Subordinated Debentures (Details) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Subordinated Borrowing [Line Items]
Subordinated debentures	$ 62,581,000	$ 62,581,000	$ 85,081,000
Investments trust preferred securities	2,600,000	2,600,000
Subordinated debentures	20,000,000	20,000,000
Stock Issued During Period, Shares, Conversion of Convertible Securities		1,176,470	0	0
Debt Conversion, Converted Instrument, Shares Issued		25,060
Induced Conversion of Convertible Debt Expense		400,000
Repayment of Subordinated Notes		2,000,000
Repayments of Long-term Debt	500,000	1,200,000	300,000	0
Debt Instrument, Interest Rate, Stated Percentage	10.00%	10.00%
EFSC Capital Trust VIII [Member]
Subordinated Borrowing [Line Items]
Conversion price (usd per share)	$ 17.37	$ 17.37
Trust preferred securities [Member]
Subordinated Borrowing [Line Items]
Subordinated debentures	62,581,000	62,581,000	82,581,000
Trust preferred securities [Member] | EFSC Clayco Statutory Trust I [Member]
Subordinated Borrowing [Line Items]
Subordinated debentures	3,196,000	3,196,000	3,196,000
Maturity date		Dec. 17, 2033
Call date		Dec. 17, 2008
Description of variable rate		3 Month LIBOR
Floating interest rate	2.85%	2.85%
Trust preferred securities [Member] | EFSC Capital Trust II [Member]
Subordinated Borrowing [Line Items]
Subordinated debentures	5,155,000	5,155,000	5,155,000
Maturity date		Jun. 17, 2034
Call date		Jun. 17, 2009
Description of variable rate		3 Month LIBOR
Floating interest rate	2.65%	2.65%
Trust preferred securities [Member] | EFSC Statutory Trust III [Member]
Subordinated Borrowing [Line Items]
Subordinated debentures	11,341,000	11,341,000	11,341,000
Maturity date		Dec. 15, 2034
Call date		Dec. 15, 2009
Description of variable rate		3 Month LIBOR
Floating interest rate	1.97%	1.97%
Trust preferred securities [Member] | EFSC Clayco Statutory Trust II [Member]
Subordinated Borrowing [Line Items]
Subordinated debentures	4,124,000	4,124,000	4,124,000
Maturity date		Sep. 15, 2035
Call date		Sep. 15, 2010
Description of variable rate		3 Month LIBOR
Floating interest rate	1.83%	1.83%
Trust preferred securities [Member] | EFSC Statutory Trust IV [Member]
Subordinated Borrowing [Line Items]
Subordinated debentures	10,310,000	10,310,000	10,310,000
Maturity date		Dec. 15, 2035
Call date		Dec. 15, 2010
Description of variable rate		3 Month LIBOR
Floating interest rate	1.44%	1.44%
Trust preferred securities [Member] | EFSC Statutory Trust V [Member]
Subordinated Borrowing [Line Items]
Subordinated debentures	4,124,000	4,124,000	4,124,000
Maturity date		Sep. 15, 2036
Call date		Sep. 15, 2011
Description of variable rate		3 Month LIBOR
Floating interest rate	1.60%	1.60%
Trust preferred securities [Member] | EFSC Capital Trust VI [Member]
Subordinated Borrowing [Line Items]
Subordinated debentures	14,433,000	14,433,000	14,433,000
Maturity date		Mar. 30, 2037
Call date		Mar. 30, 2012
Description of variable rate		3 Month LIBOR
Floating interest rate	1.60%	1.60%
Trust preferred securities [Member] | EFSC Capital Trust VII [Member]
Subordinated Borrowing [Line Items]
Subordinated debentures	4,124,000	4,124,000	4,124,000
Maturity date		Dec. 15, 2037
Call date		Dec. 15, 2012
Description of variable rate		3 Month LIBOR
Floating interest rate	2.25%	2.25%
Trust preferred securities [Member] | EFSC Capital Trust VIII [Member]
Subordinated Borrowing [Line Items]
Subordinated debentures	5,774,000	5,774,000	25,774,000
Maturity date		Dec. 15, 2038
Call date		Dec. 15, 2013
Fixed interest rate		9.00%
Subordinated notes [Member]
Subordinated Borrowing [Line Items]
Subordinated debentures	0	0	2,500,000
Maturity date		Oct. 01, 2018
Call date		Oct. 01, 2013
Fixed interest rate		10.00%
Entity controlled by a former director [Member] | EFSC Capital Trust VIII [Member]
Subordinated Borrowing [Line Items]
Convertible subordinated debt controlled by a former member of the Company's board of directors	$ 5,000,000	$ 5,000,000