Summary of Significant Accounting Policies	9 Months Ended
Sep. 30, 2013
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES The significant accounting policies used by Enterprise Financial Services Corp (the “Company” or “Enterprise”) in the preparation of the condensed consolidated financial statements are summarized below: Business and Consolidation Enterprise is a financial holding company that provides a full range of banking and wealth management services to individuals and corporate customers located in the St. Louis, Kansas City and Phoenix metropolitan markets through its banking subsidiary, Enterprise Bank & Trust (the “Bank”). Operating results for the three and nine months ended September 30, 2013 are not necessarily indicative of the results that may be expected for any other interim period or for the year ending December 31, 2013. For further information, refer to the consolidated financial statements and footnotes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2012. Basis of Financial Statement Presentation The condensed consolidated financial statements of the Company and its subsidiaries have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. They do not include all information and footnotes required by U.S. GAAP for annual financial statements. The condensed consolidated financial statements include the accounts of the Company and its subsidiaries, all of which are wholly owned. All intercompany accounts and transactions have been eliminated. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. The Company has adopted the new accounting guidance surrounding comprehensive income by presenting a separate Statement of Comprehensive Income. The Statement of Comprehensive Income includes the amount and the related tax impact that have been reclassified from accumulated other comprehensive income to net income. The reclassification adjustment for unrealized gain on sale of securities included in net income has been recorded through the gain on sale of investment securities line item, within noninterest income, in the Company's Condensed Consolidated Statements of Operations.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

The significant accounting policies used by Enterprise Financial Services Corp (the “Company” or “Enterprise”) in the preparation of the condensed consolidated financial statements are summarized below:

Business and Consolidation

Enterprise is a financial holding company that provides a full range of banking and wealth management services to individuals and corporate customers located in the St. Louis, Kansas City and Phoenix metropolitan markets through its banking subsidiary, Enterprise Bank & Trust (the “Bank”).

Operating results for the three and nine months ended September 30, 2013 are not necessarily indicative of the results that may be expected for any other interim period or for the year ending December 31, 2013. For further information, refer to the consolidated financial statements and footnotes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2012.

Basis of Financial Statement Presentation

The condensed consolidated financial statements of the Company and its subsidiaries have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. They do not include all information and footnotes required by U.S. GAAP for annual financial statements. The condensed consolidated financial statements include the accounts of the Company and its subsidiaries, all of which are wholly owned. All intercompany accounts and transactions have been eliminated. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included.

The Company has adopted the new accounting guidance surrounding comprehensive income by presenting a separate Statement of Comprehensive Income. The Statement of Comprehensive Income includes the amount and the related tax impact that have been reclassified from accumulated other comprehensive income to net income. The reclassification adjustment for unrealized gain on sale of securities included in net income has been recorded through the gain on sale of investment securities line item, within noninterest income, in the Company's Condensed Consolidated Statements of Operations.