3.19.1 html 375 257 1 false 65 0 false 4 false false R1.htm 000 - Document - Document And Entity Information Sheet http://ottawasavings.com/20190331/role/statement-document-and-entity-information Document And Entity Information Cover 1 false false R2.htm 001 - Statement - Consolidated Balance Sheets (Current Period Unaudited) Sheet http://ottawasavings.com/20190331/role/statement-consolidated-balance-sheets-current-period-unaudited Consolidated Balance Sheets (Current Period Unaudited) Statements 2 false false R3.htm 002 - Statement - Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) Sheet http://ottawasavings.com/20190331/role/statement-consolidated-balance-sheets-current-period-unaudited-parentheticals Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) Statements 3 false false R4.htm 003 - Statement - Consolidated Statements of Income (Unaudited) Sheet http://ottawasavings.com/20190331/role/statement-consolidated-statements-of-income-unaudited Consolidated Statements of Income (Unaudited) Statements 4 false false R5.htm 004 - Statement - Consolidated Statements of Comprehensive Income (Unaudited) Sheet http://ottawasavings.com/20190331/role/statement-consolidated-statements-of-comprehensive-income-unaudited Consolidated Statements of Comprehensive Income (Unaudited) Statements 5 false false R6.htm 005 - Statement - Consolidated Statements of Stockholders' Equity (Unaudited) Sheet http://ottawasavings.com/20190331/role/statement-consolidated-statements-of-stockholders-equity-unaudited Consolidated Statements of Stockholders' Equity (Unaudited) Statements 6 false false R7.htm 006 - Statement - Consolidated Statements of Stockholders' Equity (Unaudited) (Parentheticals) Sheet http://ottawasavings.com/20190331/role/statement-consolidated-statements-of-stockholders-equity-unaudited-parentheticals Consolidated Statements of Stockholders' Equity (Unaudited) (Parentheticals) Statements 7 false false R8.htm 007 - Statement - Consolidated Statements of Cash Flows (Unaudited) Sheet http://ottawasavings.com/20190331/role/statement-consolidated-statements-of-cash-flows-unaudited Consolidated Statements of Cash Flows (Unaudited) Statements 8 false false R9.htm 008 - Disclosure - Note 1 - Nature of Business Sheet http://ottawasavings.com/20190331/role/statement-note-1-nature-of-business Note 1 - Nature of Business Notes 9 false false R10.htm 009 - Disclosure - Note 2 - Basis of Presentation Sheet http://ottawasavings.com/20190331/role/statement-note-2-basis-of-presentation Note 2 - Basis of Presentation Notes 10 false false R11.htm 010 - Disclosure - Note 3 - Use of Estimates Sheet http://ottawasavings.com/20190331/role/statement-note-3-use-of-estimates Note 3 - Use of Estimates Notes 11 false false R12.htm 011 - Disclosure - Note 4 - Critical Accounting Policies Sheet http://ottawasavings.com/20190331/role/statement-note-4-critical-accounting-policies Note 4 - Critical Accounting Policies Notes 12 false false R13.htm 012 - Disclosure - Note 5 - Earnings Per Share Sheet http://ottawasavings.com/20190331/role/statement-note-5-earnings-per-share Note 5 - Earnings Per Share Notes 13 false false R14.htm 013 - Disclosure - Note 6 - Employee Stock Ownership Plan Sheet http://ottawasavings.com/20190331/role/statement-note-6-employee-stock-ownership-plan Note 6 - Employee Stock Ownership Plan Notes 14 false false R15.htm 014 - Disclosure - Note 7 - Investment Securities Sheet http://ottawasavings.com/20190331/role/statement-note-7-investment-securities Note 7 - Investment Securities Notes 15 false false R16.htm 015 - Disclosure - Note 8 - Loans and Allowance for Credit Losses Sheet http://ottawasavings.com/20190331/role/statement-note-8-loans-and-allowance-for-credit-losses Note 8 - Loans and Allowance for Credit Losses Notes 16 false false R17.htm 016 - Disclosure - Note 9 - Stock Compensation Sheet http://ottawasavings.com/20190331/role/statement-note-9-stock-compensation Note 9 - Stock Compensation Notes 17 false false R18.htm 017 - Disclosure - Note 10 - Recent Accounting Developments Sheet http://ottawasavings.com/20190331/role/statement-note-10-recent-accounting-developments Note 10 - Recent Accounting Developments Notes 18 false false R19.htm 018 - Disclosure - Note 11 - Borrowings Sheet http://ottawasavings.com/20190331/role/statement-note-11-borrowings Note 11 - Borrowings Notes 19 false false R20.htm 019 - Disclosure - Note 12 - Fair Value Measurement and Disclosure Sheet http://ottawasavings.com/20190331/role/statement-note-12-fair-value-measurement-and-disclosure Note 12 - Fair Value Measurement and Disclosure Notes 20 false false R21.htm 020 - Disclosure - Significant Accounting Policies (Policies) Sheet http://ottawasavings.com/20190331/role/statement-significant-accounting-policies-policies Significant Accounting Policies (Policies) Policies http://ottawasavings.com/20190331/role/statement-note-4-critical-accounting-policies 21 false false R22.htm 021 - Disclosure - Note 5 - Earnings Per Share (Tables) Sheet http://ottawasavings.com/20190331/role/statement-note-5-earnings-per-share-tables Note 5 - Earnings Per Share (Tables) Tables http://ottawasavings.com/20190331/role/statement-note-5-earnings-per-share 22 false false R23.htm 022 - Disclosure - Note 6 - Employee Stock Ownership Plan (Tables) Sheet http://ottawasavings.com/20190331/role/statement-note-6-employee-stock-ownership-plan-tables Note 6 - Employee Stock Ownership Plan (Tables) Tables http://ottawasavings.com/20190331/role/statement-note-6-employee-stock-ownership-plan 23 false false R24.htm 023 - Disclosure - Note 7 - Investment Securities (Tables) Sheet http://ottawasavings.com/20190331/role/statement-note-7-investment-securities-tables Note 7 - Investment Securities (Tables) Tables http://ottawasavings.com/20190331/role/statement-note-7-investment-securities 24 false false R25.htm 024 - Disclosure - Note 8 - Loans and Allowance for Credit Losses (Tables) Sheet http://ottawasavings.com/20190331/role/statement-note-8-loans-and-allowance-for-credit-losses-tables Note 8 - Loans and Allowance for Credit Losses (Tables) Tables http://ottawasavings.com/20190331/role/statement-note-8-loans-and-allowance-for-credit-losses 25 false false R26.htm 025 - Disclosure - Note 11 - Borrowings (Tables) Sheet http://ottawasavings.com/20190331/role/statement-note-11-borrowings-tables Note 11 - Borrowings (Tables) Tables http://ottawasavings.com/20190331/role/statement-note-11-borrowings 26 false false R27.htm 026 - Disclosure - Note 12 - Fair Value Measurement and Disclosure (Tables) Sheet http://ottawasavings.com/20190331/role/statement-note-12-fair-value-measurement-and-disclosure-tables Note 12 - Fair Value Measurement and Disclosure (Tables) Tables http://ottawasavings.com/20190331/role/statement-note-12-fair-value-measurement-and-disclosure 27 false false R28.htm 027 - Disclosure - Note 5 - Earnings Per Share - Earnings Per Share (Details) Sheet http://ottawasavings.com/20190331/role/statement-note-5-earnings-per-share-earnings-per-share-details Note 5 - Earnings Per Share - Earnings Per Share (Details) Details 28 false false R29.htm 028 - Disclosure - Note 6 - Employee Stock Ownership Plan (Details Textual) Sheet http://ottawasavings.com/20190331/role/statement-note-6-employee-stock-ownership-plan-details-textual Note 6 - Employee Stock Ownership Plan (Details Textual) Details http://ottawasavings.com/20190331/role/statement-note-6-employee-stock-ownership-plan-tables 29 false false R30.htm 029 - Disclosure - Note 6 - Employee Stock Ownership Plan - Employee Stock Ownership Plan (Details) Sheet http://ottawasavings.com/20190331/role/statement-note-6-employee-stock-ownership-plan-employee-stock-ownership-plan-details Note 6 - Employee Stock Ownership Plan - Employee Stock Ownership Plan (Details) Details 30 false false R31.htm 030 - Disclosure - Note 7 - Investment Securities (Details Textual) Sheet http://ottawasavings.com/20190331/role/statement-note-7-investment-securities-details-textual Note 7 - Investment Securities (Details Textual) Details http://ottawasavings.com/20190331/role/statement-note-7-investment-securities-tables 31 false false R32.htm 031 - Disclosure - Note 7 - Investment Securities - Amortized Cost and Fair Values of Securities (Details) Sheet http://ottawasavings.com/20190331/role/statement-note-7-investment-securities-amortized-cost-and-fair-values-of-securities-details Note 7 - Investment Securities - Amortized Cost and Fair Values of Securities (Details) Details 32 false false R33.htm 032 - Disclosure - Note 7 - Investment Securities - Securities by Contractual Maturity (Details) Sheet http://ottawasavings.com/20190331/role/statement-note-7-investment-securities-securities-by-contractual-maturity-details Note 7 - Investment Securities - Securities by Contractual Maturity (Details) Details 33 false false R34.htm 033 - Disclosure - Note 7 - Investment Securities - Securities With Gross Unrealized Losses (Details) Sheet http://ottawasavings.com/20190331/role/statement-note-7-investment-securities-securities-with-gross-unrealized-losses-details Note 7 - Investment Securities - Securities With Gross Unrealized Losses (Details) Details 34 false false R35.htm 034 - Disclosure - Note 8 - Loans and Allowance for Credit Losses (Details Textual) Sheet http://ottawasavings.com/20190331/role/statement-note-8-loans-and-allowance-for-credit-losses-details-textual Note 8 - Loans and Allowance for Credit Losses (Details Textual) Details http://ottawasavings.com/20190331/role/statement-note-8-loans-and-allowance-for-credit-losses-tables 35 false false R36.htm 035 - Disclosure - Note 8 - Loans and Allowance for Credit Losses - Components of Loans, Net of Deferred Loan Costs (Fees) (Details) Sheet http://ottawasavings.com/20190331/role/statement-note-8-loans-and-allowance-for-credit-losses-components-of-loans-net-of-deferred-loan-costs-fees-details Note 8 - Loans and Allowance for Credit Losses - Components of Loans, Net of Deferred Loan Costs (Fees) (Details) Details 36 false false R37.htm 036 - Disclosure - Note 8 - Loans and Allowance for Credit Losses - Purchases of Loans Receivable (Details) Sheet http://ottawasavings.com/20190331/role/statement-note-8-loans-and-allowance-for-credit-losses-purchases-of-loans-receivable-details Note 8 - Loans and Allowance for Credit Losses - Purchases of Loans Receivable (Details) Details 37 false false R38.htm 037 - Disclosure - Note 8 - Loans and Allowance for Credit Losses - Net (Charge-offs) Recoveries (Details) Sheet http://ottawasavings.com/20190331/role/statement-note-8-loans-and-allowance-for-credit-losses-net-chargeoffs-recoveries-details Note 8 - Loans and Allowance for Credit Losses - Net (Charge-offs) Recoveries (Details) Details http://ottawasavings.com/20190331/role/statement-note-8-loans-and-allowance-for-credit-losses-tables 38 false false R39.htm 038 - Disclosure - Note 8 - Loans and Allowance for Credit Losses - Recorded Investment in Loans and the Related Allowances (Details) Sheet http://ottawasavings.com/20190331/role/statement-note-8-loans-and-allowance-for-credit-losses-recorded-investment-in-loans-and-the-related-allowances-details Note 8 - Loans and Allowance for Credit Losses - Recorded Investment in Loans and the Related Allowances (Details) Details 39 false false R40.htm 039 - Disclosure - Note 8 - Loans and Allowance for Credit Losses - Loans Individually Evaluated for Impairment (Details) Sheet http://ottawasavings.com/20190331/role/statement-note-8-loans-and-allowance-for-credit-losses-loans-individually-evaluated-for-impairment-details Note 8 - Loans and Allowance for Credit Losses - Loans Individually Evaluated for Impairment (Details) Details 40 false false R41.htm 040 - Disclosure - Note 8 - Loans and Allowance for Credit Losses - Nonaccrual Loans and Loans Past Due Over 90 Days (Details) Sheet http://ottawasavings.com/20190331/role/statement-note-8-loans-and-allowance-for-credit-losses-nonaccrual-loans-and-loans-past-due-over-90-days-details Note 8 - Loans and Allowance for Credit Losses - Nonaccrual Loans and Loans Past Due Over 90 Days (Details) Details 41 false false R42.htm 041 - Disclosure - Note 8 - Loans and Allowance for Credit Losses - Aging of the Recorded Investment in Loans (Details) Sheet http://ottawasavings.com/20190331/role/statement-note-8-loans-and-allowance-for-credit-losses-aging-of-the-recorded-investment-in-loans-details Note 8 - Loans and Allowance for Credit Losses - Aging of the Recorded Investment in Loans (Details) Details 42 false false R43.htm 042 - Disclosure - Note 8 - Loans and Allowance for Credit Losses - Loans by Risk Category (Details) Sheet http://ottawasavings.com/20190331/role/statement-note-8-loans-and-allowance-for-credit-losses-loans-by-risk-category-details Note 8 - Loans and Allowance for Credit Losses - Loans by Risk Category (Details) Details 43 false false R44.htm 043 - Disclosure - Note 9 - Stock Compensation (Details Textual) Sheet http://ottawasavings.com/20190331/role/statement-note-9-stock-compensation-details-textual Note 9 - Stock Compensation (Details Textual) Details http://ottawasavings.com/20190331/role/statement-note-9-stock-compensation 44 false false R45.htm 044 - Disclosure - Note 11 - Borrowings - Outstanding Advances (Details) Sheet http://ottawasavings.com/20190331/role/statement-note-11-borrowings-outstanding-advances-details Note 11 - Borrowings - Outstanding Advances (Details) Details 45 false false R46.htm 045 - Disclosure - Note 11 - Borrowings - Outstanding Advances (Details) (Parentheticals) Sheet http://ottawasavings.com/20190331/role/statement-note-11-borrowings-outstanding-advances-details-parentheticals Note 11 - Borrowings - Outstanding Advances (Details) (Parentheticals) Details 46 false false R47.htm 046 - Disclosure - Note 12 - Fair Value Measurement and Disclosure (Details Textual) Sheet http://ottawasavings.com/20190331/role/statement-note-12-fair-value-measurement-and-disclosure-details-textual Note 12 - Fair Value Measurement and Disclosure (Details Textual) Details http://ottawasavings.com/20190331/role/statement-note-12-fair-value-measurement-and-disclosure-tables 47 false false R48.htm 047 - Disclosure - Note 12 - Fair Value Measurement and Disclosure - Assets Measured at Fair Value on a Recurring Basis (Details) Sheet http://ottawasavings.com/20190331/role/statement-note-12-fair-value-measurement-and-disclosure-assets-measured-at-fair-value-on-a-recurring-basis-details Note 12 - Fair Value Measurement and Disclosure - Assets Measured at Fair Value on a Recurring Basis (Details) Details 48 false false R49.htm 048 - Disclosure - Note 12 - Fair Value Measurement and Disclosure - Assets Measured at Fair Value on a Non-recurring Basis (Details) Sheet http://ottawasavings.com/20190331/role/statement-note-12-fair-value-measurement-and-disclosure-assets-measured-at-fair-value-on-a-nonrecurring-basis-details Note 12 - Fair Value Measurement and Disclosure - Assets Measured at Fair Value on a Non-recurring Basis (Details) Details 49 false false R50.htm 049 - Disclosure - Note 12 - Fair Value Measurement and Disclosure - Quantitative Information About Assets Measured at Fair Value (Details) Sheet http://ottawasavings.com/20190331/role/statement-note-12-fair-value-measurement-and-disclosure-quantitative-information-about-assets-measured-at-fair-value-details Note 12 - Fair Value Measurement and Disclosure - Quantitative Information About Assets Measured at Fair Value (Details) Details 50 false false R51.htm 050 - Disclosure - Note 12 - Fair Value Measurement and Disclosure - Estimated Fair Values of Financial Instruments (Details) Sheet http://ottawasavings.com/20190331/role/statement-note-12-fair-value-measurement-and-disclosure-estimated-fair-values-of-financial-instruments-details Note 12 - Fair Value Measurement and Disclosure - Estimated Fair Values of Financial Instruments (Details) Details 51 false false All Reports Book All Reports ottw-20190331.xml ottw-20190331.xsd ottw-20190331_cal.xml ottw-20190331_def.xml ottw-20190331_lab.xml ottw-20190331_pre.xml http://fasb.org/us-gaap/2019-01-31 http://fasb.org/srt/2019-01-31 http://xbrl.sec.gov/dei/2018-01-31 true true