Summary of Significant Accounting Policies (Policies)	3 Months Ended
Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of presentation	Basis of presentation The accounting and reporting policies of the Company and its subsidiaries conform to U.S. generally accepted accounting principles (“GAAP”) and general practice within the banking industry. The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from those estimates. Material estimates which are particularly susceptible to significant change in the near term relate to the fair value of investment securities and other-than-temporary impairment of securities, the determination of the allowance for loan losses and valuation of other real estate owned. For further information with respect to significant accounting policies followed by the Company in the preparation of its consolidated financial statements, refer to the Company’s Annual Report on Form 10-K for the year ended December 31, 2016. The consolidated financial statements include the accounts of the Company and Centrue Bank. Intercompany balances and transactions have been eliminated in consolidation and certain 2016 amounts have been reclassified to conform to the 2017 presentation. The annualized results of operations during the three months ended March 31, 2017 are not necessarily indicative of the results expected for the year ending December 31, 2017. All financial information in the following tables is in thousands (000s), except share and per share data. In the opinion of management, all normal and recurring adjustments which are necessary to fairly present the results for the interim periods presented have been included.
Recent Accounting Pronouncements	Recent Accounting Pronouncements The Company has elected to comply with new and amended accounting pronouncements in the same manner as a private company under its status as an emerging growth company, as such the effective dates presented below are the dates the accounting standards become effective for the Company. In March 2017, the FASB amended existing guidance (ASU 2017-08) to shorten the amortization period for certain callable debt securities held at a premium. Specifically, the amendments require the premium to be amortized to the earliest call date. The amendments do not require an accounting change for securities held at a discount; the discount continues to be amortized to maturity. The amended guidance is effective for fiscal years, and interim periods within those years, beginning after December 15, 2019, and interim periods within fiscal years beginning after December 15, 2020 with early adoption permitted. The amendments are to be applied on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. Management is currently in the process of evaluating the impact of the amended guidance on its Consolidated Financial Statements. In August 2016, the FASB issued amended guidance (ASU 2016-15) to clarify the classification of certain items with an entity’s statements of cash flows. These items include debt prepayment or extinguishment costs, settlement of zero-coupon debt instruments, contingent consideration payments made after a business combination, proceeds from the settlement of insurance claims, proceeds from the settlement of BOLI policies, distributions received from equity method investees, and beneficial interests in securitization transactions. The amended guidance also specifies how to address classification of cash receipts and payments that have aspects of more than one class of cash flows. The amended guidance is effective for fiscal years beginning after December 15, 2018, and interim periods within fiscal years beginning after December 15, 2019, with early adoption permitted, and is to be applied on a retrospective basis unless it is impractical to do so. Management is currently in the process of evaluating the impact of the amended guidance on its Consolidated Financial Statements. In June 2016 the FASB issued accounting standards update 2016-13 Financial Instruments - Credit Losses, commonly referred to as CECL. The provisions of the update eliminate the probable initial recognition threshold under current GAAP which requires reserves to be based on an incurred loss methodology. Under CECL reserves required for financial assets measured at amortized cost will reflect an organization’s estimate of all expected credit losses over the contractual term of the financial asset and thereby require the use of reasonable and supportable forecasts to estimate future credit losses. Because CECL encompasses all financial assets carried at amortized cost, the requirement that reserves be established based on an organization’s reasonable and supportable estimate of expected credit losses extends to held to maturity (HTM) debt securities. Under the provisions of the update credit losses recognized on available for sale (AFS) debt securities will be presented as an allowance as opposed to a write-down. In addition, CECL will modify the accounting for purchased loans, with credit deterioration since origination, so that reserves are established at the date of acquisition for purchased loans. Under current GAAP a purchased loan’s contractual balance is adjusted to fair value through a credit discount and no reserve is recorded on the purchased loan upon acquisition. Since under CECL reserves will be established for purchased loans at the time of acquisition the accounting for purchased loans is made more comparable to the accounting for originated loans. Finally, increased disclosure requirements under CECL oblige organizations to present the currently required credit quality disclosures disaggregated by the year of origination or vintage. FASB expects that the evaluation of underwriting standards and credit quality trends by financial statement users will be enhanced with the additional vintage disclosures. For the Company, the ASU on credit losses will take effect for fiscal years beginning after December 15, 2020. and interim periods within fiscal years beginning after December 15, 2021. Management is in the process of developing an implementation plan for CECL and estimating the impact on the Company’s financial position, results of operations and cash flows as well as its required disclosures. In March 2016, the FASB issued an update (ASU No. 2016-09, Stock Compensation: Improvements to Employee Share-Based Payment Accounting.) The guidance in this update affects any entity that issues share-based payment awards to its employees and is intended to simplify several aspects of the accounting for share-based payment awards including income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The amendments in this update are effective for annual periods beginning after December 15, 2017, and interim periods within annual periods beginning after December 15, 2018. Early adoption is permitted. The adoption of this standard is not expected to have a material effect on the Company's results of operations or financial position. In February 2016, the FASB issued an update (ASU No. 2016-02, Leases) creating FASB Topic 842, Leases. The guidance is intended to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and requiring more disclosures related to leasing transactions. The amendments in this update are effective for fiscal years beginning after December 15, 2019, and interim periods within fiscal years beginning after December 15, 2020. Early adoption is permitted. Management is currently evaluating the impact on the consolidated financial statements and related disclosures.

Recent Accounting Pronouncements

The Company has elected to comply with new and amended accounting pronouncements in the same manner as a private company under its status as an emerging growth company, as such the effective dates presented below are the dates the accounting standards become effective for the Company.

In March 2017, the FASB amended existing guidance (ASU 2017-08) to shorten the amortization period for certain callable debt securities held at a premium. Specifically, the amendments require the premium to be amortized to the earliest call date. The amendments do not require an accounting change for securities held at a discount; the discount continues to be amortized to maturity. The amended guidance is effective for fiscal years, and interim periods within those years, beginning after December 15, 2019, and interim periods within fiscal years beginning after December 15, 2020 with early adoption permitted. The amendments are to be applied on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. Management is currently in the process of evaluating the impact of the amended guidance on its Consolidated Financial Statements.

In August 2016, the FASB issued amended guidance (ASU 2016-15) to clarify the classification of certain items with an entity’s statements of cash flows. These items include debt prepayment or extinguishment costs, settlement of zero-coupon debt instruments, contingent consideration payments made after a business combination, proceeds from the settlement of insurance claims, proceeds from the settlement of BOLI policies, distributions received from equity method investees, and beneficial interests in securitization transactions. The amended guidance also specifies how to address classification of cash receipts and payments that have aspects of more than one class of cash flows. The amended guidance is effective for fiscal years beginning after December 15, 2018, and interim periods within fiscal years beginning after December 15, 2019, with early adoption permitted, and is to be applied on a retrospective basis unless it is impractical to do so. Management is currently in the process of evaluating the impact of the amended guidance on its Consolidated Financial Statements.

In June 2016 the FASB issued accounting standards update 2016-13 Financial Instruments - Credit Losses, commonly referred to as CECL. The provisions of the update eliminate the probable initial recognition threshold under current GAAP which requires reserves to be based on an incurred loss methodology. Under CECL reserves required for financial assets measured at amortized cost will reflect an organization’s estimate of all expected credit losses over the contractual term of the financial asset and thereby require the use of reasonable and supportable forecasts to estimate future credit losses. Because CECL encompasses all financial assets carried at amortized cost, the requirement that reserves be established based on an organization’s reasonable and supportable estimate of expected credit losses extends to held to maturity (HTM) debt securities. Under the provisions of the update credit losses recognized on available for sale (AFS) debt securities will be presented as an allowance as opposed to a write-down. In addition, CECL will modify the accounting for purchased loans, with credit deterioration since origination, so that reserves are established at the date of acquisition for purchased loans. Under current GAAP a purchased loan’s contractual balance is adjusted to fair value through a credit discount and no reserve is recorded on the purchased loan upon acquisition. Since under CECL reserves will be established for purchased loans at the time of acquisition the accounting for purchased loans is made more comparable to the accounting for originated loans. Finally, increased disclosure requirements under CECL oblige organizations to present the currently required credit quality disclosures disaggregated by the year of origination or vintage. FASB expects that the evaluation of underwriting standards and credit quality trends by financial statement users will be enhanced with the additional vintage disclosures. For the Company, the ASU on credit losses will take effect for fiscal years beginning after December 15, 2020. and interim periods within fiscal years beginning after December 15, 2021. Management is in the process of developing an implementation plan for CECL and estimating the impact on the Company’s financial position, results of operations and cash flows as well as its required disclosures.

In March 2016, the FASB issued an update (ASU No. 2016-09, Stock Compensation: Improvements to Employee Share-Based Payment Accounting.) The guidance in this update affects any entity that issues share-based payment awards to its employees and is intended to simplify several aspects of the accounting for share-based payment awards including income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The amendments in this update are effective for annual periods beginning after December 15, 2017, and interim periods within annual periods beginning after December 15, 2018. Early adoption is permitted. The adoption of this standard is not expected to have a material effect on the Company's results of operations or financial position.

In February 2016, the FASB issued an update (ASU No. 2016-02, Leases) creating FASB Topic 842, Leases. The guidance is intended to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and requiring more disclosures related to leasing transactions. The amendments in this update are effective for fiscal years beginning after December 15, 2019, and interim periods within fiscal years beginning after December 15, 2020. Early adoption is permitted. Management is currently evaluating the impact on the consolidated financial statements and related disclosures.