Junior Subordinated Debentures Issued to Capital Trusts - Additional Information (Detail) (USD $)	12 Months Ended			0 Months Ended			12 Months Ended			12 Months Ended				12 Months Ended				12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Oct. 25, 2013 Trust Preferred Securities Subject to Mandatory Redemption [Member]	Jul. 26, 2013 VNB Capital Trust I [Member]	Dec. 31, 2012 VNB Capital Trust I [Member] Trust Preferred Securities Subject to Mandatory Redemption [Member]	Dec. 31, 2012 VNB Capital Trust I [Member] Subordinated Debentures Subject to Mandatory Redemption [Member]	Dec. 31, 2013 GCB Capital Trust III [Member] Trust Preferred Securities Subject to Mandatory Redemption [Member]	Dec. 31, 2012 GCB Capital Trust III [Member] Trust Preferred Securities Subject to Mandatory Redemption [Member]	Dec. 31, 2013 GCB Capital Trust III [Member] Subordinated Debentures Subject to Mandatory Redemption [Member]	Dec. 31, 2012 GCB Capital Trust III [Member] Subordinated Debentures Subject to Mandatory Redemption [Member]	Dec. 31, 2013 State Bancorp Capital Trust I [Member] Trust Preferred Securities Subject to Mandatory Redemption [Member]	Dec. 31, 2012 State Bancorp Capital Trust I [Member] Trust Preferred Securities Subject to Mandatory Redemption [Member]	Dec. 31, 2013 State Bancorp Capital Trust I [Member] Subordinated Debentures Subject to Mandatory Redemption [Member]	Dec. 31, 2012 State Bancorp Capital Trust I [Member] Subordinated Debentures Subject to Mandatory Redemption [Member]	Dec. 31, 2013 State Bancorp Capital Trust II [Member] Trust Preferred Securities Subject to Mandatory Redemption [Member]	Dec. 31, 2012 State Bancorp Capital Trust II [Member] Trust Preferred Securities Subject to Mandatory Redemption [Member]	Dec. 31, 2013 State Bancorp Capital Trust II [Member] Subordinated Debentures Subject to Mandatory Redemption [Member]	Dec. 31, 2012 State Bancorp Capital Trust II [Member] Subordinated Debentures Subject to Mandatory Redemption [Member]
Subordinated Borrowing [Line Items]
Contractual principal amounts redeemed of junior subordinated debentures					$ 15,400,000
Annual interest rate					7.75%			6.96%		6.96%
Redemption of related outstanding trust preferred securities				131,300,000
Net trading gains and losses included in non-cash credits	881,000	2,600,000	1,300,000
Junior subordinated debentures issued to capital trusts	41,089,000	188,522,000					147,600,000			24,982,000	25,100,000			8,424,000	8,300,000			7,683,000	7,600,000
Contractual principal balances							146,700,000			24,743,000	24,700,000			10,310,000	10,300,000			10,310,000	10,300,000
Face value						$ 142,300,000		$ 24,000,000	$ 24,000,000			$ 10,000,000	$ 10,000,000			$ 10,000,000	$ 10,000,000
Maximum allowable period of interest deferment	5 years
Percentage of securities issued by capital trusts	75.00%