Borrowed Funds (Details Textual) (USD $)	3 Months Ended	12 Months Ended		12 Months Ended		3 Months Ended	1 Months Ended		3 Months Ended			3 Months Ended		3 Months Ended			3 Months Ended							3 Months Ended		3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Trust II Preferred Securities [Member]	Dec. 31, 2012 Trust III Preferred Securities [Member]	Mar. 31, 2013 Trust III Preferred Securities [Member]	Mar. 31, 2013 Trust IV Preferred Securities [Member]	Jan. 24, 2013 ESB Capital Trust II (Trust II) [Member]	Jul. 23, 2008 ESB Capital Trust II (Trust II) [Member]	Mar. 31, 2013 ESB Capital Trust II (Trust II) [Member]	Dec. 31, 2008 ESB Capital Trust II (Trust II) [Member]	Apr. 10, 2003 ESB Capital Trust II (Trust II) [Member]	Mar. 31, 2013 ESB Capital Trust IV (Trust IV) [Member]	Feb. 10, 2005 ESB Capital Trust IV (Trust IV) [Member]	Mar. 31, 2013 ESB Statutory Trust (Trust III) [Member]	Mar. 15, 2013 ESB Statutory Trust (Trust III) [Member]	Dec. 17, 2003 ESB Statutory Trust (Trust III) [Member]	Mar. 31, 2013 Structured advances [Member]	Mar. 31, 2013 Repurchase agreements [Member]	Dec. 31, 2012 Repurchase agreements [Member]	Mar. 31, 2013 Variable rate [Member] ESB Capital Trust II (Trust II) [Member]	Apr. 10, 2003 Variable rate [Member] ESB Capital Trust II (Trust II) [Member]	Mar. 31, 2013 Variable rate [Member] ESB Statutory Trust (Trust III) [Member]	Dec. 17, 2003 Variable rate [Member] ESB Statutory Trust (Trust III) [Member]	Mar. 31, 2013 Structured REPOs [Member]	Dec. 31, 2012 Structured REPOs [Member]	Mar. 31, 2013 Citigroup [Member]	Dec. 31, 2012 Citigroup [Member]	Mar. 31, 2013 Barclays Capital [Member]	Dec. 31, 2012 Barclays Capital [Member]	Mar. 31, 2013 Credit Suisse [Member]	Dec. 31, 2012 Credit Suisse [Member]	Mar. 31, 2013 Morgan Stanley [Member]	Dec. 31, 2012 Morgan Stanley [Member]	Jan. 24, 2013 WesBanco Loan [Member]
Borrowed Funds (Textual) [Abstract]
FHLB advances	$ 257,268,000	$ 213,232,000															$ 257,300,000	$ 178,000,000	$ 268,000,000
Structured advances																	50,000,000
Structured REPO's																		178,000,000
Period of fixed interest rate																		5 years
Notional amount of imbedded caps	50,000,000
Debt instrument variable rates basis																	50.0 million in structured advances in with imbedded caps at various strike rates based on the 3 month LIBOR rate.
Repurchase agreements with flexible interest rates																								20,000,000
REPO interest rate term																								3.75% based on the 3 month LIBOR rate
Repurchase agreements with fixed interest rate																								25,000,000
Securities available for sale; cost	1,045,225,000	1,065,447,000																						206,700,000	297,800,000
REPO's with other banks																										75,000,000	115,000,000	30,000,000	40,000,000	53,000,000	83,000,000	20,000,000	30,000,000
Risk related to repurchase agreement amount																										16,400,000		8,200,000		16,200,000		2,100,000
Weighted average maturity																										22 months		35 months		35 months		15 months
Preferred securities													35,000,000								10,000,000		5,000,000
Liquidation preference per share											$ 1,000					$ 1,000
Redeemed preferred securities							5,100,000	5,000,000							5,100,000
Preferred securities									5,000,000
Purchase of common securities									310,000			1,100,000		155,000
Proceeds from bank loan							10,000,000	14,000,000
Loans Payable										9,000,000
Interest rate										5.55%
Subordinated debt												36,100,000								10,300,000		5,200,000
Maturity date of subordinated debt									Apr. 24, 2033			Feb. 10, 2035		Dec. 17, 2033
Preferred securities fixed interest rate												6.03% for six years
Preferred securities variable interest rate									LIBOR plus 3.25%			Three month LIBOR plus 1.82%		LIBOR Index plus 2.95%
Maturity year of preferred securities												30 years
Maturity date of subordinated debt start date range									Apr. 24, 2008			Feb. 10, 2011		Dec. 17, 2008
Maturity date of subordinated debt end date range									Apr. 24, 2033			Feb. 10, 2035		Dec. 17, 2033
Fixed interest rate						6.03%																												3.75%
Unamortized deferred debt issuance costs									0			0		0
Proceeds from bank loan	10,000,000
Preferred securities interest rate			3.25%		2.95%	1.82%
Maturity of redemption of subordinated debt				90 days		90 days
Borrowed Funds (Additional Textual) [Abstract]
Market value of the securities	220,900,000	318,900,000
Repurchase agreements, maturities	Greater than 90 days	Greater than 90 days
Average borrowings under REPO	224,700,000
Maximum month-end outstanding amount	$ 258,000,000
Subordinated debt redemption description	The Company may redeem in whole, but not in part, the subordinated debt at any time within 90 days following the occurrence of such event
LIBOR Rate	3 months
Strike rate of imbedded caps	3.75%
Interest rate on structured REPO's with imbedded caps	less than zero
Preferred securities maturity period	Six years