funding charges between the segments, assigning to each segment a funding credit for its liabilities, such as deposits, and a charge to fund its assets; · a cost per loan serviced allocation based on the number of loans being serviced on the balance sheet and the number of loans serviced for third parties; · an allocation based upon the approximate square footage utilized by the home lending segment in Company owned locations; · an allocation of charges for services rendered to the segments by centralized functions, such as corporate overhead, which are generally based on the number of full time employees (“FTEs”) in each segment; and · an allocation of the Company’s consolidated income taxes which are based on the effective tax rate applied to the segment’s pretax income or loss. The FTP methodology is based on management’s estimated cost of originating funds including the cost of overhead for deposit generation. A description of the Company’s business segments and the products and services that they provide is as follows: Commercial and Consumer Banking Segment The commercial and consumer banking segment provides diversified financial products and services to our commercial and consumer customers through Bank branches, automated teller machines (“ATM”), online banking platforms, mobile banking apps, and telephone banking. These products and services include deposit products; residential, consumer, business and commercial real estate lending portfolios and cash management services. The Company originates consumer loans, commercial and multi-family real estate loans, construction loans on residential and multi-family construction, and commercial business loans. At December 31, 2018, the Company’s retail deposit branch network consisted of 21 branches in the Pacific Northwest. At December 31, 2018 and December 31, 2017, deposits totaled $1 .27 billion and $829.8 million, respectively. This segment is also responsible for the management of the Company’s investment portfolio and other assets of the Bank. Home Lending Segment The home lending segment originates one-to-four-family residential mortgage loans primarily for sale in the secondary markets as well as originating adjustable rate mortgage (“ARM”) loans held for investment. The majority of the Company’s mortgage loans are sold to or securitized by FNMA, FHLMC, GNMA or FHLB, while the Company retains the right to service these loans. Loans originated under the guidelines of the Federal Housing Administration or FHA, US Department of Veterans Affairs or VA, and United States Department of Agriculture or USDA are generally sold servicing released to a correspondent bank or mortgage company. The Company has the option to sell loans on a servicing-released or servicing-retained basis to securitizers and correspondent lenders. A small percentage of loans are brokered to other lenders. On occasion, the Company may sell a portion of its MSR portfolio and may sell small pools of loans initially originated to be held in the loan portfolio. The Company manages the loan funding and the interest rate risk associated with the secondary market loan sales and the retained one-to-four-family mortgage servicing rights within this business segment. One-to-four-family loans originated for investment are allocated to the home lending segment with a corresponding provision expense and FTP for cost of funds. Segment Financial Results The tables below summarize the financial results for each segment based primarily on the number of FTEs and assets within each segment for the years ended December 31, 2018 and 2017: At or For the Year Ended December 31, 2018 Home Lending Commercial and Consumer Banking Total Condensed income statement: Net interest income (1) $ 3,324 $ 48,774 $ 52,098 Provision for loan losses (224) (1,316) (1,540) Noninterest income (2) 14,025 12,825 26,850 Noninterest expense (15,894) (32,944) (48,838) Income before provision for income taxes 1,231 27,339 28,570 Provision for income taxes (182) (4,041) (4,223) Net income $ 1,049 $ 23,298 $ 24,347 Total assets (3) $ 246,280 $ 1,375,364 $ 1,621,644 Total average assets at period end $ 229,661 $ 945,052 $ 1,174,713 FTEs 115 309 424 At or For the Year Ended December 31, 2017 Home Lending Commercial and Consumer Banking Total Condensed income statement: Net interest income (1) $ 2,587 $ 38,661 $ 41,248 Provision for loan losses (287) (463) (750) Noninterest income 18,973 5,101 24,074 Noninterest expense (17,052) (26,941) (43,993) Income before provision for income taxes 4,221 16,358 20,579 Provision for income taxes (1,332) (5,162) (6,494) Net income $ 2,889 $ 11,196 $ 14,085 Total assets $ 220,353 $ 761,430 $ 981,783 Total average assets at period end $ 203,379 $ 720,202 $ 923,581 FTEs 119 207 326 ___________________________ (1) Net interest income is the difference between interest earned on assets and the cost of liabilities to fund those assets. Interest earned includes actual interest earned on segment assets and, if the segment has excess liabilities, interest credits for providing funding to the other segment. The cost of liabilities includes interest expense on segment liabilities and, if the segment does not have enough liabilities to fund its assets, a funding charge based on the cost of assigned liabilities to fund segment assets. (2) Barg ain purchase gain of $7.4 million was included in the commercial and consumer banking segment. (3) Increase from prior year relates primarily to the Anchor Acquisition and organic growth.

Revenue From Contracts With Cus

Revenue From Contracts With Customers	12 Months Ended
	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customers	NOTE 20 - REVENUE FROM CONTRACTS WITH CUSTOMERS As noted in Note 1, the Company adopted the provisions of ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), on January 1, 2018 and all subsequent ASUs that modified Topic 606. Results for reporting periods beginning after December 31, 2017 are presented under Topic 606, while prior period amounts have not been adjusted and continue to be reported in accordance with Topic 605. Revenue Recognition In accordance with Topic 606, revenues are recognized when control of promised goods or services is transferred to customers in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Topic 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of Topic 606, the Company assesses the goods or services that are promised within each contract and identifies those that contain performance obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. Based on the adoption of Topic 606, the Company’s revenue recognition was unchanged in 2018 compared to 2017. All of the Company’s revenue from contracts with customers in scope of ASC 606 is recognized in noninterest income and included in our commercial and consumer banking segment. For the year ended December 31, 2018, the Company recognized $2.5 million in total deposit fees, which included $1.2 million of debit card interchange fees and $561,000 of fees from non-sufficient funds, both considered within the scope of ASC 606, and $25.1 million of noninterest income considered not within the scope of ASC 606. Deposit Fees The Bank earns fees from its deposit customers for account maintenance, transaction-based and overdraft services. Account maintenance fees consist primarily of account fees and analyzed account fees charged on deposit accounts on a monthly basis. The performance obligation is satisfied and the fees are recognized on a monthly basis as the service period is completed. Transaction-based fees on deposits accounts are charged to deposit customers for specific services provided to the customer, such as non-sufficient funds fees, overdraft fees, and wire fees. The performance obligation is completed as the transaction occurs and the fees are recognized at the time each specific service is provided to the customer. Debit Interchange Income Debit and ATM interchange income represent fees earned when a debit card issued by the Bank is used. The Bank earns interchange fees from debit cardholder transactions through the Visa payment network. Interchange fees from cardholder transactions represent a percentage of the underlying transaction value and are recognized daily, concurrently with the transaction processing services provided to the cardholder. The performance obligation is satisfied and the fees are earned when the cost of the transaction is charged to the cardholders’ debit card. Certain expenses directly associated with the debit card are recorded on a net basis with the interchange income.

Goodwill And Other Intangible A

Goodwill And Other Intangible Assets	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	NOTE 21 - GOODWILL AND OTHER INTANGIBLE ASSETS Goodwill and certain other intangibles generally arise from business combinations accounted for under the purchase method of accounting. Goodwill totaled $2.3 million at December 30, 2018 and 2017, and represents the excess of the total acquisition price paid over the fair value of the assets acquired, net of the fair values of liabilities assumed as a result of the Branch Purchase in 2016. Goodwill is not amortized but is evaluated for impairment on an annual basis at December 31 of each year or whenever events or changes in circumstances indicate the carrying value may not be recoverable. The Company performed an impairment analysis at December 31, 2018, and 2017 and determined that no impairment of goodwill existed. The following table summarizes the changes in the Company’s other intangible assets and represents the CDI for the years ended December 31, 2018, and December 31, 2017. Other Intangible Assets Accumulated Gross CDI Amortization Net CDI Balance, December 31, 2016 $ 2,239 $ (522) $ 1,717 Amortization — (400) (400) Balance, December 31, 2017 2,239 (922) 1,317 Amortization — (307) (307) Additions as a result of the Anchor Acquisition 5,251 (44) 5,207 Balance, December 31, 2018 $ 7,490 $ (1,273) $ 6,217 The CDI represents the fair value of the core deposit base acquired in business combinations. The CDI will be amortized on a straight-line basis over 10 years for the CDI related to the Anchor Acquisition and on an accelerated basis over approximately nine years for the CDI related to the Branch Purchase. Total amortization expense was $351,000 for the year ended December 31, 2018, and $400,000 for the same period in 2017. Amortization expense for the CDI is expected to be as follows at December 31, 2018: 2019 760 2020 706 2021 691 2022 691 2023 691 Thereafter 2,678 Total $ 6,217

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Financial Statement Presentation	Financial Statement Presentation - The consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) and with prevailing practices within the banking and securities industries. In preparing such financial statements, management is required to make certain estimates and judgments that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the balance sheet and the reported amounts of revenues and expenses for the reporting period. Actual results could differ significantly from those estimates. Material estimates that are particularly susceptible to significant change relate to the determination of the allowance for loan and lease losses, fair value of financial instruments, the valuation of servicing rights, and the deferred income taxes. Amounts presented in the consolidated financial statements and footnote tables are rounded and presented to the nearest thousands of dollars except per share amounts. If the amounts are above $1.0 million, they are rounded one decimal point, and if they are above $1.0 billion, they are rounded two decimal points. Certain prior year amounts have been reclassified to conform to the 2018 presentation with no change to consolidated net income or stockholders’ equity previously reported.
Principles of Consolidation	Principles of Consolidation - The consolidated financial statements include the accounts of FS Bancorp, Inc. and its wholly owned subsidiary, 1st Security Bank of Washington. All material intercompany accounts have been eliminated in consolidation.
Segment Reporting	Segment Reporting - The Company operates in two business segments through the Bank: commercial and consumer banking and home lending. The Company’s business segments are determined based on the products and services provided, as well as the nature of the related business activities, and they reflect the manner in which financial information is regularly reviewed for the purpose of allocating resources and evaluating performance of the Company’s businesses. The results for these business segments are based on management’s accounting process, which assigns income statement items and assets to each responsible operating segment. This process is dynamic and is based on management’s view of the Company’s operations. See “Note 19 - Business Segments.”
Subsequent Events	Subsequent Events - The Company has evaluated events and transactions subsequent to December 31, 2018 for potential recognition or disclosure.
Cash and Cash Equivalents	Cash and Cash Equivalents - Cash and cash equivalents include cash and due from banks, and interest-bearing balances due from other banks and the Federal Reserve Bank of San Francisco (“FRB”) and have an original maturity of 90 days or less at the time of purchase. At times, cash balances may exceed Federal Deposit Insurance Corporation (“FDIC”) insured limits. At December 31, 2018 and 2017, the Company had $25,000 and $15,000, respectively, of cash and due from banks and interest-bearing deposits at other financial institutions in excess of FDIC insured limits. Because the Company places these deposits with major financial institutions and monitors the financial condition of these institutions, management believes the risk of loss to any deposits in excess of FDIC limits to be minimal.
Securities Available-for-Sale	Securities Available-for-Sale - Securities available-for-sale consist of debt securities that the Company has the intent and ability to hold for an indefinite period, but not necessarily to maturity. Such securities may be sold to implement the Company’s asset/liability management strategies and in response to changes in interest rates and similar factors. Securities available-for-sale are reported at fair value. Realized gains and losses on securities available-for-sale, determined using the specific identification method, are included in results of operations. Amortization of premium and accretion of discounts are recognized in interest income over the period to maturity. Unrealized holding gains and losses, net of the related deferred tax effect, are reported as a net amount in a separate component of equity entitled accumulated other comprehensive income. Unrealized losses that are deemed to be other than temporary are reflected in results of operations. Any declines in the values of these securities that are considered to be other-than-temporary-impairment (“OTTI”) and credit-related are recognized in earnings. Noncredit-related OTTI on securities not expected to be sold is recognized in other comprehensive income. The review for OTTI is conducted on an ongoing basis and takes into account the severity and duration of the impairment, recent events specific to the issuer or industry, fair value in relationship to cost, extent and nature of change in fair value, creditworthiness of the issuer including external credit ratings and recent downgrades, trends and volatility of earnings, current analysts’ evaluations, and other key measures. In addition, the Company does not intend to sell the securities and it is more likely than not that we will not be required to sell the securities before recovery of their amortized cost basis. In doing this, we take into account our balance sheet management strategy and consideration of current and future market conditions. Dividends and interest income are recognized when earned.
Federal Home Loan Bank Stock	Federal Home Loan Bank Stock - The Bank’s investment in FHLB stock is carried at cost, which approximates fair value. As a member of the FHLB system, the Bank is required to maintain an investment in capital stock of the FHLB in an amount of $1 .7 million and 4.0% of advances from the FHLB. The Bank’s required minimum level of investment in FHLB stock is based on specific percentages of its outstanding mortgages, total assets, or FHLB advances. At December 31, 2018 and 2017, the Bank’s minimum level of investment requirement in FHLB stock was $9.9 million and $2.9 million, respectively. The Bank was in compliance with the FHLB minimum investment requirement at December 31, 2018 and 2017. Management evaluates FHLB stock for impairment as needed. Management’s determination of whether these investments are impaired is based on its assessment of the ultimate recoverability of cost rather than by recognizing temporary declines in value. The determination of whether a decline affects the ultimate recoverability of cost is influenced by criteria such as (1) the significance of any decline in net assets of the FHLB as compared with the capital stock amount for the FHLB and the length of time this situation has persisted; (2) commitments by the FHLB to make payments required by law or regulation and the level of such payments in relation to the operating performance of the FHLB; (3) the impact of legislative and regulatory changes on institutions and, accordingly, the customer base of the FHLB; and (4) the liquidity position of the FHLB. Based on its evaluation, management determined that there was no impairment of FHLB stock at December 31, 2018 and 2017, respectively.
Loans Held for Sale	Loans Held for Sale - The Bank records all mortgage loans held-for-sale at fair value. Fair value is determined by outstanding commitments from investors or current investor yield requirements calculated on the aggregate loan basis. Origination fees and costs are recognized in earnings at the time of origination. Mortgage loans held for sale are sold with the mortgage service rights either released or retained by the Bank. Gains or losses on sales of mortgage loans are recognized based on the difference between the selling price and the carrying value of the related mortgage loans sold. All sales are made with limited recourse against the Company.
Other Real Estate Owned	Other Real Estate Owned - Other real estate owned (“OREO”) consists of properties or assets acquired through or in lieu of foreclosure, and are recorded initially at fair value less selling costs. Costs relating to development and improvement of the properties or assets are capitalized while costs relating to holding the properties or assets are expensed. Valuations are periodically performed by management, and a charge to earnings is recorded if the recorded value of a property exceeds its estimated net realizable value.
Derivatives	Derivatives - Commitments to fund mortgage loans (interest rate locks) to be sold into the secondary market and forward commitments for the future delivery of these mortgage loans are accounted for as free-standing derivatives. The fair value of the interest rate lock is recorded at the time the commitment to fund the mortgage loan is executed and is adjusted for the expected exercise of the commitments to fund the loans, the Company enters into forward commitments for the future delivery of mortgage loans when interest rate locks are entered. Fair values of these mortgage derivatives are estimated based on changes in mortgage interest rates from the date the interest on the loan is locked. Changes in the fair values of these derivatives are reported in “Gain on sale of loans” on the Consolidated Statements of Income.
Loans Receivable	Loans Receivable - Loans receivable, are stated at the amount of unpaid principal reduced by an allowance for loan losses and net deferred fees or costs. Interest on loans is calculated using the simple interest method based on the daily balance of the principal amount outstanding and is credited to income as earned. Loan fees, net of direct origination costs, are deferred and amortized over the life of the loan using the effective yield method. Interest on loans is accrued daily based on the principal amount outstanding. Generally, the accrual of interest on loans is discontinued when, in management’s opinion, the borrower may be unable to meet payments as they become due or when they are past due 90 days as to either principal or interest (based on contractual terms), unless they are well secured and in the process of collection. All interest accrued but not collected for loans that are placed on non-accrual status or charged off are reversed against interest income. Subsequent collections on a cash basis are applied proportionately to past due principal and interest, unless collectability of principal is in doubt, in which case all payments are applied to principal. Loans are returned to accrual status when the loan is performing according to its contractual terms for at least six months and the collectability of principal and interest is no longer doubtful. The Company charges fees for originating loans. These fees, net of certain loan origination costs, are deferred and amortized to income, based on the interest method, over the loan term. If the loan is repaid prior to maturity, the remaining unamortized net deferred loan origination fee is recognized in income at the time of repayment.
Impaired Loans	Impaired Loans - A loan is considered impaired when it is probable the Company will be unable to collect all contractual principal and interest payments due in accordance with the original or modified terms of the loan agreement. Impaired loans are measured on a loan by loan basis based on the estimated fair value of the collateral less estimated cost to sell if the loan is considered collateral dependent. Impaired loans not considered to be collateral dependent are measured based on the present value of expected future cash flows. Impairment is measured for each loan in the portfolio except for the smaller groups of homogeneous consumer loans. The categories of non-accrual loans and impaired loans overlap, although they are not coextensive. The Company considers all circumstances regarding the loan and borrower on an individual basis when determining whether an impaired loan should be placed on non-accrual status, such as the financial strength of the borrower, the collateral value, reasons for delay, payment record, the amount of past due and the number of days past due. Loans that experience insignificant payment delays and payment shortfalls are generally not classified as impaired. Management determines the significance of payment delays and payment shortfalls on a case-by-case basis, taking into consideration all of the circumstances surrounding the loan and the borrower, including the length of the delay, the reasons for the delay, the borrower’s prior payment record, and the amount of shortfall in relation to the principal and interest owed.
Allowance for Loan Losses	Allowance for Loan Losses - The allowance for loan losses is maintained at a level considered adequate to provide for probable losses on existing loans based on evaluating known and inherent risks in the loan portfolio. The allowance is reduced by loans charged off and increased by provisions charged to earnings and recoveries on loans previously charged-off. The allowance is based on management’s periodic, systematic evaluation of factors underlying the quality of the loan portfolio including changes in the size and composition of the loan portfolio, the estimated value of any underlying collateral, actual loan loss experience, current economic conditions, and detailed analysis of individual loans for which full collectability may not be assured. This evaluation is inherently subjective as it requires estimates that are susceptible to significant revision as more information becomes available. While management uses the best information available to make its estimates, future adjustments to the allowance may be necessary if there is a significant change in economic and other conditions. The appropriateness of the allowance for loan losses is estimated based on these factors and trends identified by management at the time the financial statements are prepared. When available information confirms that specific loans or portions thereof are uncollectible, these amounts are charged-off against the allowance for loan losses. The existence of some or all of the following criteria will generally confirm that a loss has been incurred: the loan is significantly delinquent and the borrower has not evidenced the ability or intent to bring the loan current; the Company has no recourse to the borrower, or if it does, the borrower has insufficient assets to pay the debt; the estimated fair value of the loan collateral is significantly below the current loan balance, and there is little or no near-term prospect for improvement. A provision of loan losses is charged against income and added to the allowance for loan losses based on regular assessment of the loan portfolio. The allowance for loan losses is allocated to certain loan categories based on the relative risk characteristics, asset classifications, and actual loss experience within the loan portfolio. Although management has allocated the allowance for loan losses to various loan portfolio segments, the allowance is general in nature and is available for the loan portfolio in its entirety. The ultimate recovery of all loans is susceptible to future market factors beyond the Company’s control. These factors may result in losses or recoveries differing significantly from those provided for in the financial statements. In addition, regulatory agencies, as an integral part of their examination process, periodically review the Company’s allowance for loan losses, and may require the Company to make additions to the allowance based on their judgment about information available to them at the time of their examinations.
Reserve for Unfunded Loan Commitments	Reserve for Unfunded Loan Commitments - The reserve for unfunded loan commitments is maintained at a level believed by management to be sufficient to absorb estimated probable losses related to these unfunded credit facilities. The determination of the adequacy of the reserve is based on periodic evaluations of the unfunded credit facilities including an assessment of the probability of commitment usage, credit risk factors for loans outstanding to these same customers, and the terms and expiration dates of the unfunded credit facilities. The reserve for unfunded loan commitments is included in other liabilities on the consolidated balance sheet, with changes to the balance charged against noninterest expense.
Premises and Equipment, Net	Premises and Equipment, Net - Land is carried at cost. Premises and equipment are stated at cost less accumulated depreciation and amortization. Depreciation is computed using the straight-line method over the estimated useful lives of the assets. The estimated useful lives used to compute depreciation include building and building improvements from 25 to 40 years and furniture, fixtures, and equipment from 3 to 10 years. Leasehold and tenant improvements are amortized using the straight-line method over the lesser of useful life or the life of the related lease. Gains or losses on dispositions are reflected in results of operations. Management reviews buildings, improvements and equipment for impairment on an annual basis or whenever events or changes in the circumstances indicate that the undiscounted cash flows for the property are less than its carrying value. If identified, an impairment loss is recognized through a charge to earnings based on the fair value of the property.
Transfers of Financial Assets and Servicing Rights	Transfers of Financial Assets - Transfers of an entire financial asset, a group of entire financial assets, or participating interest in an entire financial asset are accounted for as sales when control over the assets has been surrendered. Control over transferred assets is deemed to be surrendered when (1) the assets have been isolated from the Company, (2) the transferee obtains the right (free of conditions that constrain it from taking advantage of that right) to pledge or exchange the transferred assets, and (3) the Company does not maintain effective control over the transferred assets through an agreement to repurchase them before their maturity. Servicing Rights - Servicing assets are recognized as separate assets when rights are acquired through purchase or through sale of financial assets. Generally, purchased servicing rights are capitalized at the cost to acquire the rights. For sales of mortgage, commercial and consumer loans, a portion of the cost of originating the loan is allocated to the servicing right based on relative fair value. Fair value is based on market prices for comparable mortgage, commercial, or consumer servicing contracts, when available, or alternatively, is based on a valuation model that calculates the present value of estimated future net servicing income. The valuation model incorporates assumptions that market participants would use in estimating future net servicing income, such as the cost to service, the discount rate, the custodial earnings rate, an inflation rate, ancillary income, prepayment speeds, and default rates and losses. Servicing assets are evaluated quarterly for impairment based upon the fair value of the rights as compared to amortized cost. Impairment is determined by stratifying rights into tranches based on predominant characteristics, such as interest rate, loan type, and investor type. Impairment is recognized through a valuation allowance for an individual tranche, to the extent that fair value is less than the capitalized amount for the tranches. If the Company later determines that all or a portion of the impairment no longer exists for a particular tranche, a reduction of the allowance may be recorded as an increase to income. Capitalized servicing rights are stated separately on the Consolidated Balance Sheets and are amortized into noninterest income in proportion to, and over the period of, the estimated future net servicing income of the underlying financial assets.
Income Taxes	Income Taxes - The Company files a consolidated federal income tax return. Deferred federal income taxes result from temporary differences between the tax basis of assets and liabilities, and their reported amounts in the financial statements. These will result in differences between income for tax purposes and income for financial reporting purposes in future years. As changes in tax laws or rates are enacted, deferred tax assets and liabilities are adjusted through the provision for income taxes. Valuation allowances are established to reduce the net recorded amount of deferred tax assets if it is determined to be more likely than not, that all or some portion of the potential deferred tax asset will not be realized. The Company follows the authoritative guidance issued related to accounting for uncertainty in income taxes. The guidance prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. It is the Company’s policy to record any penalties or interest arising from federal or state taxes as a component of income tax expense.
Employee Stock Ownership Plan	Employee Stock Ownership Plan - Compensation expense recognized for the Company’s ESOP equals the fair value of shares that have been allocated or committed to be released for allocation to participants. Any difference between the fair value of the shares at the time and the ESOP’s original acquisition cost is charged or credited to stockholders’ equity (additional paid-in capital). The cost of ESOP shares that have not yet been allocated or committed to be released is deducted from stockholders’ equity.
Earnings Per Share	Earnings Per Share (“EPS”) - Basic EPS are computed by dividing income available to common stockholders by the weighted average number of common shares outstanding for the period. Diluted earnings per share reflect the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock or resulted in the issuance of common stock that then shared in the earnings of the entity. For purposes of computing basic and dilutive EPS, ESOP shares that have been committed to be released are outstanding and ESOP shares that have not been committed to be released shall not be considered outstanding.
Comprehensive Income (Loss)	Comprehensive Income (Loss) - Comprehensive income (loss) is comprised of net income and other comprehensive income (loss). Other comprehensive income (loss) includes items recorded directly to equity, such as unrealized holding gains and losses on securities available-for-sale.
Financial Instruments	Financial Instruments - In the ordinary course of business, the Company has entered into agreements for off-balance-sheet financial instruments consisting of commitments to extend credit and stand-by letters of credit. Such financial instruments are recorded in the financial statements when they are funded or related fees are incurred or received.
Restricted Assets	Restricted Assets – Regulations of the Board of Governors of the Federal Reserve System (“Federal Reserve”) require that the Bank maintain reserves in the form of cash on hand and deposit balances with the FRB, based on a percentage of deposits. The amounts of such balances for the years ended December 31, 2018 and 2017 were $17.4 million and $18.2 million, respectively, included in interest-bearing deposits at other financial institutions on the Consolidated Balance Sheets.
Marketing and Advertising Costs	Marketing and Advertising Costs - The Company records marketing and advertising costs as expenses as they are incurred. Total marketing and advertising expense was $747,000 and $716,000 for the years ended December 31, 2018 and 2017, respectively.
Stock-Based Compensation	Stock-Based Compensation - Compensation cost is recognized for stock options and restricted stock awards, based on the fair value of these awards at the grant date. A Black-Scholes model is utilized to estimate the fair value of stock options, while the market price of the Company’s common stock at the grant date is used for restricted stock awards. Compensation cost is recognized over the required service period, generally defined as the vesting period. For awards with graded vesting, compensation cost is recognized on a straight-line basis over the requisite service period for the entire award.
Goodwill	Goodwill - Goodwill is recorded upon completion of a business combination as the difference between the purchase price and the fair value of net identifiable assets acquired. Goodwill was not recorded until the first quarter of 2016 in recognition of the four retail branches purchased from Bank of America on January 22, 2016. Subsequent to initial recognition, the Company tests goodwill for impairment during the fourth quarter of each fiscal year, or more often if events or circumstances, such as adverse changes in the business climate indicate there may be impairment. There was no goodwill impairment at December 31, 2018 or 2017.
Application of New Accounting Guidance	Application of New Accounting Guidance On January 1, 2018, the Company adopted Financial Accounting Standards Board (“FASB’) Accounting Standards Update (“ASU”) No. 2014‑09, Revenue from Contracts with Customers and all subsequent amendments to the ASU (collectively “ASC 606”) , which created Topic 606 and superseded Topic 605, Revenue Recognition. In August 2015, FASB issued ASU No. 2015‑14, Revenue from Contracts with Customers (Topic 606) , which postponed the effective date of ASU No. 2014‑09. The core principle of Topic 606 is that an entity recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In general, the new guidance requires companies to use more judgment and make more estimates than under past guidance, including identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. For financial reporting purposes, the Company utilized the modified retrospective approach, meaning the ASU is applied only to the most current period presented in the financial statements with the cumulative effect of initially applying the standard recognized at the date of initial application. As a bank holding company, key revenue sources, such as interest income on loans, investment securities and deposits, as well as other sources of income including loan fees, security sales, and derivatives have been identified as out of the scope of this new guidance. Management conducted an assessment of the revenue streams that were affected by the new guidance and identified those considered material and in scope to ensure compliance with the new guidance concluding those related to credit and debit card fees, and service charges and fees on deposit accounts. No additional changes to processes or procedures were identified for the recognition of revenues in scope. The adoption of this ASU did not have a material impact on the Company’s consolidated financial statements. However, additional disclosures required by the ASU have been included in “Note 15 - Revenue from Contracts with Customers” to the Company’s consolidated financial statements. On January 1, 2018, the FASB issued ASU No. 2016‑01, Financial Instruments - Overall (Subtopic 825‑10): Recognition and Measurement of Financial Assets and Financial Liabilities. The new guidance improves the recognition and measurement of financial instruments. This ASU requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes and requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset (i.e., securities or loans and receivables) on the balance sheet or the accompanying notes to the financial statements. Exit price is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. This ASU also eliminates the requirement to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet. The adoption of ASU No. 2016-01 did not have a material impact on the Company’s consolidated financial statements. The disclosures to the Company’s consolidated financial statements have been updated appropriately using the exit price notion in “Note 15 - Fair Value of Financial Instruments.”
RECENT ACCOUNTING PRONOUNCEMENTS	RECENT ACCOUNTING PRONOUNCEMENTS In February 2016, the FASB issued ASU No. 2016‑02, Leases (Topic 842) . ASU No. 2016‑02 requires lessees to recognize on the balance sheet the assets and liabilities arising from operating leases. A lessee should recognize a liability to make lease payments and a right-of-use asset representing its right to use the underlying asset for the lease term. A lessee should include payments to be made in an optional period only if the lessee is reasonably certain to exercise an option to extend the lease or not to exercise an option to terminate the lease. For a finance lease, interest payments should be recognized separately from amortization of the right-of-use asset in the statement of comprehensive income. For operating leases, the lease cost should be allocated over the lease term on a generally straight-line basis. The amendments in ASU 2016‑02 are effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early application of the amendments in the ASU is permitted. In July 2018, the FASB issued ASU No, 2018-10, Codification Improvements to Topic 842, Leases and ASU No. 2018-11, Leases (Topic 842): Targeted Improvements. These ASUs contain clarifications to ASU 2016-02, including providing a new transition method in addition to the existing transition method contained in ASU No. 2016-02 to allow entities to initially apply the new standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. These amendments have the same effective date as ASU 2016-02. The effect of the adoption of these ASUs will depend on leases at time of adoption. The Company expects to adopt the new standard on January 1, 2019 and use the adoption date as the date of initial application. Once adopted, the Company expects to report higher assets and liabilities as a result of including right-of-use assets and lease liabilities related to certain banking offices and certain equipment under noncancelable operating lease agreements. While the Company continues to assess all of the effects of adoption, the Company currently believes the most significant effect will relate to the recognition of new right-of-use assets and lease liabilities on the Consolidated Balance Sheets of approximately $5.0 million at December 31, 2018 based on management’s estimate assuming early adoption. In June 2016, the FASB issued ASU No. 2016‑13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The ASU is intended to improve financial reporting by requiring timelier recording of credit losses on loans and other financial instruments held by financial institutions and other organizations. The ASU requires the measurement of all current expected credit losses (“CECL”) for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. Financial institutions and other organizations will now use forward-looking information to better inform their credit loss estimates. Many of the loss estimation techniques applied today will still be permitted, although the inputs to those techniques will change to reflect the full amount of CECL. Organizations will continue to use judgment to determine which loss estimation method is appropriate for their circumstances. The ASU requires enhanced disclosures to help investors and other financial statement users better understand significant estimates and judgments used in estimating credit losses, as well as the credit quality and underwriting standards of an organization’s portfolio. These disclosures include qualitative and quantitative requirements that provide additional information about the amounts recorded in the financial statements. In addition, the ASU amends the accounting for credit losses on available-for-sale debt securities and purchased financial assets with credit deterioration. The Company is currently evaluating the impact of this ASU on the Company’s consolidated financial statements. This standard requires FDIC-insured institutions and their holding companies (banking organizations) to recognize credit losses expected over the life of certain financial assets. CECL covers a broader range of assets than the current method of recognizing credit losses and generally results in earlier recognition of credit losses. Upon adoption of CECL, a banking organization must record a one-time adjustment to its credit loss allowances as of the beginning of the fiscal year of adoption equal to the difference, if any, between the amount of credit loss allowances under the current methodology and the amount required under CECL. For a banking organization, implementation of CECL is generally likely to reduce retained earnings, and to affect other items, in a manner that reduces its regulatory capital. The ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Early application will be permitted for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. The federal banking regulators (the Federal Reserve, the OCC and the FDIC) have adopted a rule that gives a banking organization the option to phase in over a three-year period the day-one adverse effects of CECL on its regulatory capital. In March 2017, the FASB issued ASU No. 2017‑08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310‑20): Premium Amortization on Purchased Callable Debt Securities . The ASU shortens the amortization period for certain callable debt securities held at a premium. The ASU will take effect for SEC filers for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. The adoption of ASU No. 2017‑08 is not expected to have a material impact on the Company’s consolidated financial statements. In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities . This ASU amends the hedge accounting recognition and presentation requirements in ASC 815 to (1) improve the transparency and understandability of information conveyed to financial statement users about an entity’s risk management activities by better aligning the entity’s financial reporting for hedging relationships with those risk management activities and (2) reduce the complexity of and simplify the application of hedge accounting by preparers. The amendments in this ASU permit hedge accounting for hedging relationships involving nonfinancial risk and interest rate risk by removing certain limitations in cash flow and fair value hedging relationships. In addition, the ASU requires an entity to present the earnings effect of the hedging instrument in the same income statement line item in which the earnings effect of the hedged item is reported. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2018 and early adoption is permitted. The adoption of ASU No. 2017-12 is not expected to have a material impact on the Company's consolidated financial statements. In March 2018, the FASB issued ASU No. 2018-05, Income Taxes (Topic 740) . This ASU was issued to provide guidance on the income tax accounting implications of the Tax Cuts and Jobs Act (“Tax Act”) and allows for entities to report provisional amounts for specific income tax effects of the Tax Act for which the accounting under Topic 740 was not yet complete but a reasonable estimate could be determined. A measurement period of one year is allowed to complete the accounting effects under Topic 740 and revise any previous estimates reported. Any provisional amounts or subsequent adjustments included in an entity’s financial statements during the measurement period should be included in income from continuing operations as an adjustment to tax expense in the reporting period the amounts are determined. The Company adopted this ASU with the provisional adjustments as reported in the Consolidated Financial Statements on Form 10-K as of December 31, 2017. As of December 31, 2018, the Company did not incur any adjustments to the provisional recognition. In June 2018, the FASB issued ASU No. 2018-07, Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting . This ASU was issued to expand the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. Previously, these awards were recorded at the fair value of consideration received or the fair value of the equity instruments issued and was measured as the earlier of the commitment date or date performance was completed. The amendments in this ASU require the awards to be measured at the grant-date fair value of the equity instrument. ASU No. 2018-07 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. Early adoption is permitted, but no earlier than an entity's adoption of Topic 606. The adoption of ASU No. 2018-07 is not expected to have a material impact on the Company's consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement. This ASU contains some technical adjustments related to the fair value disclosure requirements of public companies. Included in this ASU is the additional disclosure requirement of unrealized gains and losses for the period in recurring level 3 fair value disclosures and the range and weighted average of significant unobservable inputs, among other technical changes. ASU 2018-13 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Early adoption is permitted for any removed or modified disclosures. The adoption of ASU 2018-13 is not expected to have a material impact on the Company's consolidated financial statements. In August 2018, FASB issued ASU No. 2018-15, Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract. The amendments in this ASU broaden the scope of ASC Subtopic 350-40 to include costs incurred to implement a hosting arrangement that is a service contract. The amendments align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). The costs are capitalized or expensed depending on the nature of the costs and the project stage during which they are incurred, consistent with the accounting for costs for internal-use software. The amendments in this ASU result in consistent capitalization of implementation costs of a hosting arrangement that is a service contract and implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). The accounting for the service element of a hosting arrangement that is a service contract is not affected by the amendments in this ASU. This ASU is effective for fiscal years beginning after December 15, 2019 and interim periods within those fiscal years. The amendments in this ASU should be applied either retrospectively to all implementation costs incurred after the date of adoption. Adoption of ASU 2018-15 is not expected to have a material impact on the Company’s consolidated financial statements. In October 2018, FASB issued ASU No. 2018-16, Derivatives and Hedging (Topic 815), Inclusion of the Secured Overnight Financing Rate (“SOFR”) Overnight Index Swap (“OIS”) Rate as a Benchmark Interest Rate for Hedge Accounting. In the United States, eligible benchmark interest rates under Topic 815 are interest rates on direct Treasury obligations of the U.S. government, the London Interbank Offered Rate (“LIBOR”) swap rate, and the OSI Rate based on the Fed Funds Effective Rate. ASU 2018-16 adds the OIS Rate based on SOFR as a U.S. benchmark interest rate to facilitate the LIBOR to SOFR transition and provide sufficient lead time for entities to prepare for changes to interest rate hedging strategies for both risk management and hedge accounting purposes. The adoption of this ASU is not expected to have a material impact on the Company’s consolidated financial statements.
401 (k) Plan	401(k) Plan The Company has a salary deferral 401(k) Plan covering substantially all of its employees. Employees are eligible to participate in the 401(k) plan at the date of hire if they are 18 years of age. Eligible employees may contribute through payroll deductions and are 100% vested at all times in their deferral contributions account. The Company matches 100% for contributions of 1% to 3%, and 50% for contributions of 4% to 5%. There was a $917,000 and $904,000 matching contribution for the years ended December 31, 2018 and 2017, respectively.

Business Combination (Tables)

Business Combination (Tables)	12 Months Ended
	Dec. 31, 2018
Business Combination [Abstract]
Schedule of Estimated Fair Values of Assets Acquired and Liabilities Assumed at Acquisition	The following table summarizes the estimated fair values of assets acquired and liabilities assumed at the date of acquisition: Acquired Book Fair Value Amount November 15, 2018 Value Adjustments Recorded Assets Cash and cash equivalents $ 54,558 $ — $ 54,558 Securities available-for-sale 19,609 (54) 19,555 Loans receivable, net 361,596 (5,321) (1) 356,275 Premises and equipment, net 8,411 3,354 (2) 11,765 Other real estate owned 689 — 689 Deferred tax asset 4,097 (3,358) 739 Mortgage servicing rights 218 564 782 Core deposit intangible (“CDI”) — 5,251 (3) 5,251 Other assets 25,231 18 25,249 Total assets acquired $ 474,409 $ 454 $ 474,863 Liabilities Deposits $ 357,863 $ (1,052) (4) $ 356,811 Borrowings 37,000 (282) 36,718 Other liabilities 9,286 63 9,349 Total liabilities assumed $ 404,149 $ (1,271) $ 402,878
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	The following table summarizes the consideration paid, the aggregate amount recognized for each major class of assets acquired and liabilities assumed by 1st Security Bank in the Anchor Acquisition: At November 15, 2018 Purchase price of Anchor Fair value of FS Bancorp common stock at $46.54 (1) per share for 725,518 shares $ Cash paid Total purchase price Fair value of assets acquired: Cash and cash equivalents $ 54,558 Securities available-for-sale 19,555 Loans receivable, net 356,275 Premises and equipment 11,765 OREO 689 Deferred tax asset 739 Mortgage servicing rights 782 Intangible assets - CDI 5,251 Other assets 25,249 Total assets and identifiable intangible assets acquired $ 474,863 Fair value of liabilities assumed: Deposits $ 356,811 Borrowings 36,718 Other liabilities 9,349 Total liabilities assumed $ 402,878 Fair value of net assets and identifiable intangible assets acquired Bargain purchase gain $ _________________________ (1) Stock price is as of the closing date.

Securities Available-for-sale (

Securities Available-for-sale (Tables)	12 Months Ended
	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Schedule of Available-for-sale Securities Reconciliation	The following tables present the amortized costs, unrealized gains, unrealized losses, and estimated fair values of securities available-for-sale at December 31, 2018 and 2017: December 31, 2018 Estimated Amortized Unrealized Unrealized Fair Cost Gains Losses Values SECURITIES AVAILABLE-FOR-SALE U.S. agency securities $ 16,052 $ 32 $ (197) $ 15,887 Corporate securities 7,074 — (209) 6,865 Municipal bonds 14,446 23 (275) 14,194 Mortgage-backed securities 45,827 83 (1,074) 44,836 U.S. Small Business Administration securities 15,690 — (267) 15,423 Total securities available-for-sale $ 99,089 $ 138 $ (2,022) $ 97,205 December 31, 2017 Estimated Amortized Unrealized Unrealized Fair Cost Gains Losses Values SECURITIES AVAILABLE-FOR-SALE U.S. agency securities $ 9,077 $ 49 $ (11) $ 9,115 Corporate securities 7,113 9 (96) 7,026 Municipal bonds 12,720 148 (82) 12,786 Mortgage-backed securities 40,161 63 (490) 39,734 U.S. Small Business Administration securities 14,014 — (195) 13,819 Total securities available-for-sale $ 83,085 $ 269 $ (874) $ 82,480
Schedule of Unrealized Loss on Investments	Investment securities that were in an unrealized loss position at December 31, 2018 and 2017 are presented in the following tables, based on the length of time individual securities have been in an unrealized loss position. Management believes that these securities are only temporarily impaired due to changes in market interest rates or the widening of market spreads subsequent to the initial purchase of the securities, and not due to concerns regarding the underlying credit of the issuers or the underlying collateral. December 31, 2018 Less than 12 Months 12 Months or Longer Total Fair Unrealized Fair Unrealized Fair Unrealized Value Losses Value Losses Value Losses SECURITIES AVAILABLE-FOR-SALE U.S. agency securities $ 6,018 $ (25) $ 4,822 $ (172) $ 10,840 $ (197) Corporate securities 975 (25) 5,890 (184) 6,865 (209) Municipal bonds 2,098 (22) 8,787 (253) 10,885 (275) Mortgage-backed securities 6,266 (40) 32,537 (1,034) 38,803 (1,074) U.S. Small Business Administration securities 1,958 (11) 13,465 (256) 15,423 (267) Total $ 17,315 $ (123) $ 65,501 $ (1,899) $ 82,816 $ (2,022) December 31, 2017 Less than 12 Months 12 Months or Longer Total Fair Unrealized Fair Unrealized Fair Unrealized Value Losses Value Losses Value Losses SECURITIES AVAILABLE-FOR-SALE U.S. agency securities $ 2,987 $ (11) $ — $ — $ 2,987 $ (11) Corporate securities 4,102 (15) 1,915 (81) 6,017 (96) Municipal bonds 5,982 (82) — — 5,982 (82) Mortgage-backed securities 7,262 (61) 20,635 (429) 27,897 (490) U.S. Small Business Administration securities 11,876 (162) 1,943 (33) 13,819 (195) Total $ 32,209 $ (331) $ 24,493 $ (543) $ 56,702 $ (874)
Schedule of Available for Sale Securities by Contractual Maturity	The contractual maturities of securities available-for-sale at December 31, 2018 and 2017 are listed below. Expected maturities of mortgage-backed securities may differ from contractual maturities because borrowers may have the right to call or prepay the obligations; therefore, these securities are classified separately with no specific maturity date. December 31, 2018 December 31, 2017 Amortized Fair Amortized Fair Cost Value Cost Value U.S. agency securities Due after one year through five years $ 1,043 $ 1,040 $ — $ — Due after five years through ten years 10,011 9,941 4,079 4,124 Due after ten years 4,998 4,906 4,998 4,991 Subtotal 16,052 15,887 9,077 9,115 Corporate securities Due after one year through five years 6,077 5,947 5,117 5,111 Due after five years through ten years 997 918 1,996 1,915 Subtotal 7,074 6,865 7,113 7,026 Municipal bonds Due after one year through five years 2,659 2,570 2,001 2,026 Due after five years through ten years 2,610 2,592 4,111 4,206 Due after ten years 9,177 9,032 6,608 6,554 Subtotal 14,446 14,194 12,720 12,786 Mortgage-backed securities Federal National Mortgage Association (“FNMA”) 30,554 30,026 23,310 23,091 Federal Home Loan Mortgage Corporation (“FHLMC”) 10,301 9,961 10,818 10,629 Government National Mortgage Association (“GNMA”) 4,972 4,849 6,033 6,014 Subtotal 45,827 44,836 40,161 39,734 U.S. Small Business Administration securities Due after five years through ten years 13,828 13,581 12,065 11,896 Due after ten years 1,862 1,842 1,949 1,923 Subtotal 15,690 15,423 14,014 13,819 Total $ 99,089 $ 97,205 $ 83,085 $ 82,480
Schedule of Realized Gain (Loss)	The proceeds and resulting gains and losses, computed using specific identification from sales of securities available-for-sale for the years ended December 31, 2018 and 2017 were as follows: December 31, 2018 Proceeds Gross Gains Gross Losses Securities available-for-sale $ 24,312 $ 185 $ (14) December 31, 2017 Proceeds Gross Gains Gross Losses Securities available-for-sale $ 39,103 $ 413 $ (33)

Loans Receivable and Allowanc_2

Loans Receivable and Allowance For Loan Losses (Tables)	12 Months Ended
	Dec. 31, 2018
Receivables [Abstract]
Schedule of Accounts, Notes, Loans and Financing Receivable	The composition of the loan portfolio was as follows at December 31: December 31, December 31, 2018 2017 REAL ESTATE LOANS Commercial $ 204,699 $ 63,611 Construction and development 247,306 143,068 Home equity 40,258 25,289 One-to-four-family (excludes loans held for sale) 249,397 163,655 Multi-family 104,663 44,451 Total real estate loans 846,323 440,074 CONSUMER LOANS Indirect home improvement 167,793 130,176 Solar 44,433 41,049 Marine 57,822 35,397 Other consumer 5,425 2,046 Total consumer loans 275,473 208,668 COMMERCIAL BUSINESS LOANS Commercial and industrial 138,686 83,306 Warehouse lending 65,756 41,397 Total commercial business loans 204,442 124,703 Total loans receivable, gross 1,326,238 773,445 Allowance for loan losses (12,349) (10,756) Deferred costs and fees, net (2,907) (2,708) Premiums on purchased loans 1,537 1,577 Total loans receivable, net $ 1,312,519 $ 761,558
Allowance for Credit Losses on Financing Receivables	The following tables detail activities in the allowance for loan losses by loan categories for the years shown: At or For the Year Ended December 31, 2018 Commercial Real Estate Consumer Business Unallocated Total ALLOWANCE FOR LOAN LOSSES Beginning balance $ 4,770 $ 2,814 $ 2,014 $ 1,158 $ 10,756 Provision for loan losses 953 526 1,173 (1,112) 1,540 Charge-offs (4) (936) — — (940) Recoveries 42 947 4 — 993 Net recoveries 38 11 4 — 53 Ending balance $ 5,761 $ 3,351 $ 3,191 $ 46 $ 12,349 Period end amount allocated to: Loans individually evaluated for impairment $ 125 $ 150 $ 700 $ — $ 975 Loans collectively evaluated for impairment 5,636 3,201 2,491 46 11,374 Ending balance $ 5,761 $ 3,351 $ 3,191 $ 46 $ 12,349 LOANS RECEIVABLE Loans individually evaluated for impairment $ 834 $ 428 $ 1,685 $ — $ 2,947 Loans collectively evaluated for impairment 845,489 275,045 202,757 — 1,323,291 Ending balance $ 846,323 $ 275,473 $ 204,442 $ — $ 1,326,238 At or For the Year Ended December 31, 2017 Commercial Real Estate Consumer Business Unallocated Total ALLOWANCE FOR LOAN LOSSES Beginning balance $ 3,547 $ 2,082 $ 2,675 $ 1,907 $ 10,211 Provision for loan losses 1,253 884 (638) (749) 750 Charge-offs (65) (832) (33) — (930) Recoveries 35 680 10 — 725 Net charge-offs (30) (152) (23) — (205) Ending balance $ 4,770 $ 2,814 $ 2,014 $ 1,158 $ 10,756 Period end amount allocated to: Loans individually evaluated for impairment $ 21 $ 68 $ — $ — $ 89 Loans collectively evaluated for impairment 4,749 2,746 2,014 1,158 10,667 Ending balance $ 4,770 $ 2,814 $ 2,014 $ 1,158 $ 10,756 LOANS RECEIVABLE Loans individually evaluated for impairment $ 348 $ 195 $ 551 $ — $ 1,094 Loans collectively evaluated for impairment 439,726 208,473 124,152 — 772,351 Ending balance $ 440,074 $ 208,668 $ 124,703 $ — $ 773,445
Past Due Financing Receivables	The following tables provide information pertaining to the aging analysis of contractually past due loans and non-accrual loans for the years ended December 31, 2018 and 2017: December 31, 2018 30-59 60-89 Days Days 90 Days Total Total Past Past or More Past Loans Non- Due Due Past Due Due Current Receivable Accrual REAL ESTATE LOANS Commercial $ — $ — $ — $ — $ 204,699 $ 204,699 $ — Construction and development — — — — 247,306 247,306 — Home equity 158 40 229 427 39,831 40,258 229 One-to-four-family 1,274 164 1,358 2,796 246,601 249,397 1,552 Multi-family — — — — 104,663 104,663 — Total real estate loans 1,432 204 1,587 3,223 843,100 846,323 1,781 CONSUMER LOANS Indirect home improvement 438 196 113 747 167,046 167,793 367 Solar 62 43 41 146 44,287 44,433 41 Marine 50 — — 50 57,772 57,822 18 Other consumer 69 24 11 104 5,321 5,425 2 Total consumer loans 619 263 165 1,047 274,426 275,473 428 COMMERCIAL BUSINESS LOANS Commercial and industrial — 431 — 431 138,255 138,686 1,685 Warehouse lending — — — — 65,756 65,756 — Total commercial business loans — 431 — 431 204,011 204,442 1,685 Total loans $ 2,051 $ 898 $ 1,752 $ 4,701 $ 1,321,537 $ 1,326,238 $ 3,894 December 31, 2017 30-59 60-89 Days Days 90 Days Total Total Past Past or More Past Loans Non- Due Due Past Due Due Current Receivable Accrual REAL ESTATE LOANS Commercial $ — $ — $ — $ — $ 63,611 $ 63,611 $ — Construction and development — — — — 143,068 143,068 — Home equity 122 — 136 258 25,031 25,289 151 One-to-four-family 142 — — 142 163,513 163,655 142 Multi-family — — — — 44,451 44,451 — Total real estate loans 264 — 136 400 439,674 440,074 293 CONSUMER LOANS Indirect home improvement 255 215 99 569 129,607 130,176 195 Solar 49 19 — 68 40,981 41,049 — Marine — — — — 35,397 35,397 — Other consumer — — — — 2,046 2,046 — Total consumer loans 304 234 99 637 208,031 208,668 195 COMMERCIAL BUSINESS LOANS Commercial and industrial — 551 — 551 82,755 83,306 551 Warehouse lending — — — — 41,397 41,397 — Total commercial business loans — 551 — 551 124,152 124,703 551 Total loans $ 568 $ 785 $ 235 $ 1,588 $ 771,857 $ 773,445 $ 1,039
Impaired Financing Receivables	The following tables provide additional information about our impaired loans that have been segregated to reflect loans for which an allowance for credit losses has been provided and loans for which no allowance was provided for the years ended December 31, 2018 and 2017: December 31, 2018 Unpaid Principal Recorded Related Balance Impairment Investment Allowance WITH NO RELATED ALLOWANCE RECORDED Home equity $ 229 $ — $ 229 $ — WITH RELATED ALLOWANCE RECORDED One-to-four-family 1,552 — 1,552 125 Consumer loans 428 — 428 150 Commercial business loans 1,685 — 1,685 700 3,665 — 3,665 975 Total $ 3,894 $ — $ 3,894 $ 975 December 31, 2017 Unpaid Principal Recorded Related Balance Impairment Investment Allowance WITH NO RELATED ALLOWANCE RECORDED Home equity $ 151 $ — $ 151 $ — One-to-four-family 67 (12) 55 — Total real estate loans 218 (12) 206 — Commercial business loans 551 — 551 — 769 (12) 757 — WITH RELATED ALLOWANCE RECORDED One-to-four-family 142 — 142 21 Consumer loans 195 — 195 68 337 — 337 89 Total $ 1,106 $ (12) $ 1,094 $ 89 The following table presents the average recorded investment in loans individually evaluated for impairment and the interest income recognized and received for the years ended December 31, 2018 and 2017: At or For the Year Ended December 31, 2018 December 31, 2017 Average Recorded Interest Income Average Recorded Interest Income Investment Recognized Investment Recognized WITH NO RELATED ALLOWANCE RECORDED Home equity $ 404 $ 8 $ 219 $ — One-to-four-family 719 — 56 3 Total real estate loans 1,123 8 275 3 Commercial business loans — — 551 24 1,123 8 826 27 WITH RELATED ALLOWANCE RECORDED One-to-four-family 1,030 28 142 (1) 4 Consumer loans 338 37 281 16 Commercial business loans 1,188 81 — — 2,556 146 423 20 Total $ 3,679 $ 154 $ 1,249 $ 47 __________________________ (1) Includes loans supported by Federal Housing Administration (“FHA”) guarantees.
Financing Receivable Credit Quality Indicators	The following tables summarize risk rated loan balances by category at the dates indicated: December 31, 2018 Special Pass Watch Mention Substandard Doubtful Loss (1 - 5) (6) (7) (8) (9) (10) Total REAL ESTATE LOANS Commercial $ 203,557 $ 1,142 $ — $ — $ — $ — $ 204,699 Construction and development 244,577 2,729 — — — — 247,306 Home equity 39,846 — 183 229 — — 40,258 One-to-four-family 247,575 207 63 1,552 — — 249,397 Multi-family 103,447 1,216 — — — — 104,663 Total real estate loans 839,002 5,294 246 1,781 — — 846,323 CONSUMER LOANS Indirect home improvement 167,426 — — 367 — — 167,793 Solar 44,392 — — 41 — — 44,433 Marine 57,804 — — 18 — — 57,822 Other consumer 5,415 — 8 2 — — 5,425 Total consumer loans 275,037 — 8 428 — — 275,473 COMMERCIAL BUSINESS LOANS Commercial and industrial 124,089 8,813 — 5,784 — — 138,686 Warehouse lending 65,756 — — — — — 65,756 Total commercial business loans 189,845 8,813 — 5,784 — — 204,442 Total loans receivable, gross $ 1,303,884 $ 14,107 $ 254 $ 7,993 $ — $ — $ 1,326,238 December 31, 2017 Special Pass Watch Mention Substandard Doubtful Loss (1 - 5) (6) (7) (8) (9) (10) Total REAL ESTATE LOANS Commercial $ 62,057 $ — $ 1,554 $ — $ — $ — $ 63,611 Construction and development 143,068 — — — — — 143,068 Home equity 25,138 — — 151 — — 25,289 One-to-four-family 163,513 — — 142 — — 163,655 Multi-family 44,451 — — — — — 44,451 Total real estate loans 438,227 — 1,554 293 — — 440,074 CONSUMER LOANS Indirect home improvement 129,981 — — 195 — — 130,176 Solar 41,049 — — — — — 41,049 Marine 35,397 — — — — — 35,397 Other consumer 1,998 — — 48 — — 2,046 Total consumer loans 208,425 — — 243 — — 208,668 COMMERCIAL BUSINESS LOANS Commercial and industrial 76,942 — 425 5,939 — — 83,306 Warehouse lending 40,724 673 — — — — 41,397 Total commercial business loans 117,666 673 425 5,939 — — 124,703 Total loans receivable, gross $ 764,318 $ 673 $ 1,979 $ 6,475 $ — $ — $ 773,445
Schedule of Related Party Loans	Outstanding loan balances were as follows and were within regulatory limitations: At December 31, 2018 2017 Beginning balance $ 655 $ 313 Additions 2,688 351 Repayments (18) (9) Ending balance $ 3,325 $ 655

Servicing Rights (Tables)

Servicing Rights (Tables)	12 Months Ended
	Dec. 31, 2018
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Schedule of Fair Value, Off-balance Sheet Risks [Table Text Block]	The following table summarizes servicing rights activity for the years ended December 31, 2018 and 2017: 2018 2017 Beginning balance $ 6,795 $ 8,459 Additions 5,971 5,075 Sales — (4,751) Servicing rights amortized (2,337) (1,988) Ending balance $ 10,429 $ 6,795
Valuation assumptions used in determining the fair value of servicing rights	Shown in the table below is the fair value of financial instruments measured under a Level 3 unobservable input on a recurring and nonrecurring basis at December 31, 2018: Level 3 Significant Range Weighted Fair Value Instruments Valuation Technique Unobservable Inputs (Weighted Average) Average RECURRING Interest rate lock commitments with customers Quoted market prices Pull-through expectations 80% - 99% 95.2 % Individual forward sale commitments with investors Quoted market prices Pull-through expectations 80% - 99% 95.2 % NONRECURRING Impaired loans Fair value of underlying collateral Discount applied to the obtained appraisal 0% - 50% 25.0 % OREO Fair value of collateral Discount applied to the obtained appraisal 0% - 75% 71.1 %
Key economic assumptions and the sensitivity of the current fair value for single family mortgage servicing rights	Key economic assumptions and the sensitivity of the current fair value for single family MSR to immediate adverse changes in those assumptions at December 31, 2018 and December 31, 2017 were as follows: December 31, 2018 December 31, 2017 Aggregate portfolio principal balance $ 1,186,858 $ 775,093 Weighted average rate of note 4.3 % % At December 31, 2018 Base 0.5% Adverse Rate Change 1.0% Adverse Rate Change Conditional prepayment rate 8.8 % 11.6 % 17.7 % Fair value MSR $ 14,218 $ 12,723 $ 10,358 Percentage of MSR 1.2 % 1.1 % 0.9 % Discount rate 9.6 % 10.1 % 10.6 % Fair value MSR $ 14,218 $ 13,912 $ 13,617 Percentage of MSR 1.2 % 1.2 % 1.2 % At December 31, 2017 Base 0.5% Adverse Rate Change 1.0% Adverse Rate Change Conditional prepayment rate 10.9 % 17.7 % 24.5 % Fair value MSR $ 8,602 $ 6,811 $ 5,614 Percentage of MSR 1.1 % 0.9 % 0.7 % Discount rate 9.6 % 10.1 % 10.6 % Fair value MSR $ 8,602 $ 8,433 $ 8,271 Percentage of MSR 1.1 % 1.1 % 1.1 %
Mortgage servicing rights
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Valuation assumptions used in determining the fair value of servicing rights	The following provides valuation assumptions used in determining the fair value of MSR at the dates indicated: At December 31, 2018 2017 Key assumptions: Weighted average discount rate 9.5 % 9.5 % Conditional prepayment rate (“CPR”) 9.4 % 10.9 % Weighted average life in years 7.7 6.7

Premises and Equipment (Tables)

Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Schedule of Premises and Equipment	Premises and equipment at December 31, 2018 and 2017 were as follows: 2018 2017 Land $ 5,227 $ 2,028 Buildings 16,772 8,611 Furniture, fixtures, and equipment 12,039 10,105 Leasehold improvements 2,422 2,108 Building improvements 5,897 4,545 Projects in process 674 189 Subtotal 43,031 27,586 Less accumulated depreciation and amortization (13,921) (12,128) Total $ 29,110 $ 15,458
Schedule of Future Minimum Rental Payments for Operating Leases	Minimum net rental commitments under non-cancelable leases, having an original or remaining term of more than one year for future years, were as follows: Years Ending December 31, 2019 $ 1,312 2020 1,005 2021 855 2022 749 2023 390 Thereafter 1,228 Total $ 5,539

Other Real Estate Owned (Tables

Other Real Estate Owned (Tables)	12 Months Ended
	Dec. 31, 2018
Banking and Thrift [Abstract]
Schedule of Other Real Estate Owned	The following table presents the activity related to OREO at and for the years ended December 31: At or For the Year Ended December 31, 2018 2017 Beginning balance $ — $ — Additions 689 — Ending balance $ 689 $ —

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2018
Banking and Thrift [Abstract]
Schedule of Deposit Liabilities	Deposits are summarized as follows at December 31: December 31, December 31, 2018 (1)(2) 2017 (1) Noninterest-bearing checking $ 221,107 $ 177,739 Interest-bearing checking 151,103 119,872 Savings 122,344 72,082 Money market (3) 282,595 228,742 Certificates of deposit less than $100,000 (4) 243,193 111,489 Certificates of deposit of $100,000 through $250,000 154,095 77,934 Certificates of deposit of $250,000 and over (5) 86,357 32,833 Escrow accounts related to mortgages serviced 13,425 9,151 Total $ 1,274,219 $ 829,842 ________________________ (1) Includes $120.0 million and $134.6 million of deposits at December 31, 2018 and 2017, respectively, remaining from the January 22, 2016 purchase of four retail bank branches from Bank of America, N.A. (the “Branch Purchase”). (2) On November 15, 2018, the Company completed the Anchor Acquisition and acquired approximately $357.9 million in deposits. (3) Includes $1,000 of brokered deposits at December 31, 2018 and $6.5 million at December 31, 2017. (4) Includes $116.7 million and $59.3 million of brokered deposits at December 31, 2018 and 2017, respectively. (5) Time deposits that meet or exceed the FDIC insurance limit.
Schedule of Maturities of Time Deposits for Future Periods	Scheduled maturities of time deposits at December 31, 2018 for future years ending are as follows: At December 31, 2018 Maturing in 2019 $ 290,822 Maturing in 2020 117,077 Maturing in 2021 37,277 Maturing in 2022 29,472 Maturing in 2023 8,997 Thereafter — Total $ 483,645
Schedule of Interest Expense by Deposit Category	Interest expense by deposit category for the years ended December 31, 2018 and 2017 is as follows: 2018 2017 Interest-bearing checking $ 227 $ 128 Savings and money market 2,054 1,260 Certificates of deposit 5,040 2,532 Total $ 7,321 $ 3,920

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Schedule of Advances on Borrowing Line	Advances on these lines at December 31, 2018 and 2017 were as follows: 2018 2017 Federal Home Loan Bank - (interest rates ranging from 1.15% to 2.87% and 0.96% to 1.73% at December 31, 2018 and 2017, respectively) $ 137,149 $ 7,529 Total $ 137,149 $ 7,529
Debt with Maximum and Average Balances	The maximum and average outstanding and weighted average interest rates on debt during the years ended December 31, 2018 and 2017 were as follows: 2018 2017 Maximum balance: Federal Home Loan Bank advances and Fed Funds $ 180,025 $ 70,419 Federal Reserve Bank $ — $ 1,000 Fed Funds lines of credit $ 21,016 $ 17,501 Subordinated note $ 10,000 $ 10,000 Average balance: Federal Home Loan Bank advances and Fed Funds $ 96,044 $ 25,635 Federal Reserve Bank $ 5,286 $ 3 Fed Funds lines of credit $ — $ 876 Subordinated note $ 10,000 $ 10,000 Weighted average interest rate: Federal Home Loan Bank advances and Fed Funds 2.02 % 1.26 % Federal Reserve Bank — % 1.75 % Fed Funds lines of credit 1.93 % 1.30 % Subordinated note 6.50 % 6.50 %
Schedule of Federal Home Loan Bank Advances Maturities Summary Due	Scheduled maturities of Federal Home Loan Bank advances were as follows: Interest Year Ending December 31, Balances Rates 2019 $ 121,233 2.36 % 2020 12,284 2.46 % 2021 — — % 2022 — — % 2023 3,632 2.87 % Total $ 137,149

Employee Benefits (Tables)

Employee Benefits (Tables)	12 Months Ended
	Dec. 31, 2018
Compensation and Retirement Disclosure [Abstract]
Schedule of Shares Under ESOP	Shares held by the ESOP at December 31, 2018 and December 31, 2017, were as follows (shown as actual): Balances Balances at December 31, 2018 at December 31, 2017 Allocated shares 176,809 153,049 Committed to be released shares — — Unallocated shares 77,763 103,684 Total ESOP shares 254,572 256,733 Fair value of unallocated shares (in thousands) $ 3,627 $ 5,696

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
INCOME TAXES
Schedule of Components of Income Tax Expense (Benefit)	The components of income tax expense for the years ended December 31, 2018 and 2017, were as follows: 2018 2017 Provision for income taxes Current $ 3,455 $ 7,212 Deferred 768 (718) Total provision for income taxes $ 4,223 $ 6,494
Schedule of Effective Income Tax Rate Reconciliation	A reconciliation of the effective income tax rate with the federal statutory tax rates at December 31, 2018 and 2017 was as follows: 2018 2017 Amount Rate Amount Rate Income tax provision at statutory rate $ 6,000 21.0 % $ 7,203 35.0 % Tax exempt income (129) (0.5) (218) (1.0) Nondeductible items resulting in increase in tax 279 1.0 — — Decrease in tax resulting from other items (87) (0.3) (487) (2.4) Equity compensation (571) (2.0) — — Executive compensation 135 0.5 — — Bargain purchase gain (1,594) (5.6) — — Income tax rate differential — — (396) (1.9) ESOP 190 0.7 392 1.9 Total $ 4,223 14.8 % $ 6,494 31.6 %
Schedule of Deferred Tax Assets and Liabilities	Total deferred tax assets and liabilities at December 31, 2018 and 2017 were as follows: 2018 2017 Deferred Tax Assets Net operating loss carryforward $ 1,201 $ — Allowance for loan losses 3,077 1,912 Other real estate owned 127 — Non-accrued loan interest 115 9 Restricted stock awards 54 — Non-qualified stock options 71 — Securities available-for-sale 405 130 Other 473 210 Total deferred tax assets 5,523 2,261 Deferred Tax Liabilities Loan origination costs (626) (870) Servicing rights (2,241) (1,461) Prepaids (166) (52) Stock dividend - FHLB stock (73) (1) Property, plant, and equipment (1,489) (484) Acquisition related costs (1,289) — Total deferred tax liabilities (5,884) (2,868) Net deferred tax liabilities $ (361) $ (607)

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of Commitments to Extend Credit	The following table provides a summary of the Company’s commitments at December 31, 2018 and 2017: 2018 2017 COMMITMENTS TO EXTEND CREDIT REAL ESTATE LOANS Commercial $ 5,836 $ 107 Construction and development 76,889 73,321 One-to-four-family (includes locks for salable loans) 35,714 37,336 Home equity 41,204 32,889 Multi-family 515 438 Total real estate loans 160,158 144,091 CONSUMER LOANS 18,560 10,041 COMMERCIAL BUSINESS LOANS Commercial and industrial 72,880 52,452 Warehouse lending 44,243 78,303 Total commercial business loans 117,123 130,755 Total commitments to extend credit $ 295,841 $ 284,887

Regulatory Capital (Tables)

Regulatory Capital (Tables)	12 Months Ended
	Dec. 31, 2018
Regulatory Capital Requirements [Abstract]
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations	The following table compares the Bank’s actual capital amounts and ratios at December 31, 2018 and 2017 to their minimum regulatory capital requirements and well capitalized regulatory capital at those dates (dollars in thousands): To be Well Capitalized Under Prompt For Capital For Capital Adequacy Corrective Actual Adequacy Purposes with Capital Buffer Action Provisions Bank Only Amount Ratio Amount Ratio Amount Ratio Amount Ratio At December 31, 2018 Total risk-based capital (to risk-weighted assets) $ 188,472 13.52 % $ 111,493 8.00 % $ 137,694 9.88 % $ 139,366 10.00 % Tier 1 risk-based capital (to risk-weighted assets) $ 175,824 12.62 % $ 83,620 6.00 % $ 109,820 7.88 % $ 111,493 8.00 % Tier 1 leverage capital (to average assets) $ 175,824 10.67 % $ 65,884 4.00 % $ — N/A $ 82,355 5.00 % CET 1 capital (to risk-weighted assets) $ 175,824 12.62 % $ 62,715 4.50 % $ 88,846 6.38 % $ 90,588 6.50 % At December 31, 2017 Total risk-based capital (to risk-weighted assets) $ 133,967 16.25 % $ 65,965 8.00 % $ 76,272 9.25 % $ 82,456 10.00 % Tier 1 risk-based capital (to risk-weighted assets) $ 123,651 15.00 % $ 49,474 6.00 % $ 59,781 7.25 % $ 65,965 8.00 % Tier 1 leverage capital (to average assets) $ 123,651 12.61 % $ 39,233 4.00 % $ — N/A $ 49,041 5.00 % CET 1 capital (to risk-weighted assets) $ 123,651 15.00 % $ 37,105 4.50 % $ 47,412 5.75 % $ 53,597 6.50 %

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Schedule Of Available For Sale Securities Measured At Fair Value On A Recurring Basis	The following tables present securities available-for-sale measured at fair value on a recurring basis at the dates indicated: Securities Available-for-Sale Level 1 Level 2 Level 3 Total At December 31, 2018 U.S. agency securities $ — $ 15,887 $ — $ 15,887 Corporate securities — 6,865 — 6,865 Municipal bonds — 14,194 — 14,194 Mortgage-backed securities — 44,836 — 44,836 U.S. Small Business Administration securities — 15,423 — 15,423 Total $ — $ 97,205 $ — $ 97,205 Securities Available-for-Sale Level 1 Level 2 Level 3 Total At December 31, 2017 U.S. agency securities $ — $ 9,115 $ — $ 9,115 Corporate securities — 7,026 — 7,026 Municipal bonds — 12,786 — 12,786 Mortgage-backed securities — 39,734 — 39,734 U.S. Small Business Administration securities — 13,819 — 13,819 Total $ — $ 82,480 $ — $ 82,480
Fair Value, Mortgage Loans Held for Sale	The following table presents mortgage loans held for sale measured at fair value on a recurring basis at the dates indicated: Mortgage Loans Held for Sale Level 1 Level 2 Level 3 Total December 31, 2018 $ — $ 51,195 $ — $ 51,195 December 31, 2017 $ — $ 53,463 $ — $ 53,463
Schedule of Commitments at Fair Value on Recurring Basis	The following tables present the fair value of interest rate lock commitments with customers, individual forward sale commitments with investors, and paired off commitments with investors measured at their fair value on a recurring basis at the dates indicated: Interest Rate Lock Commitments with Customers Level 1 Level 2 Level 3 Total December 31, 2018 $ — $ — $ 503 $ 503 December 31, 2017 $ — $ — $ 726 $ 726 Individual Forward Sale Commitments with Investors Level 1 Level 2 Level 3 Total December 31, 2018 $ — $ (540) $ (34) $ (574) December 31, 2017 $ — $ (65) $ 51 $ (14) Paired Off Commitments with Investors Level 1 Level 2 Level 3 Total December 31, 2018 $ — $ (64) $ — $ (64) December 31, 2017 $ — $ 53 $ — $ 53
Schedule of Valuation Allowance for Impairment of Recognized Servicing Assets	The following tables present impaired loans and OREO measured at fair value on a nonrecurring basis for which a nonrecurring change in fair value has been recorded during the reporting period. The amounts disclosed below represent the fair values at the time the nonrecurring fair value measurements were evaluated. Impaired Loans Level 1 Level 2 Level 3 Total December 31, 2018 $ — $ — $ 3,894 $ 3,894 December 31, 2017 $ — $ — $ 1,094 $ 1,094 OREO Level 1 Level 2 Level 3 Total December 31, 2018 $ — $ — $ 689 $ 689 December 31, 2017 $ — $ — $ — $ —
Valuation assumptions used in determining the fair value of servicing rights	Shown in the table below is the fair value of financial instruments measured under a Level 3 unobservable input on a recurring and nonrecurring basis at December 31, 2018: Level 3 Significant Range Weighted Fair Value Instruments Valuation Technique Unobservable Inputs (Weighted Average) Average RECURRING Interest rate lock commitments with customers Quoted market prices Pull-through expectations 80% - 99% 95.2 % Individual forward sale commitments with investors Quoted market prices Pull-through expectations 80% - 99% 95.2 % NONRECURRING Impaired loans Fair value of underlying collateral Discount applied to the obtained appraisal 0% - 50% 25.0 % OREO Fair value of collateral Discount applied to the obtained appraisal 0% - 75% 71.1 %
Fair Value, Instruments Classified in Shareholders' Equity Measured on Recurring Basis, Unobservable Input Reconciliation	The following table provides a reconciliation of assets and liabilities measured at fair value using significant unobservable inputs (Level 3) on a recurring basis during the years ended December 31, 2018 and 2017. Net change in fair value for gains/ Purchases (losses) relating to Beginning and Sales and Ending items held at end of Balance issuances settlements Balance at end of year 2018 Interest rate lock commitments with customers $ 726 $ 9,722 $ (9,945) $ 503 $ (223) Individual forward sale commitments with investors 51 850 (935) (34) (85) 2017 Interest rate lock commitments with customers $ 818 $ 14,319 $ (14,411) $ 726 $ (92) Individual forward sale commitments with investors 177 141 (267) 51 (126)
Fair Value, by Balance Sheet Grouping	The following table provides estimated fair values of the Company’s financial instruments at December 31, 2018 and 2017, whether or not recognized at fair value in the Consolidated Balance Sheets: 2018 2017 Carrying Fair Carrying Fair Amount Value Amount Value Financial Assets Level 1 inputs: Cash and cash equivalents $ 32,779 $ 32,779 $ 18,915 $ 18,915 Certificates of deposit at other financial institutions 22,074 22,074 18,108 18,108 Level 2 inputs: Securities available-for-sale, at fair value 97,205 97,205 82,480 82,480 Loans held for sale, at fair value 51,195 51,195 53,463 53,463 FHLB stock, at cost 9,887 9,887 2,871 2,871 Accrued interest receivable 5,761 5,761 3,566 3,566 Paired off commitments with investors — — 53 53 Level 3 inputs: Loans receivable, gross 1,326,238 1,320,341 773,445 780,551 (1) Servicing rights, held at lower of cost or fair value 10,429 14,593 6,795 8,608 Fair value interest rate locks with customers 503 503 726 726 Individual forward sale commitments with investors — — 51 51 Financial Liabilities Level 2 inputs: Deposits 1,274,219 1,261,096 829,842 838,087 Borrowings 137,149 136,873 7,529 7,498 Subordinated note 9,865 10,242 9,845 10,741 Accrued interest payable 344 344 214 214 Paired off commitments with investors 64 64 — — Individual forward sale commitments with investors 540 540 65 65 Level 3 inputs: Individual forward sale commitments with investors 34 34 — — __________________________ (1) Estimated fair values reported at December 31, 2017 were not retroactively valued at exit price.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table presents a reconciliation of the components used to compute basic and diluted earnings per share for the years ended December 31, 2018 and 2017. At or For the Year Ended December 31, Numerator: 2018 2017 Net income (in thousands) $ 24,347 $ 14,085 Denominator: Basic weighted average common shares outstanding 3,698,623 3,094,586 Dilutive shares 171,166 197,114 Diluted weighted average common shares outstanding 3,869,789 3,291,700 Basic earnings per share $ 6.58 $ 4.55 Diluted earnings per share $ 6.29 $ 4.28 Potentially dilutive weighted average share options that were not included in the computation of diluted earnings per share because to do so would be anti-dilutive 11,326 —

Derivatives (Tables)

Derivatives (Tables)	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments	The following tables summarize the Company’s derivative instruments at the dates indicated: December 31, 2018 Fair Value Notional Asset Liability Fallout adjusted interest rate lock commitments with customers $ 29,432 $ 503 $ — Mandatory and best effort forward commitments with investors 24,776 — 34 Forward TBA mortgage-backed securities 51,500 — 540 TBA mortgage-backed securities forward sales paired off with investors 6,500 — 64 December 31, 2017 Fair Value Notional Asset Liability Fallout adjusted interest rate lock commitments with customers $ 31,951 $ 726 $ — Mandatory and best effort forward commitments with investors 12,505 51 — Forward TBA mortgage-backed securities 66,500 — 65 TBA mortgage-backed securities forward sales paired off with investors 36,500 53 —

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock Option Awards	Year Ended December 31, 2018 Dividend yield Expected volatility Risk-free interest rate Expected term in years 6.5 Weighted-average grant date fair value per option granted $ 13.22 The following table presents a summary of the Company’s stock option plan awards during the year ended December 31, 2018 (shown as actual): Weighted-Average Weighted- Remaining Average Contractual Term In Aggregate Shares Exercise Price Years Intrinsic Value Outstanding at January 1, 2018 256,237 $ 16.89 6.36 $ 9,655,010 Granted 100,000 58.60 — — Less exercised 66,133 $ 16.89 — $ 2,453,314 Forfeited or expired — — — — Outstanding at December 31, 2018 290,104 $ 31.27 6.83 $ 4,940,803 Expected to vest, assuming a 0.31% annual forfeiture rate (1) 289,226 $ 31.19 6.82 $ 4,939,069 Exercisable at December 31, 2018 129,304 $ 16.89 5.36 $ 3,360,611 (1) Forfeiture rate has been calculated and estimated to assume a forfeiture of 3.1% of the options forfeited over 10 years.
Summary of Nonvested Awards	The following table presents a summary of the Company’s nonvested awards during the year ended December 31, 2018 (shown as actual): Weighted-Average Grant-Date Fair Value Nonvested Shares Shares Per Share Nonvested at January 1, 2018 36,842 $ 17.63 Granted 25,000 58.60 Less vested 18,421 $ 17.63 Forfeited or expired — — Nonvested at December 31, 2018 43,421 $ 41.22

Business Segments (Tables)

Business Segments (Tables)	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	The tables below summarize the financial results for each segment based primarily on the number of FTEs and assets within each segment for the years ended December 31, 2018 and 2017: At or For the Year Ended December 31, 2018 Home Lending Commercial and Consumer Banking Total Condensed income statement: Net interest income (1) $ 3,324 $ 48,774 $ 52,098 Provision for loan losses (224) (1,316) (1,540) Noninterest income (2) 14,025 12,825 26,850 Noninterest expense (15,894) (32,944) (48,838) Income before provision for income taxes 1,231 27,339 28,570 Provision for income taxes (182) (4,041) (4,223) Net income $ 1,049 $ 23,298 $ 24,347 Total assets (3) $ 246,280 $ 1,375,364 $ 1,621,644 Total average assets at period end $ 229,661 $ 945,052 $ 1,174,713 FTEs 115 309 424 At or For the Year Ended December 31, 2017 Home Lending Commercial and Consumer Banking Total Condensed income statement: Net interest income (1) $ 2,587 $ 38,661 $ 41,248 Provision for loan losses (287) (463) (750) Noninterest income 18,973 5,101 24,074 Noninterest expense (17,052) (26,941) (43,993) Income before provision for income taxes 4,221 16,358 20,579 Provision for income taxes (1,332) (5,162) (6,494) Net income $ 2,889 $ 11,196 $ 14,085 Total assets $ 220,353 $ 761,430 $ 981,783 Total average assets at period end $ 203,379 $ 720,202 $ 923,581 FTEs 119 207 326 ___________________________ (1) Net interest income is the difference between interest earned on assets and the cost of liabilities to fund those assets. Interest earned includes actual interest earned on segment assets and, if the segment has excess liabilities, interest credits for providing funding to the other segment. The cost of liabilities includes interest expense on segment liabilities and, if the segment does not have enough liabilities to fund its assets, a funding charge based on the cost of assigned liabilities to fund segment assets. (2) Barg ain purchase gain of $7.4 million was included in the commercial and consumer banking segment. (3) Increase from prior year relates primarily to the Anchor Acquisition and organic growth.

Goodwill And Other Intangible_2

Goodwill And Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of changes in other intangible assets	Other Intangible Assets Accumulated Gross CDI Amortization Net CDI Balance, December 31, 2016 $ 2,239 $ (522) $ 1,717 Amortization — (400) (400) Balance, December 31, 2017 2,239 (922) 1,317 Amortization — (307) (307) Additions as a result of the Anchor Acquisition 5,251 (44) 5,207 Balance, December 31, 2018 $ 7,490 $ (1,273) $ 6,217
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]	Amortization expense for the CDI is expected to be as follows at December 31, 2018: 2019 760 2020 706 2021 691 2022 691 2023 691 Thereafter 2,678 Total $ 6,217

Basis of Presentation and Sum_3

Basis of Presentation and Summary of Significant Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2018USD ($)segmentitemshares	Dec. 31, 2017USD ($)shares	Jan. 22, 2016item	Jul. 09, 2012shares
Schedule of Accounting Policies [Line Items]
Total ESOP shares (in shares) | shares	254,572	256,733		259,210
Percentage of common shares purchased under ESOP				8.00%
Number of business segments | segment	2
Cash and due from banks and interest-bearing deposits in excess of FDIC insured limits	$ 25,000	$ 15,000
FHLB investment requirement, capital stock amount	$ 1,700,000
FHLB investment requirement, percent of advances from FHLB	4.00%
Federal Home Loan Bank Stock	$ 9,887,000	2,871,000
Impairment of FHLB stock	$ 0	0
Maximum term interest is accrued on delinquent loan	90 days
Maximum term delinquent loan is returned to accrual status	90 days
Minimum term delinquent loan performs under contract terms and returned to accrual status	6 months
Goodwill impairment	$ 0	$ 0
Income tax provision at statutory rate	21.00%	35.00%
Cash on hand and deposit balances with FRB	$ 17,400,000	$ 18,200,000
Marketing and advertising expense	747,000	$ 716,000
Proforma adjustment | ASU 2016-02
Schedule of Accounting Policies [Line Items]
Present value of future lease obligation	5,000,000
Operating lease right of use asset	$ 5,000,000
Building and building improvements | Minimum
Schedule of Accounting Policies [Line Items]
Useful life	25 years
Building and building improvements | Maximum
Schedule of Accounting Policies [Line Items]
Useful life	40 years
Furniture, fixtures and equipment | Minimum
Schedule of Accounting Policies [Line Items]
Useful life	3 years
Furniture, fixtures and equipment | Maximum
Schedule of Accounting Policies [Line Items]
Useful life	10 years
Puget Sound [Member]
Schedule of Accounting Policies [Line Items]
Number of bank branches | item	21
Number of loan production offices | item	8
Tri-Cities, Washington [Member]
Schedule of Accounting Policies [Line Items]
Number of loan production offices | item	1
Bank of America
Schedule of Accounting Policies [Line Items]
Number of bank branches | item			4

Business Combination - Estimate

Business Combination - Estimated Fair Values of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ / shares in Units, $ in Thousands	Nov. 15, 2018	Dec. 31, 2018	Dec. 31, 2017
Liabilities [Abstract]
Bargain purchase gain		$ (7,414)	$ 0
Bank of America
Liabilities [Abstract]
Deposits		$ 120,000	$ 134,600
Anchor Bancorp
Assets.
Cash and cash equivalents	$ 54,558
Securities available-for-sale	19,555
Loans receivable, net	356,275
Premises and equipment, net	11,765
Other real estate owned ("OREO")	689
Deferred tax asset	739
Mortgage servicing rights	782
Core deposit intangible	5,251
Other assets	25,249
Total assets acquired	474,863
Liabilities [Abstract]
Deposits	356,811
Borrowings	36,718
Other liabilities	9,349
Total liabilities assumed	$ 402,878
Pre-tax discount of time deposits to core deposits (as a percent)	0.65%
Common stock price (per share)	$ 46.54
Common stock outstanding	725,518
Bargain purchase gain	$ (7,414)
Number of shares received	0.291
Consideration received by anchor shareholder in cash for each share	$ 12.40
Acquired Book Value | Anchor Bancorp
Assets.
Cash and cash equivalents	$ 54,558
Securities available-for-sale	19,609
Loans receivable, net	361,596
Premises and equipment, net	8,411
Other real estate owned ("OREO")	689
Deferred tax asset	4,097
Mortgage servicing rights	218
Other assets	25,231
Total assets acquired	474,409
Liabilities [Abstract]
Deposits	357,863
Borrowings	37,000
Other liabilities	9,286
Total liabilities assumed	404,149
Fair Value Adjustments | Anchor Bancorp
Assets.
Securities available-for-sale	(54)
Loans receivable, net	(5,321)
Premises and equipment, net	3,354
Deferred tax asset	(3,358)
Mortgage servicing rights	564
Core deposit intangible	5,251
Other assets	18
Total assets acquired	454
Liabilities [Abstract]
Deposits	(1,052)
Borrowings	(282)
Other liabilities	63
Total liabilities assumed	(1,271)
Carrying Amount | Anchor Bancorp
Assets.
Cash and cash equivalents	54,558
Securities available-for-sale	19,555
Loans receivable, net	356,275
Premises and equipment, net	11,765
Other real estate owned ("OREO")	689
Deferred tax asset	739
Mortgage servicing rights	782
Core deposit intangible	5,251
Other assets	25,249
Total assets acquired	474,863
Liabilities [Abstract]
Deposits	356,811
Borrowings	36,718
Other liabilities	9,349
Total liabilities assumed	$ 402,878
Interest Income [Member] | Anchor Bancorp
Liabilities [Abstract]
Estimated amortization period		60 months
Expense [Member] | Anchor Bancorp
Liabilities [Abstract]
Estimated amortization period		10 years

Business Combination - Amount R

Business Combination - Amount Recognized for Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Nov. 15, 2018	Dec. 31, 2018	Dec. 31, 2017
Fair value of net assets and identifiable intangible assets acquired
Bargain purchase gain		$ (7,414)	$ 0
Bank of America
Fair value of liabilities assumed:
Deposits		$ 120,000	$ 134,600
Anchor Bancorp
Business Acquisition [Line Items]
Fair value of FS Bancorp common stock at $46.54 (1) per share for 725,518 shares	$ 33,766
Cash paid	30,805
Total purchase price	64,571
Fair value of assets acquired:
Cash and cash equivalents	54,558
Securities available-for-sale	19,555
Loans receivable, net	356,275
Premises and equipment, net	11,765
OREO	689
Deferred tax asset	739
Mortgage servicing rights	782
Core deposit intangible, net	5,251
Other assets	25,249
Total assets acquired	474,863
Fair value of liabilities assumed:
Deposits	356,811
Borrowings	36,718
Other liabilities	9,349
Total liabilities assumed	402,878
Fair value of net assets and identifiable intangible assets acquired
Total fair value of identifiable net assets	71,985
Bargain purchase gain	$ (7,414)

Securities Available-for-sale -

Securities Available-for-sale - Available-for-sale securities reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Debt and Equity Securities, FV-NI [Line Items]
Amortized cost	$ 99,089	$ 83,085
Unrealized Gains	138	269
Unrealized Losses	2,022	874
Estimated Fair Values	97,205	82,480
U.S. agency securities
Debt and Equity Securities, FV-NI [Line Items]
Amortized cost	16,052	9,077
Unrealized Gains	32	49
Unrealized Losses	197	11
Estimated Fair Values	15,887	9,115
Corporate securities
Debt and Equity Securities, FV-NI [Line Items]
Amortized cost	7,074	7,113
Unrealized Gains	0	9
Unrealized Losses	209	96
Estimated Fair Values	6,865	7,026
Municipal bonds
Debt and Equity Securities, FV-NI [Line Items]
Amortized cost	14,446	12,720
Unrealized Gains	23	148
Unrealized Losses	275	82
Estimated Fair Values	14,194	12,786
Mortgage-backed securities
Debt and Equity Securities, FV-NI [Line Items]
Amortized cost	45,827	40,161
Unrealized Gains	83	63
Unrealized Losses	1,074	490
Estimated Fair Values	44,836	39,734
U.S. Small Business Administration securities
Debt and Equity Securities, FV-NI [Line Items]
Amortized cost	15,690	14,014
Unrealized Gains	0	0
Unrealized Losses	267	195
Estimated Fair Values	$ 15,423	$ 13,819

Securities Available-for-sale_2

Securities Available-for-sale - Narrative (Details)	12 Months Ended
	Dec. 31, 2018USD ($)securityitem	Dec. 31, 2017USD ($)securityitem
Debt and Equity Securities, FV-NI [Line Items]
Number of investments with unrealized losses of less than one year | item	14	21
Number of investments with unrealized losses of more than one year | item	48	17
Other than temporary impairment write-downs	$ 0	$ 0
1st Security Bank of Washington
Debt and Equity Securities, FV-NI [Line Items]
Number of securities pledged and held at FHLB | security	11	9
Pledged securities for FHLB	$ 13,700,000	$ 10,700,000
Public deposits	19,900,000	7,600,000
Collateral requirement	$ 8,400,000	$ 3,200,000

Securities Available-for-sale_3

Securities Available-for-sale - Investments with Unrealized Losses Policy (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value
Unrealized loss position, Less than 12 Months, Fair Value	$ 17,315	$ 32,209
Unrealized loss position, 12 Months or Longer, Fair Value	65,501	24,493
Unrealized loss position, Fair Value	82,816	56,702
Unrealized Losses
Unrealized loss position, Less than 12 Months, Unrealized Losses	123	331
Unrealized loss position, 12 Months or Longer, Unrealized Losses	1,899	543
Unrealized loss position, Unrealized Losses	2,022	874
U.S. agency securities
Fair Value
Unrealized loss position, Less than 12 Months, Fair Value	6,018	2,987
Unrealized loss position, 12 Months or Longer, Fair Value	4,822	0
Unrealized loss position, Fair Value	10,840	2,987
Unrealized Losses
Unrealized loss position, Less than 12 Months, Unrealized Losses	25	11
Unrealized loss position, 12 Months or Longer, Unrealized Losses	172	0
Unrealized loss position, Unrealized Losses	197	11
Corporate securities
Fair Value
Unrealized loss position, Less than 12 Months, Fair Value	975	4,102
Unrealized loss position, 12 Months or Longer, Fair Value	5,890	1,915
Unrealized loss position, Fair Value	6,865	6,017
Unrealized Losses
Unrealized loss position, Less than 12 Months, Unrealized Losses	25	15
Unrealized loss position, 12 Months or Longer, Unrealized Losses	184	81
Unrealized loss position, Unrealized Losses	209	96
Municipal bonds
Fair Value
Unrealized loss position, Less than 12 Months, Fair Value	2,098	5,982
Unrealized loss position, 12 Months or Longer, Fair Value	8,787	0
Unrealized loss position, Fair Value	10,885	5,982
Unrealized Losses
Unrealized loss position, Less than 12 Months, Unrealized Losses	22	82
Unrealized loss position, 12 Months or Longer, Unrealized Losses	253	0
Unrealized loss position, Unrealized Losses	275	82
Mortgage-backed securities
Fair Value
Unrealized loss position, Less than 12 Months, Fair Value	6,266	7,262
Unrealized loss position, 12 Months or Longer, Fair Value	32,537	20,635
Unrealized loss position, Fair Value	38,803	27,897
Unrealized Losses
Unrealized loss position, Less than 12 Months, Unrealized Losses	40	61
Unrealized loss position, 12 Months or Longer, Unrealized Losses	1,034	429
Unrealized loss position, Unrealized Losses	1,074	490
U.S. Small Business Administration securities
Fair Value
Unrealized loss position, Less than 12 Months, Fair Value	1,958	11,876
Unrealized loss position, 12 Months or Longer, Fair Value	13,465	1,943
Unrealized loss position, Fair Value	15,423	13,819
Unrealized Losses
Unrealized loss position, Less than 12 Months, Unrealized Losses	11	162
Unrealized loss position, 12 Months or Longer, Unrealized Losses	256	33
Unrealized loss position, Unrealized Losses	$ 267	$ 195

Securities Available-for-sale_4

Securities Available-for-sale - Available for Sale Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Amortized Cost
Mortgage-backed securities	$ 45,827	$ 40,161
Amortized Cost	99,089	83,085
Fair Value
Mortgage-backed securities	44,836	39,734
Estimated Fair Values	97,205	82,480
U.S. agency securities
Amortized Cost
Due after one year through five years	1,043	0
Due after five years through ten years	10,011	4,079
Due after ten years	4,998	4,998
Subtotal	16,052	9,077
Amortized Cost	16,052	9,077
Fair Value
Due after one year through five years	1,040	0
Due after five years through ten years	9,941	4,124
Due after ten years	4,906	4,991
Subtotal	15,887	9,115
Estimated Fair Values	15,887	9,115
Corporate securities
Amortized Cost
Due after one year through five years	6,077	5,117
Due after five years through ten years	997	1,996
Subtotal	7,074	7,113
Amortized Cost	7,074	7,113
Fair Value
Due after one year through five years	5,947	5,111
Due after five years through ten years	918	1,915
Subtotal	6,865	7,026
Estimated Fair Values	6,865	7,026
Municipal bonds
Amortized Cost
Due after one year through five years	2,659	2,001
Due after five years through ten years	2,610	4,111
Due after ten years	9,177	6,608
Subtotal	14,446	12,720
Amortized Cost	14,446	12,720
Fair Value
Due after one year through five years	2,570	2,026
Due after five years through ten years	2,592	4,206
Due after ten years	9,032	6,554
Subtotal	14,194	12,786
Estimated Fair Values	14,194	12,786
Mortgage-backed securities
Amortized Cost
Amortized Cost	45,827	40,161
Fair Value
Estimated Fair Values	44,836	39,734
Federal National Mortgage Association ("FNMA")
Amortized Cost
Mortgage-backed securities	30,554	23,310
Fair Value
Mortgage-backed securities	30,026	23,091
Federal Home Loan Mortgage Corporation ("FHLMC")
Amortized Cost
Mortgage-backed securities	10,301	10,818
Fair Value
Mortgage-backed securities	9,961	10,629
Government National Mortgage Association ("GNMA")
Amortized Cost
Mortgage-backed securities	4,972	6,033
Fair Value
Mortgage-backed securities	4,849	6,014
U.S. Small Business Administration securities
Amortized Cost
Due after five years through ten years	13,828	12,065
Due after ten years	1,862	1,949
Subtotal	15,690	14,014
Amortized Cost	15,690	14,014
Fair Value
Due after five years through ten years	13,581	11,896
Due after ten years	1,842	1,923
Subtotal	15,423	13,819
Estimated Fair Values	$ 15,423	$ 13,819

Securities Available-for-sale_5

Securities Available-for-sale - Sales of Available for Sale Securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Proceeds	$ 24,312	$ 39,103
Gross Gains	185	413
Gross Losses	$ (14)	$ (33)

Loans Receivable and Allowanc_3

Loans Receivable and Allowance For Loan Losses - Composition of Loan Portfolio (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 1,326,238	$ 773,445
Allowance for loan losses	(12,349)	(10,756)
Deferred costs and fees, net	(2,907)	(2,708)
Premiums on purchased loans	1,537	1,577
Loans receivable, net	1,312,519	761,558
REAL ESTATE LOANS | REAL ESTATE LOANS.
Financing Receivable, Recorded Investment [Line Items]
Total loans	846,323	440,074
REAL ESTATE LOANS | Commercial
Financing Receivable, Recorded Investment [Line Items]
Total loans	204,699	63,611
REAL ESTATE LOANS | Construction and development
Financing Receivable, Recorded Investment [Line Items]
Total loans	247,306	143,068
REAL ESTATE LOANS | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total loans	40,258	25,289
REAL ESTATE LOANS | One-to-four-family (1)
Financing Receivable, Recorded Investment [Line Items]
Total loans	249,397	163,655
REAL ESTATE LOANS | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Total loans	104,663	44,451
CONSUMER LOANS | CONSUMER LOANS.
Financing Receivable, Recorded Investment [Line Items]
Total loans	275,473	208,668
CONSUMER LOANS | Indirect home improvement
Financing Receivable, Recorded Investment [Line Items]
Total loans	167,793	130,176
CONSUMER LOANS | Solar
Financing Receivable, Recorded Investment [Line Items]
Total loans	44,433	41,049
CONSUMER LOANS | Marine
Financing Receivable, Recorded Investment [Line Items]
Total loans	57,822	35,397
CONSUMER LOANS | Other consumer
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,425	2,046
COMMERCIAL BUSINESS LOANS. | COMMERCIAL BUSINESS LOANS
Financing Receivable, Recorded Investment [Line Items]
Total loans	204,442	124,703
COMMERCIAL BUSINESS LOANS. | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total loans	138,686	83,306
COMMERCIAL BUSINESS LOANS. | Warehouse lending
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 65,756	$ 41,397

Loans Receivable and Allowanc_4

Loans Receivable and Allowance For Loan Losses - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)item	Nov. 15, 2018USD ($)	Dec. 31, 2017USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Receivable, Net | $	$ 1,312,519		$ 761,558
Number of loan portfolio segments | item	3
Multi-family | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of units in real estate property | item	5
Anchor Bancorp
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Receivable, Net | $		$ 328,200

Loans Receivable and Allowanc_5

Loans Receivable and Allowance For Loan Losses - Allowance for Loan Losses by Loan Categories (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
ALLOWANCE FOR LOAN LOSSES
Beginning balance	$ 10,756	$ 10,211
Provision for loan loss	1,540	750
Charge-offs	(940)	(930)
Recoveries	993	725
Net recoveries (charge-offs)	53	(205)
Loans individually evaluated for impairment	975	89
Loans collectively evaluated for impairment	11,374	10,667
Ending balance	12,349	10,756
LOANS RECEIVABLE
Loans individually evaluated for impairment	2,947	1,094
Loans collectively evaluated for impairment	1,323,291	772,351
Total loans receivable	1,326,238	773,445
REAL ESTATE LOANS
ALLOWANCE FOR LOAN LOSSES
Beginning balance	4,770	3,547
Provision for loan loss	953	1,253
Charge-offs	(4)	(65)
Recoveries	42	35
Net recoveries (charge-offs)	38	(30)
Loans individually evaluated for impairment	125	21
Loans collectively evaluated for impairment	5,636	4,749
Ending balance	5,761	4,770
LOANS RECEIVABLE
Loans individually evaluated for impairment	834	348
Loans collectively evaluated for impairment	845,489	439,726
Total loans receivable	846,323	440,074
REAL ESTATE LOANS | REAL ESTATE LOANS.
LOANS RECEIVABLE
Total loans receivable	846,323	440,074
CONSUMER LOANS
ALLOWANCE FOR LOAN LOSSES
Beginning balance	2,814	2,082
Provision for loan loss	526	884
Charge-offs	(936)	(832)
Recoveries	947	680
Net recoveries (charge-offs)	11	(152)
Loans individually evaluated for impairment	150	68
Loans collectively evaluated for impairment	3,201	2,746
Ending balance	3,351	2,814
LOANS RECEIVABLE
Loans individually evaluated for impairment	428	195
Loans collectively evaluated for impairment	275,045	208,473
Total loans receivable	275,473	208,668
CONSUMER LOANS | CONSUMER LOANS.
LOANS RECEIVABLE
Total loans receivable	275,473	208,668
CONSUMER LOANS | Other consumer
LOANS RECEIVABLE
Total loans receivable	5,425	2,046
COMMERCIAL BUSINESS LOANS.
ALLOWANCE FOR LOAN LOSSES
Beginning balance	2,014	2,675
Provision for loan loss	1,173	(638)
Charge-offs	0	(33)
Recoveries	4	10
Net recoveries (charge-offs)	4	(23)
Loans individually evaluated for impairment	700	0
Loans collectively evaluated for impairment	2,491	2,014
Ending balance	3,191	2,014
LOANS RECEIVABLE
Loans individually evaluated for impairment	1,685	551
Loans collectively evaluated for impairment	202,757	124,152
Total loans receivable	204,442	124,703
COMMERCIAL BUSINESS LOANS. | COMMERCIAL BUSINESS LOANS
LOANS RECEIVABLE
Total loans receivable	204,442	124,703
Unallocated
ALLOWANCE FOR LOAN LOSSES
Beginning balance	1,158	1,907
Provision for loan loss	(1,112)	(749)
Charge-offs	0	0
Recoveries	0	0
Net recoveries (charge-offs)	0	0
Loans individually evaluated for impairment	0	0
Loans collectively evaluated for impairment	46	1,158
Ending balance	46	1,158
LOANS RECEIVABLE
Loans individually evaluated for impairment	0	0
Loans collectively evaluated for impairment	0	0
Total loans receivable	$ 0	$ 0

Loans Receivable and Allowanc_6

Loans Receivable and Allowance For Loan Losses - Aging Analysis of Past Due Loans (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)loan	Dec. 31, 2017USD ($)loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 4,701	$ 1,588
Current	1,321,537	771,857
Total loans receivable	1,326,238	773,445
Financing Receivable, Recorded Investment, Nonaccrual Status	3,894	1,039
30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,051	568
60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	898	785
90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,752	235
REAL ESTATE LOANS
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans receivable	846,323	440,074
REAL ESTATE LOANS | REAL ESTATE LOANS.
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,223	400
Current	843,100	439,674
Total loans receivable	846,323	440,074
Financing Receivable, Recorded Investment, Nonaccrual Status	1,781	293
REAL ESTATE LOANS | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Current	204,699	63,611
Total loans receivable	204,699	63,611
Financing Receivable, Recorded Investment, Nonaccrual Status	0	0
REAL ESTATE LOANS | Construction and development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Current	247,306	143,068
Total loans receivable	247,306	143,068
Financing Receivable, Recorded Investment, Nonaccrual Status	0	0
REAL ESTATE LOANS | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	427	258
Current	39,831	25,031
Total loans receivable	40,258	25,289
Financing Receivable, Recorded Investment, Nonaccrual Status	229	151
REAL ESTATE LOANS | One-to-four-family (1)
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,796	142
Current	246,601	163,513
Total loans receivable	249,397	163,655
Financing Receivable, Recorded Investment, Nonaccrual Status	1,552	142
REAL ESTATE LOANS | Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Current	104,663	44,451
Total loans receivable	104,663	44,451
Financing Receivable, Recorded Investment, Nonaccrual Status	0	0
REAL ESTATE LOANS | 30-59 Days Past Due | REAL ESTATE LOANS.
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,432	264
REAL ESTATE LOANS | 30-59 Days Past Due | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
REAL ESTATE LOANS | 30-59 Days Past Due | Construction and development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
REAL ESTATE LOANS | 30-59 Days Past Due | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	158	122
REAL ESTATE LOANS | 30-59 Days Past Due | One-to-four-family (1)
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,274	142
REAL ESTATE LOANS | 30-59 Days Past Due | Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
REAL ESTATE LOANS | 60-89 Days Past Due | REAL ESTATE LOANS.
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	204	0
REAL ESTATE LOANS | 60-89 Days Past Due | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
REAL ESTATE LOANS | 60-89 Days Past Due | Construction and development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
REAL ESTATE LOANS | 60-89 Days Past Due | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	40	0
REAL ESTATE LOANS | 60-89 Days Past Due | One-to-four-family (1)
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	164	0
REAL ESTATE LOANS | 60-89 Days Past Due | Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
REAL ESTATE LOANS | 90 Days or More Past Due | REAL ESTATE LOANS.
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,587	136
REAL ESTATE LOANS | 90 Days or More Past Due | Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
REAL ESTATE LOANS | 90 Days or More Past Due | Construction and development
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
REAL ESTATE LOANS | 90 Days or More Past Due | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	229	136
REAL ESTATE LOANS | 90 Days or More Past Due | One-to-four-family (1)
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,358	0
REAL ESTATE LOANS | 90 Days or More Past Due | Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
CONSUMER LOANS
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans receivable	275,473	208,668
CONSUMER LOANS | CONSUMER LOANS.
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,047	637
Current	274,426	208,031
Total loans receivable	275,473	208,668
Financing Receivable, Recorded Investment, Nonaccrual Status	428	195
CONSUMER LOANS | Indirect home improvement
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	747	569
Current	167,046	129,607
Total loans receivable	167,793	130,176
Financing Receivable, Recorded Investment, Nonaccrual Status	367	195
CONSUMER LOANS | Solar
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	146	68
Current	44,287	40,981
Total loans receivable	44,433	41,049
Financing Receivable, Recorded Investment, Nonaccrual Status	41	0
CONSUMER LOANS | Marine
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	50	0
Current	57,772	35,397
Total loans receivable	57,822	35,397
Financing Receivable, Recorded Investment, Nonaccrual Status	18	0
CONSUMER LOANS | Other consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	104	0
Current	5,321	2,046
Total loans receivable	5,425	2,046
Financing Receivable, Recorded Investment, Nonaccrual Status	2	0
CONSUMER LOANS | 30-59 Days Past Due | CONSUMER LOANS.
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	619	304
CONSUMER LOANS | 30-59 Days Past Due | Indirect home improvement
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	438	255
CONSUMER LOANS | 30-59 Days Past Due | Solar
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	62	49
CONSUMER LOANS | 30-59 Days Past Due | Marine
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	50	0
CONSUMER LOANS | 30-59 Days Past Due | Other consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	69	0
CONSUMER LOANS | 60-89 Days Past Due | CONSUMER LOANS.
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	263	234
CONSUMER LOANS | 60-89 Days Past Due | Indirect home improvement
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	196	215
CONSUMER LOANS | 60-89 Days Past Due | Solar
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	43	19
CONSUMER LOANS | 60-89 Days Past Due | Marine
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
CONSUMER LOANS | 60-89 Days Past Due | Other consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	24	0
CONSUMER LOANS | 90 Days or More Past Due | CONSUMER LOANS.
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	165	99
CONSUMER LOANS | 90 Days or More Past Due | Indirect home improvement
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	113	99
CONSUMER LOANS | 90 Days or More Past Due | Solar
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	41	0
CONSUMER LOANS | 90 Days or More Past Due | Marine
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
CONSUMER LOANS | 90 Days or More Past Due | Other consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 11	$ 0
Number of loans | loan	2	0
COMMERCIAL BUSINESS LOANS.
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans receivable	$ 204,442	$ 124,703
COMMERCIAL BUSINESS LOANS. | COMMERCIAL BUSINESS LOANS
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	431	551
Current	204,011	124,152
Total loans receivable	204,442	124,703
Financing Receivable, Recorded Investment, Nonaccrual Status	1,685	551
COMMERCIAL BUSINESS LOANS. | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	431	551
Current	138,255	82,755
Total loans receivable	138,686	83,306
Financing Receivable, Recorded Investment, Nonaccrual Status	1,685	551
COMMERCIAL BUSINESS LOANS. | Warehouse lending
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Current	65,756	41,397
Total loans receivable	65,756	41,397
Financing Receivable, Recorded Investment, Nonaccrual Status	0	0
COMMERCIAL BUSINESS LOANS. | 30-59 Days Past Due | COMMERCIAL BUSINESS LOANS
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
COMMERCIAL BUSINESS LOANS. | 30-59 Days Past Due | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
COMMERCIAL BUSINESS LOANS. | 30-59 Days Past Due | Warehouse lending
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
COMMERCIAL BUSINESS LOANS. | 60-89 Days Past Due | COMMERCIAL BUSINESS LOANS
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	431	551
COMMERCIAL BUSINESS LOANS. | 60-89 Days Past Due | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	431	551
COMMERCIAL BUSINESS LOANS. | 60-89 Days Past Due | Warehouse lending
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
COMMERCIAL BUSINESS LOANS. | 90 Days or More Past Due | COMMERCIAL BUSINESS LOANS
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
COMMERCIAL BUSINESS LOANS. | 90 Days or More Past Due | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
COMMERCIAL BUSINESS LOANS. | 90 Days or More Past Due | Warehouse lending
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 0	$ 0

Loans Receivable and Allowanc_7

Loans Receivable and Allowance For Loan Losses - Financing Receivables, Related Allowance Recorded and No Related Allowance Recorder (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Unpaid Principal Balance, with no related allowance recorded		$ 769
Unpaid Principal Balance, with related allowance recorded	$ 3,665	337
Impaired Financing Receivable, Unpaid Principal Balance, Total	3,894	1,106
Impaired Financing Receivable, Write-downs [Abstract]
Impairment		(12)
Write-downs with related allowance recorded	0	0
Write-downs	0	(12)
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment, with no related allowance recorded		757
Recorded Investment, with related allowance recorded	3,665	337
Recorded Investment	3,894	1,094
Impaired Financing Receivable Related Allowance Abstract
Related Allowance, with no related allowance recorded		0
Related Allowance, with related allowance recorded	975	89
Related Allowance	975	89
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment, with no related allowance recorded	1,123	826
Average Recorded Investment, with related allowance recorded	2,556	423
Impaired Financing Receivable, Average Recorded Investment	3,679	1,249
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Interest Income Recognized, with no related allowance recorded	8	27
Interest Income Recognized, with related allowance recorded	146	20
Impaired Financing Receivable, with No Related Allowance, Interest Income, Cash Basis Method	154	47
REAL ESTATE LOANS | REAL ESTATE LOANS.
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Unpaid Principal Balance, with no related allowance recorded		218
Impaired Financing Receivable, Write-downs [Abstract]
Impairment		(12)
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment, with no related allowance recorded		206
Impaired Financing Receivable Related Allowance Abstract
Related Allowance, with no related allowance recorded		0
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment, with no related allowance recorded	1,123	275
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Interest Income Recognized, with no related allowance recorded	8	3
REAL ESTATE LOANS | Home equity
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Unpaid Principal Balance, with no related allowance recorded	229	151
Impaired Financing Receivable, Write-downs [Abstract]
Impairment	0	0
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment, with no related allowance recorded	229	151
Impaired Financing Receivable Related Allowance Abstract
Related Allowance, with no related allowance recorded	0	0
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment, with no related allowance recorded	404	219
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Interest Income Recognized, with no related allowance recorded	8	0
REAL ESTATE LOANS | One-to-four-family (1)
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Unpaid Principal Balance, with no related allowance recorded		67
Unpaid Principal Balance, with related allowance recorded	1,552	142
Impaired Financing Receivable, Write-downs [Abstract]
Impairment		(12)
Write-downs with related allowance recorded	0	0
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment, with no related allowance recorded		55
Recorded Investment, with related allowance recorded	1,552	142
Impaired Financing Receivable Related Allowance Abstract
Related Allowance, with no related allowance recorded		0
Related Allowance, with related allowance recorded	125	21
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment, with no related allowance recorded	719	56
Average Recorded Investment, with related allowance recorded	1,030	142
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Interest Income Recognized, with no related allowance recorded	0	3
Interest Income Recognized, with related allowance recorded	28	4
CONSUMER LOANS | CONSUMER LOANS.
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Unpaid Principal Balance, with related allowance recorded	428	195
Impaired Financing Receivable, Write-downs [Abstract]
Write-downs with related allowance recorded	0	0
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment, with related allowance recorded	428	195
Impaired Financing Receivable Related Allowance Abstract
Related Allowance, with related allowance recorded	150	68
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment, with related allowance recorded	338	281
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Interest Income Recognized, with related allowance recorded	37	16
COMMERCIAL BUSINESS LOANS. | COMMERCIAL BUSINESS LOANS
Impaired Financing Receivable, Unpaid Principal Balance [Abstract]
Unpaid Principal Balance, with no related allowance recorded		551
Unpaid Principal Balance, with related allowance recorded	1,685
Impaired Financing Receivable, Write-downs [Abstract]
Impairment		0
Write-downs with related allowance recorded	0
Impaired Financing Receivable, Recorded Investment [Abstract]
Recorded Investment, with no related allowance recorded		551
Recorded Investment, with related allowance recorded	1,685
Impaired Financing Receivable Related Allowance Abstract
Related Allowance, with no related allowance recorded		0
Related Allowance, with related allowance recorded	700
Impaired Financing Receivable, Average Recorded Investment [Abstract]
Average Recorded Investment, with no related allowance recorded	0	551
Average Recorded Investment, with related allowance recorded	1,188	0
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]
Interest Income Recognized, with no related allowance recorded	0	24
Interest Income Recognized, with related allowance recorded	$ 81	$ 0

Loans Receivable and Allowanc_8

Loans Receivable and Allowance For Loan Losses - Loans by Credit Quality Indicator (Details)	12 Months Ended
	Dec. 31, 2018USD ($)loan	Dec. 31, 2017USD ($)loan
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 1,326,238,000	$ 773,445,000
Number of reported TDR loan modified previous 12 months and subsequently defaulted | loan	0
Number of TDR loans | loan		0
Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 1,303,884,000	$ 764,318,000
Watch
Financing Receivable, Recorded Investment [Line Items]
Total loans	14,107,000	673,000
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	254,000	1,979,000
Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	7,993,000	6,475,000
Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Loss
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
REAL ESTATE LOANS
Financing Receivable, Recorded Investment [Line Items]
Total loans	846,323,000	440,074,000
Mortgage Loans in Process of Foreclosure, Amount	261,000	0
REAL ESTATE LOANS | REAL ESTATE LOANS.
Financing Receivable, Recorded Investment [Line Items]
Total loans	846,323,000	440,074,000
REAL ESTATE LOANS | Commercial
Financing Receivable, Recorded Investment [Line Items]
Total loans	204,699,000	63,611,000
REAL ESTATE LOANS | Construction and development
Financing Receivable, Recorded Investment [Line Items]
Total loans	247,306,000	143,068,000
REAL ESTATE LOANS | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total loans	40,258,000	25,289,000
REAL ESTATE LOANS | One-to-four-family (1)
Financing Receivable, Recorded Investment [Line Items]
Total loans	249,397,000	163,655,000
REAL ESTATE LOANS | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Total loans	104,663,000	44,451,000
REAL ESTATE LOANS | Pass | REAL ESTATE LOANS.
Financing Receivable, Recorded Investment [Line Items]
Total loans	839,002,000	438,227,000
REAL ESTATE LOANS | Pass | Commercial
Financing Receivable, Recorded Investment [Line Items]
Total loans	203,557,000	62,057,000
REAL ESTATE LOANS | Pass | Construction and development
Financing Receivable, Recorded Investment [Line Items]
Total loans	244,577,000	143,068,000
REAL ESTATE LOANS | Pass | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total loans	39,846,000	25,138,000
REAL ESTATE LOANS | Pass | One-to-four-family (1)
Financing Receivable, Recorded Investment [Line Items]
Total loans	247,575,000	163,513,000
REAL ESTATE LOANS | Pass | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Total loans	103,447,000	44,451,000
REAL ESTATE LOANS | Watch | REAL ESTATE LOANS.
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,294,000	0
REAL ESTATE LOANS | Watch | Commercial
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,142,000	0
REAL ESTATE LOANS | Watch | Construction and development
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,729,000	0
REAL ESTATE LOANS | Watch | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
REAL ESTATE LOANS | Watch | One-to-four-family (1)
Financing Receivable, Recorded Investment [Line Items]
Total loans	207,000	0
REAL ESTATE LOANS | Watch | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,216,000	0
REAL ESTATE LOANS | Special Mention | REAL ESTATE LOANS.
Financing Receivable, Recorded Investment [Line Items]
Total loans	246,000	1,554,000
REAL ESTATE LOANS | Special Mention | Commercial
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	1,554,000
REAL ESTATE LOANS | Special Mention | Construction and development
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
REAL ESTATE LOANS | Special Mention | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total loans	183,000	0
REAL ESTATE LOANS | Special Mention | One-to-four-family (1)
Financing Receivable, Recorded Investment [Line Items]
Total loans	63,000	0
REAL ESTATE LOANS | Special Mention | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
REAL ESTATE LOANS | Substandard | REAL ESTATE LOANS.
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,781,000	293,000
REAL ESTATE LOANS | Substandard | Commercial
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
REAL ESTATE LOANS | Substandard | Construction and development
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
REAL ESTATE LOANS | Substandard | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total loans	229,000	151,000
REAL ESTATE LOANS | Substandard | One-to-four-family (1)
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,552,000	142,000
REAL ESTATE LOANS | Substandard | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
REAL ESTATE LOANS | Doubtful | REAL ESTATE LOANS.
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
REAL ESTATE LOANS | Doubtful | Commercial
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
REAL ESTATE LOANS | Doubtful | Construction and development
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
REAL ESTATE LOANS | Doubtful | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
REAL ESTATE LOANS | Doubtful | One-to-four-family (1)
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
REAL ESTATE LOANS | Doubtful | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
REAL ESTATE LOANS | Loss | REAL ESTATE LOANS.
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
REAL ESTATE LOANS | Loss | Commercial
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
REAL ESTATE LOANS | Loss | Construction and development
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
REAL ESTATE LOANS | Loss | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
REAL ESTATE LOANS | Loss | One-to-four-family (1)
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
REAL ESTATE LOANS | Loss | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
CONSUMER LOANS
Financing Receivable, Recorded Investment [Line Items]
Total loans	275,473,000	208,668,000
CONSUMER LOANS | CONSUMER LOANS.
Financing Receivable, Recorded Investment [Line Items]
Total loans	275,473,000	208,668,000
CONSUMER LOANS | Indirect home improvement
Financing Receivable, Recorded Investment [Line Items]
Total loans	167,793,000	130,176,000
CONSUMER LOANS | Solar
Financing Receivable, Recorded Investment [Line Items]
Total loans	44,433,000	41,049,000
CONSUMER LOANS | Marine
Financing Receivable, Recorded Investment [Line Items]
Total loans	57,822,000	35,397,000
CONSUMER LOANS | Other consumer
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,425,000	2,046,000
CONSUMER LOANS | Pass | CONSUMER LOANS.
Financing Receivable, Recorded Investment [Line Items]
Total loans	275,037,000	208,425,000
CONSUMER LOANS | Pass | Indirect home improvement
Financing Receivable, Recorded Investment [Line Items]
Total loans	167,426,000	129,981,000
CONSUMER LOANS | Pass | Solar
Financing Receivable, Recorded Investment [Line Items]
Total loans	44,392,000	41,049,000
CONSUMER LOANS | Pass | Marine
Financing Receivable, Recorded Investment [Line Items]
Total loans	57,804,000	35,397,000
CONSUMER LOANS | Pass | Other consumer
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,415,000	1,998,000
CONSUMER LOANS | Watch | CONSUMER LOANS.
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
CONSUMER LOANS | Watch | Indirect home improvement
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
CONSUMER LOANS | Watch | Solar
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
CONSUMER LOANS | Watch | Marine
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
CONSUMER LOANS | Watch | Other consumer
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
CONSUMER LOANS | Special Mention | CONSUMER LOANS.
Financing Receivable, Recorded Investment [Line Items]
Total loans	8,000	0
CONSUMER LOANS | Special Mention | Indirect home improvement
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
CONSUMER LOANS | Special Mention | Solar
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
CONSUMER LOANS | Special Mention | Marine
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
CONSUMER LOANS | Special Mention | Other consumer
Financing Receivable, Recorded Investment [Line Items]
Total loans	8,000	0
CONSUMER LOANS | Substandard | CONSUMER LOANS.
Financing Receivable, Recorded Investment [Line Items]
Total loans	428,000	243,000
CONSUMER LOANS | Substandard | Indirect home improvement
Financing Receivable, Recorded Investment [Line Items]
Total loans	367,000	195,000
CONSUMER LOANS | Substandard | Solar
Financing Receivable, Recorded Investment [Line Items]
Total loans	41,000	0
CONSUMER LOANS | Substandard | Marine
Financing Receivable, Recorded Investment [Line Items]
Total loans	18,000	0
CONSUMER LOANS | Substandard | Other consumer
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,000	48,000
CONSUMER LOANS | Doubtful | CONSUMER LOANS.
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
CONSUMER LOANS | Doubtful | Indirect home improvement
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
CONSUMER LOANS | Doubtful | Solar
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
CONSUMER LOANS | Doubtful | Marine
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
CONSUMER LOANS | Doubtful | Other consumer
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
CONSUMER LOANS | Loss | CONSUMER LOANS.
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
CONSUMER LOANS | Loss | Indirect home improvement
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
CONSUMER LOANS | Loss | Solar
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
CONSUMER LOANS | Loss | Marine
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
CONSUMER LOANS | Loss | Other consumer
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
COMMERCIAL BUSINESS LOANS.
Financing Receivable, Recorded Investment [Line Items]
Total loans	204,442,000	124,703,000
COMMERCIAL BUSINESS LOANS. | COMMERCIAL BUSINESS LOANS
Financing Receivable, Recorded Investment [Line Items]
Total loans	204,442,000	124,703,000
COMMERCIAL BUSINESS LOANS. | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total loans	138,686,000	83,306,000
COMMERCIAL BUSINESS LOANS. | Warehouse lending
Financing Receivable, Recorded Investment [Line Items]
Total loans	65,756,000	41,397,000
COMMERCIAL BUSINESS LOANS. | Pass | COMMERCIAL BUSINESS LOANS
Financing Receivable, Recorded Investment [Line Items]
Total loans	189,845,000	117,666,000
COMMERCIAL BUSINESS LOANS. | Pass | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total loans	124,089,000	76,942,000
COMMERCIAL BUSINESS LOANS. | Pass | Warehouse lending
Financing Receivable, Recorded Investment [Line Items]
Total loans	65,756,000	40,724,000
COMMERCIAL BUSINESS LOANS. | Watch | COMMERCIAL BUSINESS LOANS
Financing Receivable, Recorded Investment [Line Items]
Total loans	8,813,000	673,000
COMMERCIAL BUSINESS LOANS. | Watch | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total loans	8,813,000	0
COMMERCIAL BUSINESS LOANS. | Watch | Warehouse lending
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	673,000
COMMERCIAL BUSINESS LOANS. | Special Mention | COMMERCIAL BUSINESS LOANS
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	425,000
COMMERCIAL BUSINESS LOANS. | Special Mention | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	425,000
COMMERCIAL BUSINESS LOANS. | Special Mention | Warehouse lending
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
COMMERCIAL BUSINESS LOANS. | Substandard | COMMERCIAL BUSINESS LOANS
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,784,000	5,939,000
COMMERCIAL BUSINESS LOANS. | Substandard | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,784,000	5,939,000
COMMERCIAL BUSINESS LOANS. | Substandard | Warehouse lending
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
COMMERCIAL BUSINESS LOANS. | Doubtful | COMMERCIAL BUSINESS LOANS
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
COMMERCIAL BUSINESS LOANS. | Doubtful | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
COMMERCIAL BUSINESS LOANS. | Doubtful | Warehouse lending
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
COMMERCIAL BUSINESS LOANS. | Loss | COMMERCIAL BUSINESS LOANS
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
COMMERCIAL BUSINESS LOANS. | Loss | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
COMMERCIAL BUSINESS LOANS. | Loss | Warehouse lending
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 0	$ 0

Loans Receivable and Allowanc_9

Loans Receivable and Allowance For Loan Losses - Related Party Loans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Loans and Leases Receivable, Related Parties [Roll Forward]
Beginning balance	$ 655,000	$ 313,000
Additions	2,688,000	351,000
Repayments	(18,000)	(9,000)
Ending balance	3,325,000	655,000
Aggregate loan balances of extended credit	$ 3,600,000	$ 819,000

Servicing Rights - Narrative (D

Servicing Rights - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Off-balance Sheet Risks, Disclosure Information [Line Items]
Contractually specified servicing fees, late fees, and other ancillary fees	$ 2,400	$ 2,200
Mortgage servicing rights
Off-balance Sheet Risks, Disclosure Information [Line Items]
The unpaid principal balances of mortgage loans serviced	1,190,000	778,900
Fair market value of servicing rights' assets	14,600	8,600
Servicing Asset at Fair Value, Disposals	$ 0	$ 4,751

Servicing Rights - Servicing Ri

Servicing Rights - Servicing Rights (Details) - Mortgage servicing rights - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	$ 6,795	$ 8,459
Additions	5,971	5,075
Sales	0	(4,751)
Servicing rights amortized	(2,337)	(1,988)
Ending balance	$ 10,429	$ 6,795

Servicing Rights - Valuation As

Servicing Rights - Valuation Assumptions (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Off-balance Sheet Risks, Disclosure Information [Line Items]
Weighted average discount rate	9.50%	9.50%
Conditional prepayment rate ("CPR")	9.40%	10.90%
Weighted average life in years	7 years 8 months 12 days	6 years 8 months 12 days
Mortgage, commercial and consumer servicing rights
Off-balance Sheet Risks, Disclosure Information [Line Items]
Weighted average discount rate	9.60%	9.60%
Conditional prepayment rate ("CPR")	8.80%	10.90%

Servicing Rights - Changes in V

Servicing Rights - Changes in Valuation Assumptions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Off-balance Sheet Risks, Disclosure Information [Line Items]
Basis Points Drop in Note Rate, Assumption One	50.00%	50.00%
Basis Points Drop in Note Rate, Assumption Two	100.00%	100.00%
Conditional prepayment rate	9.40%	10.90%
Discount rate	9.50%	9.50%
Mortgage, commercial and consumer servicing rights
Off-balance Sheet Risks, Disclosure Information [Line Items]
Aggregate portfolio principal balance	$ 1,186,858	$ 775,093
Weighted average rate of note	4.30%	4.10%
Conditional prepayment rate	8.80%	10.90%
Conditional prepayment rate, 0.5% Adverse Change	11.60%	17.70%
Conditional prepayment rate, 1.0% Adverse Change	17.70%	24.50%
Fair value MSR	$ 14,218	$ 8,602
Fair value MSR, 0.5% Adverse Change	12,723	6,811
Fair value of MSR, 1.0% Adverse Change	$ 10,358	$ 5,614
Percentage of MSR	1.20%	1.10%
Percentage of MSR, 0.5% Adverse Change	1.10%	0.90%
Percentage of MSR, 1.0% Adverse Change	0.90%	0.70%
Discount rate	9.60%	9.60%
Discount rate, 0.5% Adverse Change	10.10%	10.10%
Discount rate, 1.0% Adverse Change	10.60%	10.60%
Fair value MSR, 0.5% Adverse Change	$ 13,912	$ 8,433
Fair value MSR, 1.0% Adverse Change	$ 13,617	$ 8,271
Percentage of MSR, 0.5% Adverse Change	1.20%	1.10%
Percentage of MSR, 1.0% Adverse Change	1.20%	1.10%

Premises and Equipment (Details

Premises and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	$ 43,031	$ 27,586
Less accumulated depreciation and amortization	(13,921)	(12,128)
Property, plant and equipment, net, total	29,110	15,458
Depreciation and amortization	1,800	1,600
Land
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	5,227	2,028
Buildings
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	16,772	8,611
Furniture, fixtures and equipment
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	12,039	10,105
Leasehold improvements
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	2,422	2,108
Building improvements
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	5,897	4,545
Projects in process
Property, Plant and Equipment [Line Items]
Premises and equipment, gross	$ 674	$ 189

Premises and Equipment - Operat

Premises and Equipment - Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2019	$ 1,312
2020	1,005
2021	855
2022	749
2023	390
Thereafter	1,228
Total	5,539
Rental expense of leased premises	$ 1,200	$ 1,100
Minimum
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Operating lease, renewal term	5 years
Maximum
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Operating lease, renewal term	10 years

Other Real Estate Owned - Activ

Other Real Estate Owned - Activity related to OREO (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Other Real Estate [Roll Forward]
Beginning balance	$ 0	$ 0
Additions	689	0
Ending balance	$ 689	$ 0

Other Real Estate Owned - Narra

Other Real Estate Owned - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Banking and Thrift [Abstract]
Net loans transferred to OREO	$ 689,000	$ 0
Other real estate owned holding costs (recovery)	$ 2,000

Deposits - Deposit Liabilities

Deposits - Deposit Liabilities (Details)	Dec. 31, 2018USD ($)	Nov. 15, 2018USD ($)	Dec. 31, 2017USD ($)	Jan. 22, 2016Office
Accounts, Notes, Loans and Financing Receivable [Line Items]
Noninterest-bearing checking	$ 221,107,000		$ 177,739,000
Interest-bearing checking	151,103,000		119,872,000
Savings	122,344,000		72,082,000
Money market	282,595,000		228,742,000
Certificates of deposit less than $100,000	243,193,000		111,489,000
Certificates of deposit of $100,000 through $250,000	154,095,000		77,934,000
Certificates of deposit of $250,000 and over	86,357,000		32,833,000
Escrow accounts related to mortgages serviced	13,425,000		9,151,000
Total deposits	1,274,219,000		829,842,000
Brokered certificates of deposit less than $100,000	116,700,000		59,300,000
Money market brokered deposits	1,000		6,500,000
Bank of America
Accounts, Notes, Loans and Financing Receivable [Line Items]
Branch purchase deposits	$ 120,000,000		$ 134,600,000
Number of owned bank branches acquired | Office				4
Anchor Bancorp
Accounts, Notes, Loans and Financing Receivable [Line Items]
Branch purchase deposits		$ 356,811,000

Deposits - Maturities of Time D

Deposits - Maturities of Time Deposits for Future Periods (Details) $ in Thousands	Dec. 31, 2018USD ($)
Banking and Thrift [Abstract]
Maturing in 2019	$ 290,822
Maturing in 2020	117,077
Maturing in 2021	37,277
Maturing in 2022	29,472
Maturing in 2023	8,997
Thereafter	0
Total	$ 483,645

Deposits - Interest Expense by

Deposits - Interest Expense by Deposit Category (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Banking and Thrift [Abstract]
Interest-bearing checking	$ 227	$ 128
Savings and money market	2,054	1,260
Certificates of deposit	5,040	2,532
Total	$ 7,321	$ 3,920

Deposits - Related Party Policy

Deposits - Related Party Policy (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Banking and Thrift [Abstract]
Related-party deposits	$ 6.2	$ 2.1

Debt - Narrative (Details)

Debt - Narrative (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2018	Dec. 31, 2017	Oct. 15, 2015
Debt Instrument [Line Items]
Federal home loan bank, advances, general debt obligations, maximum amount available, percentage of total assets (as a percent)		45.00%
Federal home loan bank, advances, general debt obligations, collateral pledged		$ 355,500,000
Federal home loan bank, advances, general debt obligations, unused capacity on pledged loans		120,000,000
Unsecured Fed Funds lines of credit		51,000,000
Unsecured Fed Funds, lines of credit, outstanding balance		0
Principal amount of subordinated debt				$ 10,000,000
Subordinated Note
Debt Instrument [Line Items]
Annual interest rate (as a percent)				6.50%
Contributions of proceeds from subordinated debt	$ 9,000,000
Federal Reserve Bank
Debt Instrument [Line Items]
Warehouse lines of credit		127,700,000	$ 99,100,000
Line of credit, outstanding balance		0	0
Federal Reserve Bank
Debt Instrument [Line Items]
Loans pledged as collateral		$ 265,200,000	$ 265,200,000

Debt - Advances on Borrowing Li

Debt - Advances on Borrowing Line (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Federal home loan bank, advances, general debt obligations	$ 137,149	$ 7,529
Securities Line
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Federal home loan bank, advances, general debt obligations	$ 137,149	$ 7,529
Securities Line | Minimum
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Federal Home Loan Bank, interest rates	1.15%	0.96%
Securities Line | Maximum
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Federal Home Loan Bank, interest rates	2.87%	1.73%

Debt - Maximum and Average Outs

Debt - Maximum and Average Outstanding, Weighted Average Interest Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Maximum balance:
Federal Home Loan Bank advances and Fed Funds	$ 180,025	$ 70,419
Federal Reserve Bank	0	1,000
Fed Funds lines of credit	21,016	17,501
Average balance:
Federal Home Loan Bank advances and Fed Funds	96,044	25,635
Fed Funds lines of credit	$ 0	$ 876
Weighted average interest rate:
Federal Home Loan Bank advances and Fed Funds (as a percent)	2.02%	1.26%
Federal Reserve Bank (as a percent)	0.00%	1.75%
Fed Funds lines of credit (as a percent)	1.93%	1.30%
Federal Reserve Bank, Advances, Activity for Year, Average Balance Outstanding	$ 5,286	$ 3
Subordinated note
Average balance:
Subordinated note	$ 10,000	$ 10,000
Weighted average interest rate:
Subordinated note (as a percent)	6.50%	6.50%
Subordinated note | Maximum
Maximum balance:
Subordinated note	$ 10,000	$ 10,000

Debt - Schedule of Federal Home

Debt - Schedule of Federal Home Loan Bank Advances Maturities Summary Due (Details) $ in Thousands	Dec. 31, 2018USD ($)
Federal Home Loan Bank, Advances, Fiscal Year Maturity [Abstract]
2019	$ 121,233
2020	12,284
2021	0
2022	0
2023	3,632
Total	$ 137,149
Federal Home Loan Bank, Advances, Maturities Summary, Average Interest Rate of Amounts Due [Abstract]
2019, Interest Rates (percent)	2.36%
2020, Interest Rates (percent)	2.46%
2021, Interest Rates (percent)	0.00%
2022, Interest Rates (percent)	0.00%
2023, Interest Rates (percent)	2.87%

Employee Benefits - Narrative (

Employee Benefits - Narrative (Details) - USD ($)	Jul. 09, 2012	Dec. 31, 2018	Dec. 31, 2017
Compensation and Retirement Disclosure [Abstract]
Number of hours of service required for participation in ESOP, per first 12 month period (in hours)		1000 hours
Vesting percentage after requisite service period is met (as a percent)		100.00%
Requisite service period (in years)		2 years
Number of hours per service period year (in hours)		1000 hours
Employee stock ownership plan (ESOP), debt structure, employer loan, amount	$ 2,600,000
Employee stock ownership plan (ESOP), weighted average purchase price of shares purchased (in dollars per share)	$ 10.17
Amortization period of ESOP loan		10 years
Employee stock ownership plan (ESOP), debt structure, employer loan, interest rate		2.30%
Employee stock ownership plan (ESOP), periodic installment payments from esop, amount paid		$ 269,000
Employee stock ownership plan (ESOP), interest payments from esop		26,000
ESOP compensation expense for allocated shares		$ 1,209,000	$ 1,424,000

Employee Benefits - Schedule of

Employee Benefits - Schedule of Shares Under ESOP (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Jul. 09, 2012
Employee Stock Ownership Plan (ESOP), Shares in ESOP [Abstract]
Allocated shares	176,809	153,049
Committed to be released shares	0	0
Unallocated shares	77,763	103,684
Total ESOP shares	254,572	256,733	259,210
Fair value of unallocated shares (in thousands)	$ 3,627	$ 5,696

Employee Benefits - 401(K) Plan

Employee Benefits - 401(K) Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Schedule of Defined Contribution Plans Disclosures [Line Items]
Defined contribution plan, minimum age requirement	18 years
Percentage vested in deferral contributions account	100.00%
Employer contributions	$ 917	$ 904
Contributions between 1% to 3%
Schedule of Defined Contribution Plans Disclosures [Line Items]
Employer matching percentage	100.00%
Contributions between 1% to 3% | Minimum
Schedule of Defined Contribution Plans Disclosures [Line Items]
Defined contribution plan, employee contribution (percent)	1.00%
Contributions between 1% to 3% | Maximum
Schedule of Defined Contribution Plans Disclosures [Line Items]
Defined contribution plan, employee contribution (percent)	3.00%
Contributions between 4% and 5%
Schedule of Defined Contribution Plans Disclosures [Line Items]
Employer matching percentage	50.00%
Contributions between 4% and 5% | Minimum
Schedule of Defined Contribution Plans Disclosures [Line Items]
Defined contribution plan, employee contribution (percent)	4.00%
Contributions between 4% and 5% | Maximum
Schedule of Defined Contribution Plans Disclosures [Line Items]
Defined contribution plan, employee contribution (percent)	5.00%

Income Taxes - Components of In

Income Taxes - Components of Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Provision for income taxes
Current	$ 3,455	$ 7,212
Deferred	(768)	(718)
Deferred income tax	768	(718)
Income Tax Expense (Benefit), Total	$ 4,223	$ 6,494

Income Taxes - Effective Income

Income Taxes - Effective Income Tax Rate (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Income tax provision at statutory rate	$ 6,000,000	$ 7,203,000
Tax exempt income	(129,000)	(218,000)
Nondeductible items resulting in increase in tax	279,000	0
Decrease in tax resulting from other items	(87,000)	(487,000)
Equity compensation	(571,000)	0
Executive compensation	135,000	0
Bargain purchase gain	(1,594,000)	0
Income tax rate differential	0	(396,000)
ESOP	190,000	392,000
Income Tax Expense (Benefit), Total	$ 4,223,000	$ 6,494,000
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Income tax provision at statutory rate	21.00%	35.00%
Tax exempt income	(0.50%)	(1.00%)
Nondeductible items resulting in increase in tax	1.00%
Decrease in tax resulting from other items	(0.30%)	(2.40%)
Equity compensation	(2.00%)
Executive compensation	0.50%
Bargain purchase gain	(5.60%)
Income tax rate differential	0.00%	(1.90%)
ESOP	0.70%	1.90%
Total	14.80%	31.60%

Income Taxes - Deferred Assets

Income Taxes - Deferred Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred Tax Assets
Net operating loss carryforward	$ 1,201	$ 0
Allowance for loan losses	3,077	1,912
Other real estate owned	127	0
Non-accrued loan interest	115	9
Restricted stock awards	54	0
Non-qualified stock options	71	0
Securities available-for-sale	405	130
Other	473	210
Total deferred tax assets	5,523	2,261
Deferred Tax Liabilities
Loan origination costs	(626)	(870)
Servicing rights	(2,241)	(1,461)
Prepaids	(166)	(52)
Stock dividend - FHLB stock	(73)	(1)
Property, plant, and equipment	(1,489)	(484)
Acquisition related costs	(1,289)	0
Total deferred tax liabilities	(5,884)	(2,868)
Net deferred tax liabilities	$ (361)	$ (607)

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
INCOME TAXES
Operating Loss Carryforwards	$ 5,600,000
Corporate federal income tax rate	21.00%	35.00%
Provisional income tax benefit		$ 396,000
Uncertain tax liabilities	$ 0	0
Recognized interest and penalties	$ 0	$ 0

Commitments and Contingencies -

Commitments and Contingencies - Commitment (Details) - Commitments to Extend Credit - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	$ 295,841	$ 284,887
REAL ESTATE LOANS | REAL ESTATE LOANS.
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	160,158	144,091
REAL ESTATE LOANS | Commercial
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	5,836	107
REAL ESTATE LOANS | Construction and development
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	76,889	73,321
REAL ESTATE LOANS | One-to-four-family (1)
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	35,714	37,336
REAL ESTATE LOANS | Home equity
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	41,204	32,889
REAL ESTATE LOANS | Commercial/Multi-family
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	515	438
CONSUMER LOANS | CONSUMER LOANS.
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	18,560	10,041
COMMERCIAL BUSINESS LOANS. | COMMERCIAL BUSINESS LOANS
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	117,123	130,755
COMMERCIAL BUSINESS LOANS. | Commercial and industrial
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	72,880	52,452
COMMERCIAL BUSINESS LOANS. | Warehouse lending
Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments	$ 44,243	$ 78,303

Commitments and Contingencies_2

Commitments and Contingencies - Narrative (Details)	1 Months Ended	12 Months Ended
	Mar. 31, 2008shares	Dec. 31, 2018USD ($)action$ / shares	Dec. 31, 2017USD ($)$ / shares
Loss Contingencies [Line Items]
Amount of loans sold to FHLB		$ 66,000,000
Federal Home Loan Bank, First Loss Account Established		741,000
Bank recourse obligation		$ 472,000
Bank recourse obligation, percentage of loans outstanding		0.71%
Reserve as a percentage of outstanding CE		10.00%
Reserve for loans sold		$ 218,000
Outstanding Delinquencies On Loans Sold to Federal Home Loan Bank		$ 0	$ 0
Pending material legal actions | action		0
Visa, Inc.
Loss Contingencies [Line Items]
Market value of stock (in dollars per share) | $ / shares		$ 131.94	$ 114.02
Visa, Inc. | Bank
Loss Contingencies [Line Items]
Common stock, conversion ratio	1.6298
Carrying value of stock		$ 0
Visa, Inc. | Bank | Class B Common Stock
Loss Contingencies [Line Items]
Number of shares received in an IPO | shares	7,158
Commitments to Extend Credit
Loss Contingencies [Line Items]
Reserve for estimated losses		299,000	$ 253,000
Guarantee on loans sold
Loss Contingencies [Line Items]
Reserve for estimated losses		$ 1,000,000	$ 1,000,000
Chief Executive Officer
Loss Contingencies [Line Items]
Severance agreement, period of base compensation used to calculate lump sum payment		24 months
CFO, Chief Lending Officer, COO, and two EVPs of Home Lending
Loss Contingencies [Line Items]
Severance agreement, period of base compensation used to calculate lump sum payment		12 months
Change of control agreement, prior notice required for cancellation		24 months
Change of control agreement, change in control payment, period before change in control		6 months
Change in control payment, period after change in control		12 months

Significant Concentration Of _2

Significant Concentration Of Credit Risk (Details)	12 Months Ended
	Dec. 31, 2018
Construction Land Development And Other Land Concentration [Member] | Credit Concentration Risk [Member] | Regulatory Capital [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	131.20%

Regulatory Capital - Compliance

Regulatory Capital - Compliance with Regulatory Capital Requirements under Banking Regulations (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2017	Jan. 01, 2016
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier 1 to Risk Weighted Assets, Capital Conservation Buffer, Phased in	1.875%		0.625%	0.625%
Common Equity Tier 1 to Risk Weighted Assets, Capital Conservation Buffer	2.50%
Total risk-based capital, Ratio	13.30%	15.70%
Tier 1 risk-based capital, Ratio	12.40%	14.50%
Tier 1 leverage capital, Ratio	12.10%	12.10%
CET 1 capital, Ratio	12.40%	14.50%
Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total risk-based capital, Amount	$ 188,472	$ 133,967
Total risk-based capital, Ratio	13.52%	16.25%
Total risk-based capital, For Capital Adequacy Purposes, Amount	$ 111,493	$ 65,965
Total risk-based capital, For Capital Adequacy Purposes, Ratio	8.00%	8.00%
Total risk-based capital, For Capital Adequacy with Capital Buffer, Amount	$ 137,694	$ 76,272
Total risk-based capital, For Capital Adequacy with Capital Buffer, Ratio	9.88%	9.25%
Total risk-based capital, To be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 139,366	$ 82,456
Total risk-based capital, To be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	10.00%	10.00%
Tier 1 risk-based capital, Amount	$ 175,824	$ 123,651
Tier 1 risk-based capital, Ratio	12.62%	15.00%
Tier 1 risk-based capital, For Capital Adequacy Purposes, Amount	$ 83,620	$ 49,474
Tier 1 risk-based capital, For Capital Adequacy Purposes, Ratio	6.00%	6.00%
Tier 1 risk-based capital, For Capital Adequacy with Capital Buffer, Amount	$ 109,820	$ 59,781
Tier 1 risk-based capital, For Capital Adequacy with Capital Buffer, Ratio	7.88%	7.25%
Tier 1 risk-based capital, To be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 111,493	$ 65,965
Tier 1 risk-based capital, To be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	8.00%	8.00%
Tier 1 leverage capital	$ 175,824	$ 123,651
Tier 1 leverage capital, Ratio	10.67%	12.61%
Tier 1 leverage capital, For Capital Adequacy Purposes, Amount	$ 65,884	$ 39,233
Tier 1 leverage capital, For Capital Adequacy Purposes, Ratio	4.00%	4.00%
Tier 1 leverage capital, For Capital Adequacy with Capital Buffer, Amount	$ 0	$ 0
Tier 1 leverage capital, To be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 82,355	$ 49,041
Tier 1 leverage capital, To be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	5.00%	5.00%
CET 1 capital, Amount	$ 175,824	$ 123,651
CET 1 capital, Ratio	12.62%	15.00%
CET 1 capital, For Capital Adequacy Purposes, Amount	$ 62,715	$ 37,105
CET 1 capital, For Capital Adequacy Purposes, Ratio	4.50%	4.50%
CET 1 capital, For Capital Adequacy with Capital Buffer, Amount	$ 88,846	$ 47,412
CET 1 capital, For Capital Adequacy with Capital Buffer, Ratio	6.38%	5.75%
CET 1 capital, To be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 90,588	$ 53,597
CET 1 capital, To be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	6.50%	6.50%

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Available for Sale Securities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	$ 97,205	$ 82,480
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	97,205	82,480
Fair Value, Measurements, Recurring | U.S. agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	15,887	9,115
Fair Value, Measurements, Recurring | Corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	6,865	7,026
Fair Value, Measurements, Recurring | Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	14,194	12,786
Fair Value, Measurements, Recurring | Mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	44,836	39,734
Fair Value, Measurements, Recurring | U.S. Small Business Administration securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	15,423	13,819
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	97,205	82,480
Fair Value, Measurements, Recurring | Level 2 | U.S. agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	15,887	9,115
Fair Value, Measurements, Recurring | Level 2 | Corporate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	6,865	7,026
Fair Value, Measurements, Recurring | Level 2 | Municipal bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	14,194	12,786
Fair Value, Measurements, Recurring | Level 2 | Mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	44,836	39,734
Fair Value, Measurements, Recurring | Level 2 | U.S. Small Business Administration securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	$ 15,423	$ 13,819

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Mortgage loans held for sale (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale, at fair value	$ 51,195	$ 53,463
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale, at fair value	$ 51,195	$ 53,463

Fair Value of Financial Instr_5

Fair Value of Financial Instruments - Interest Rate Lock Commitments Measured at Fair Value on Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest Rate Lock Commitments with Customers	$ 503	$ 726
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest Rate Lock Commitments with Customers	$ 503	$ 726

Fair Value of Financial Instr_6

Fair Value of Financial Instruments - Forward Sale Commitments with Investors (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individual Forward Sale Commitments with Investors	$ (574)	$ (14)
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individual Forward Sale Commitments with Investors	(540)	(65)
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Individual Forward Sale Commitments with Investors	$ (34)	$ 51

Fair Value of Financial Instr_7

Fair Value of Financial Instruments - Paired Off Commitments with Investors (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Paired Off Commitments, Asset, at Fair Value	$ (64)	$ 53
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Paired Off Commitments, Asset, at Fair Value	0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Paired Off Commitments, Asset, at Fair Value	(64)	53
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Paired Off Commitments, Asset, at Fair Value	$ 0	$ 0

Fair Value of Financial Instr_8

Fair Value of Financial Instruments - Impaired Loans and OREO (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned (OREO)	$ 689	$ 0
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired Loans, fair value	3,894	1,094
Fair Value, Measurements, Nonrecurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired Loans, fair value	0	0
Fair Value, Measurements, Nonrecurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired Loans, fair value	0	0
Fair Value, Measurements, Nonrecurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired Loans, fair value	3,894	1,094
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned (OREO)	689	0
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned (OREO)	0	0
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned (OREO)	0	0
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned (OREO)	$ 689	$ 0

Fair Value of Financial Instr_9

Fair Value of Financial Instruments - Discount Rate (Details)	Dec. 31, 2018item
Impaired Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale, Measurement Input [Extensible List]	fsbw:MeasurementInputDiscountAppliedToObtainedAppraisalMember
Debt Securities, Available-for-sale, Valuation Technique [Extensible List]	fsbw:FairValueOfUnderlyingCollateralMember
OREO
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale, Measurement Input [Extensible List]	fsbw:MeasurementInputDiscountAppliedToObtainedAppraisalMember
Debt Securities, Available-for-sale, Valuation Technique [Extensible List]	fsbw:FairValueOfUnderlyingCollateralMember
Fallout adjusted interest rate lock commitments with customers
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale, Measurement Input [Extensible List]	fsbw:MeasurementInputPullThroughExpectationsMember
Debt Securities, Available-for-sale, Valuation Technique [Extensible List]	fsbw:QuotedMarketPricesMember
Mandatory and best effort forward commitments with investors
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale, Measurement Input [Extensible List]	fsbw:MeasurementInputPullThroughExpectationsMember
Debt Securities, Available-for-sale, Valuation Technique [Extensible List]	fsbw:QuotedMarketPricesMember
Level 3 | Fair Value, Measurements, Recurring | Fallout adjusted interest rate lock commitments with customers | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale measurement input	80
Level 3 | Fair Value, Measurements, Recurring | Fallout adjusted interest rate lock commitments with customers | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale measurement input	99
Level 3 | Fair Value, Measurements, Recurring | Fallout adjusted interest rate lock commitments with customers | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale measurement input	95.2
Level 3 | Fair Value, Measurements, Recurring | Mandatory and best effort forward commitments with investors | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale measurement input	80
Level 3 | Fair Value, Measurements, Recurring | Mandatory and best effort forward commitments with investors | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale measurement input	99
Level 3 | Fair Value, Measurements, Recurring | Mandatory and best effort forward commitments with investors | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale measurement input	95.2
Level 3 | Fair Value, Measurements, Nonrecurring | Impaired Loans | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale measurement input	0
Level 3 | Fair Value, Measurements, Nonrecurring | Impaired Loans | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale measurement input	50
Level 3 | Fair Value, Measurements, Nonrecurring | Impaired Loans | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale measurement input	25
Level 3 | Fair Value, Measurements, Nonrecurring | OREO | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale measurement input	0
Level 3 | Fair Value, Measurements, Nonrecurring | OREO | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale measurement input	75
Level 3 | Fair Value, Measurements, Nonrecurring | OREO | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale measurement input	71.1

Fair Value of Financial Inst_10

Fair Value of Financial Instruments - Fair Value Level 3 on recurring basis (Details) - Level 3 - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fallout adjusted interest rate lock commitments with customers
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 726	$ 818
Purchases and Issuances	9,722	14,319
Sales and Settlements	(9,945)	(14,411)
Ending Balance	503	726
Net change in fair value for gains/(losses) relating to items held at end of period	(223)	(92)
Mandatory and best effort forward commitments with investors
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	51	177
Purchases and Issuances	850	141
Sales and Settlements	(935)	(267)
Ending Balance	(34)	51
Net change in fair value for gains/(losses) relating to items held at end of period	$ (85)	$ (126)

Fair Value of Financial Inst_11

Fair Value of Financial Instruments - Fair Value By Balance Sheet Grouping (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financial Assets
Certificates of deposit at other financial institutions	$ 22,074	$ 18,108
Securities available-for-sale, at fair value	97,205	82,480
Fair Value, Measurements, Recurring
Financial Assets
Securities available-for-sale, at fair value	97,205	82,480
Loans held for sale, at fair value	51,195	53,463
Paired off commitments with investors	(64)	53
Fair Value, Measurements, Nonrecurring
Financial Assets
Impaired Loans, fair value	3,894	1,094
Level 1 | Fair Value, Measurements, Recurring
Financial Assets
Paired off commitments with investors	0	0
Level 1 | Fair Value, Measurements, Nonrecurring
Financial Assets
Impaired Loans, fair value	0	0
Level 2 | Fair Value, Measurements, Recurring
Financial Assets
Securities available-for-sale, at fair value	97,205	82,480
Loans held for sale, at fair value	51,195	53,463
Paired off commitments with investors	(64)	53
Level 2 | Fair Value, Measurements, Nonrecurring
Financial Assets
Impaired Loans, fair value	0	0
Level 3 | Fair Value, Measurements, Recurring
Financial Assets
Paired off commitments with investors	0	0
Level 3 | Fair Value, Measurements, Nonrecurring
Financial Assets
Impaired Loans, fair value	3,894	1,094
Carrying Amount | Level 1
Financial Assets
Cash and cash equivalents	32,779	18,915
Certificates of deposit at other financial institutions	22,074	18,108
Carrying Amount | Level 2
Financial Assets
Securities available-for-sale, at fair value	97,205	82,480
Loans held for sale, at fair value	51,195	53,463
FHLB stock, at cost	9,887	2,871
Accrued interest receivable	5,761	3,566
Paired off commitments with investors		53
Financial Liabilities
Deposits	1,274,219	829,842
Borrowings	137,149	7,529
Subordinated note, net	9,865	9,845
Accrued interest payable	344	214
Paired Off Commitments with Investors	64
Individual forward sale commitments with investors, financial liability	540	65
Carrying Amount | Level 3
Financial Assets
Loans receivable, gross	1,326,238	773,445
Servicing rights, held at lower of cost or fair value	10,429	6,795
Fair value interest rate locks with customers	503	726
Individual forward sale commitments with investors		51
Financial Liabilities
Individual forward sale commitments with investors, financial liability	34
Fair Value | Level 1
Financial Assets
Cash and cash equivalents	32,779	18,915
Certificates of deposit at other financial institutions	22,074	18,108
Fair Value | Level 2
Financial Assets
Securities available-for-sale, at fair value	97,205	82,480
Loans held for sale, at fair value	51,195	53,463
FHLB stock, at cost	9,887	2,871
Accrued interest receivable	5,761	3,566
Paired off commitments with investors		53
Financial Liabilities
Deposits	1,261,096	838,087
Borrowings	136,873	7,498
Subordinated note, net	10,242	10,741
Accrued interest payable	344	214
Paired Off Commitments with Investors	64
Individual forward sale commitments with investors, financial liability	540	65
Fair Value | Level 3
Financial Assets
Loans receivable, gross	1,320,341	780,551
Servicing rights, held at lower of cost or fair value	14,593	8,608
Fair value interest rate locks with customers	503	726
Individual forward sale commitments with investors		$ 51
Financial Liabilities
Individual forward sale commitments with investors, financial liability	$ 34

Earnings Per Share - Schedule o

Earnings Per Share - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Net Income	$ 24,347	$ 14,085
Basic weighted average common shares outstanding	3,698,623	3,094,586
Dilutive shares (in shares)	171,166	197,114
Denominator for diluted earnings per share- weighted average common shares outstanding (shares)	3,869,789	3,291,700
Basic earnings per share (in dollars per share)	$ 6.58	$ 4.55
Diluted earnings per share (in dollars per share)	$ 6.29	$ 4.28
Potentially dilutive securities excluded from EPS	11,326
Options outstanding	290,104	256,237

Derivatives (Details)

Derivatives (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Margin Cash Collateral	$ 460,000	$ 75,000
Derivatives, fair value changes, gain on sale of loans	(702,000)	2,300,000
Not Designated as Hedging Instrument | Fallout adjusted interest rate lock commitments with customers
Derivative [Line Items]
Notional	29,432,000	31,951,000
Fair Value, Asset	503,000	726,000
Not Designated as Hedging Instrument | Mandatory and best effort forward commitments with investors
Derivative [Line Items]
Notional	24,776,000	12,505,000
Fair Value, Asset		51,000
Fair Value, Liability	34,000
Not Designated as Hedging Instrument | Forward TBA mortgage-backed securities
Derivative [Line Items]
Notional	51,500,000	66,500,000
Fair Value, Liability	540,000	65,000
Not Designated as Hedging Instrument | TBA mortgage-backed securities forward sales paired off with investors
Derivative [Line Items]
Notional	6,500,000	36,500,000
Fair Value, Asset		$ 53,000
Fair Value, Liability	$ 64,000

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) - USD ($)	Aug. 15, 2018	Jan. 01, 2016	May 08, 2014	Sep. 30, 2013	Dec. 31, 2018	Dec. 31, 2017	May 17, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award contractual life					10 years
Granted (in shares)					100,000	0
Expected forfeiture rate over contractual term					3.1
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period					10 years
Remaining weighted-average vesting period					6 years 9 months 29 days
Total intrinsic value of options exercised					$ 2,453,314	$ 1,100,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option, fair value assumption, expected life					6 years 6 months
Unrecognized compensation cost, nonvested awards					$ 1,300,000
Unrecognized compensation cost, period for recognition					4 years 4 months 24 days
Fair Value Assumptions
Dividend yield					0.95%
Expected volatility					18.80%
Risk-free interest rate					2.77%
Expected term					6 years 6 months
Weighted-average grant date fair value per option granted					$ 13.22
Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost, nonvested awards					$ 1,500,000
Unrecognized compensation cost, period for recognition					4 years 3 months 18 days
Total fair value of shares vested					$ 1,100,000	1,400,000
2013 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense					767,000	634,000
Income tax benefit from share-based compensation expense					$ 161,000	$ 222,000
Shares available for grant					6,013
Remaining weighted-average vesting period						6 years 4 months 10 days
2013 Equity Incentive Plan | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option, fair value assumption, expected life					6 years 6 months
Fair Value Assumptions
Expected term					6 years 6 months
2013 Equity Incentive Plan | Equity Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)				324,013
Market value of stock (in dollars per share)			$ 16.89
Granted (in shares)				322,000
2013 Equity Incentive Plan | Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)				129,605
Market value of stock (in dollars per share)		$ 26	$ 16.89
Shares		4,500	125,105
Equity Incentive Plan 2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant					387,000
Equity Incentive Plan 2018 [Member] | Equity Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares	100,000
Equity Incentive Plan 2018 [Member] | Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares	25,000
Equity Incentive Plan 2018 [Member] | Equity Option And Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)							650,000
Market value of stock (in dollars per share)	$ 58.60
Equity Incentive Plans 2013 And 2018 [Member] | Equity Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period					5 years
Annual award vesting percentage					20.00%
Award contractual life					10 years
Expiration period					10 years
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period					10 years
Maximum | Equity Incentive Plan 2018 [Member] | Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)							163,000

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Option Activity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Shares
Outstanding, beginning balance (in shares)	256,237
Granted, Shares	100,000	0
Less exercised (in shares)	66,133
Outstanding, ending balance (in shares)	290,104	256,237
Expected to vest, assuming a 0.31% annual forfeiture rate (in shares)	289,226
Exercisable (in shares)	129,304
Weighted-Average Exercise Price
Outstanding, beginning balance (in dollars per share)	$ 16.89
Granted (in dollars per share)	58.60
Less exercised (in dollars per share)	16.89
Outstanding, ending balance (in dollars per share)	31.27	$ 16.89
Expected to vest, assuming a 0.31% annual forfeiture rate (in dollars per share)	31.19
Exercisable (in dollars per share)	$ 16.89
Weighted-Average Remaining Contractual Term In Years
Outstanding, ending balance	6 years 9 months 29 days
Expected to vest, assuming a 0.31% annual forfeiture rate, Weighted Average Remaining Contractual Term	6 years 9 months 26 days
Exercisable	5 years 4 months 10 days
Aggregate Intrinsic Value
Beginning balance	$ 9,655,010
Less exercised	2,453,314	$ 1,100,000
Ending balance	4,940,803	$ 9,655,010
Expected to vest, assuming a 0.31% annual forfeiture rate	4,939,069
Exercisable	$ 3,360,611
2013 Equity Incentive Plan
Shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expected Forfeiture Rate	0.31%
Weighted-Average Remaining Contractual Term In Years
Outstanding, ending balance		6 years 4 months 10 days

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Awards (Details) - Restricted stock awards	12 Months Ended
	Dec. 31, 2018$ / sharesshares
Shares
Nonvested, Beginning balance (in shares) | shares	36,842
Granted (shares) | shares	25,000
Less vested (in shares) | shares	18,421
Nonvested, Ending balance (in shares) | shares	43,421
Weighted-Average Grant-Date Fair Value Per Share
Nonvested, Beginning balance (in dollars per share) | $ / shares	$ 17.63
Granted (in dollars per share) | $ / shares	58.60
Less vested (in dollars per share) | $ / shares	17.63
Nonvested, Ending balance (in dollars per share) | $ / shares	$ 41.22

Business Segments - Narrative (

Business Segments - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)segmentitem	Dec. 31, 2017USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | segment	2
Deposits	$ 1,274,219	$ 829,842
Commercial and Consumer Banking
Segment Reporting Information [Line Items]
Deposits	$ 1,270,000	$ 829,800
Commercial and Consumer Banking | Retail Deposit | Pacific Northwest
Segment Reporting Information [Line Items]
Number of bank branches | item	21

Business Segments - Segment Fin

Business Segments - Segment Financial Results (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)item	Dec. 31, 2017USD ($)item
Segment Reporting Information [Line Items]
Net interest income	$ 52,098	$ 41,248
Provision for loan losses	(1,540)	(750)
Noninterest income	26,850	24,074
Noninterest expense	(48,838)	(43,993)
INCOME BEFORE PROVISION FOR INCOME TAXES	28,570	20,579
Provision for income taxes	(4,223)	(6,494)
Assets	1,621,644	981,783
NET INCOME	24,347	14,085
Total average assets at quarter end	$ 1,174,713	$ 923,581
FTEs | item	424	326
Home Lending
Segment Reporting Information [Line Items]
Net interest income	$ 3,324	$ 2,587
Provision for loan losses	(224)	(287)
Noninterest income	14,025	18,973
Noninterest expense	(15,894)	(17,052)
INCOME BEFORE PROVISION FOR INCOME TAXES	1,231	4,221
Provision for income taxes	(182)	(1,332)
Assets	246,280	220,353
NET INCOME	1,049	2,889
Total average assets at quarter end	$ 229,661	$ 203,379
FTEs | item	115	119
Commercial and Consumer Banking
Segment Reporting Information [Line Items]
Net interest income	$ 48,774	$ 38,661
Provision for loan losses	(1,316)	(463)
Noninterest income	12,825	5,101
Noninterest expense	(32,944)	(26,941)
INCOME BEFORE PROVISION FOR INCOME TAXES	27,339	16,358
Provision for income taxes	(4,041)	(5,162)
Assets	1,375,364	761,430
NET INCOME	23,298	11,196
Total average assets at quarter end	$ 945,052	$ 720,202
FTEs | item	309	207

Revenue From Contracts With C_2

Revenue From Contracts With Customers (Details)	12 Months Ended
	Dec. 31, 2018USD ($)
Not in scope noninterest income.	$ 25,100,000
Deposit Fees [Member] | Commercial and Consumer Banking
Net Revenue	2,500,000
Debit Card Interchange Fees [Member] | Commercial and Consumer Banking
Net Revenue	1,200,000
Non Sufficient Funds Fees [Member] | Commercial and Consumer Banking
Net Revenue	$ 561,000

Goodwill And Other Intangible_3

Goodwill And Other Intangible Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 2,312,000	$ 2,312,000
Goodwill, Impairment Loss	0	0
Finite-Lived Intangible Assets, Net [Abstract]
Finite-Lived Intangible Assets, Gross	7,490,000	2,239,000	$ 2,239,000
Finite-Lived Intangible Assets, Accumulated Amortization	(1,273,000)	(922,000)	(522,000)
Amortization	(351,000)	(400,000)
Finite-Lived Intangible Assets, Net	6,217,000	1,317,000	1,717,000
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2019	760,000
2020	706,000
2021	691,000
2022	691,000
2023	691,000
Thereafter	2,678,000
Total	6,217,000	$ 1,317,000	$ 1,717,000
Bank of America
Finite-Lived Intangible Assets, Net [Abstract]
Amortization	$ (307,000)
Finite-Lived Intangible Asset, Useful Life	9 years
Anchor Bancorp
Finite-Lived Intangible Assets, Net [Abstract]
Amortization	$ (44,000)
Additions as a result of the Anchor Acquistion Gross	5,251,000
Additions as a result of the Anchor Acquistion Net	$ 5,207,000
Finite-Lived Intangible Asset, Useful Life	10 years