Parent Company Only Condensed Financial Statements - Condensed Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Cash	$ 167,256	$ 196,552	$ 153,323	$ 198,802
Total assets	7,333,791	5,645,662
Subordinated debentures and notes	141,258	118,156
Notes payable	34,286	2,000
Shareholders' equity	867,185	603,804	548,573	387,098
Total liabilities and shareholders' equity	7,333,791	5,645,662
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Cash	21,955	6,369	$ 9,977	$ 52,245
Other assets	37,905	30,287
Total assets	1,047,614	725,710
Subordinated debentures and notes	141,258	118,156
Notes payable	34,286	2,000
Accounts payable and other liabilities	4,885	1,750
Shareholders' equity	867,185	603,804
Total liabilities and shareholders' equity	1,047,614	725,710
Enterprise Bank and Trust [Member] | Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Investments	977,959	681,742
Nonbank Subsidiaries [Member] | Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Investments	$ 9,795	$ 7,312