Parent Company Only Condensed Financial Statements - Condensed Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Cash	$ 94,157	$ 100,696	$ 210,569	$ 116,370
Total assets	3,608,483	3,277,003
Subordinated debentures	56,807	56,807
Notes payable	0	5,700
Shareholders' equity	350,829	316,241	279,705	235,745
Total liabilities and shareholders' equity	3,608,483	3,277,003
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Cash	12,032	14,532	$ 15,969	$ 8,080
Other assets	20,357	19,223
Total assets	407,991	379,522
Subordinated debentures	56,807	56,807
Notes payable	0	5,700
Accounts payable and other liabilities	355	774
Shareholders' equity	350,829	316,241
Total liabilities and shareholders' equity	407,991	379,522
Enterprise Bank and Trust [Member] | Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Investments	374,092	344,995
Enterprise Financial CDE LLC [Member] | Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Investments	$ 1,510	$ 772