Stock-Based Compensation (Details) (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012 Employee Stock Incentive Plan [Member] Y	Mar. 31, 2011 Employee Stock Incentive Plan [Member]	Mar. 31, 2012 State Bancorp's Stock Incentive Plan [Member] Y	Dec. 31, 2011 State Bancorp's Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares, authorized			7,400,000
Number of shares, awarded during the period			540,000	165
Number of shares, available for grant			6,300,000
Incentive stock option's maximum term to exercise, years			10
Stock-based compensation expense	$ 1,443,000	$ 682,000	$ 1,400,000	$ 701,000
Stock-based compensation amortization expense unrecognized			$ 7,000,000
Maximum vesting period, years			2
Assumed number of shares, outstanding						356,000
Outstanding stock options, weighted average exercise price					$ 17.41
Outstanding stock options, weighted average remaining term, in years					3
Number of shares, exercisable					321,000