Parent Company Only Condensed Financial Statements - Condensed Balance Sheets (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]
Cash	$ 100,696	$ 210,569	$ 116,370	$ 188,143
Total assets	3,277,003us-gaap_Assets	3,170,197us-gaap_Assets
Subordinated debentures	56,807us-gaap_SubordinatedDebt	62,581us-gaap_SubordinatedDebt
Notes payable	5,700us-gaap_NotesPayableToBank	10,500us-gaap_NotesPayableToBank
Shareholders' equity	316,241us-gaap_StockholdersEquity	279,705us-gaap_StockholdersEquity	235,745us-gaap_StockholdersEquity	239,565us-gaap_StockholdersEquity
Total liabilities and shareholders' equity	3,277,003	3,170,197
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Cash	14,532	15,969	8,080	21,247
Other assets	19,223	18,537
Total assets	379,522	353,652
Subordinated debentures	56,807	62,581
Notes payable	5,700	10,500
Accounts payable and other liabilities	774	866
Shareholders' equity	316,241	279,705
Total liabilities and shareholders' equity	379,522	353,652
Enterprise Bank and Trust [Member] \| Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Investments	344,995	318,721
Enterprise Financial CDE LLC [Member] \| Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Investments	$ 772	$ 425

Sum of the carrying values as of the balance sheet date of obligations incurred through that date, including liabilities incurred and payable to vendors for goods and services received, taxes, interest, rent and utilities, compensation costs, payroll taxes and fringe benefits (other than pension and postretirement obligations), contractual rights and obligations, and statutory obligations.

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Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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

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Total investments in (A) an entity in which the entity has significant influence, but does not have control, (B) subsidiaries that are not required to be consolidated and are accounted for using the equity and or cost method, and (C) an entity in which the reporting entity shares control of the entity with another party or group. Includes long-term advances receivable from a party that is affiliated with the reporting entity by means of direct or indirect ownership.

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Amount of liabilities and equity items, including the portion of equity attributable to noncontrolling interests, if any.

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Including the current and noncurrent portions, the carrying value as of the balance sheet date of notes payable to banks, excluding mortgage notes, initially due beyond one year or beyond the operating cycle if longer.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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