Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)	12 Months Ended					12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Core Deposits [Member]	Mar. 31, 2012 Core Deposits [Member] State Bancorp, Inc. [Member]	Dec. 31, 2013 Other [Member]	Dec. 31, 2013 Residential Mortgage Loans [Member]	Dec. 31, 2012 Residential Mortgage Loans [Member]	Dec. 31, 2011 Residential Mortgage Loans [Member]	Dec. 31, 2013 SBA Loans [Member]	Dec. 31, 2012 SBA Loans [Member]	Dec. 31, 2011 SBA Loans [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill, Other Changes	$ 0
Goodwill impairment	0	0	0
Weighted average amortization period, years				11 years		17 years
Core deposits intangibles from acquisition					8,100,000
Impairment of core deposits and intangibles	0	0	0
Aggregate principal balances of mortgage loans serviced							2,500,000,000	1,800,000,000	1,300,000
Total amount of loans serviced by bank										28,400,000	30,400,000	33,100,000
Amortization expense - other intangible assets	$ 8,300,000	$ 9,800,000	$ 9,300,000