Preferred Stock and Common Stock Warrants-Common Stock Warrants (Details) (Common Stock [Member], USD $) In Millions, unless otherwise specified	0 Months Ended
Dec. 19, 2008
Common Stock [Member]
Class of Warrant or Right [Line Items]
Aggregate investment by U.S. Treasury	$ 35.0

Preferred Stock and Class of Warrant or Right, Cash Received on Issuance

No definition available.

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Namespace Prefix:	efsc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration