SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Significant Accounting Policies [Line Items]
Cash and cash equivalents, interest-bearing deposits in other financial institutions	$ 2,000,000,000	$ 1,900,000,000
Cash and cash equivalents, interest-bearing deposits in other financial institutions, Federal Reserve Bank of New York	1,200,000,000	1,200,000,000
Cash and cash equivalents, federal funds sold	5,800,000	870,000
Cash and cash equivalents, outstanding reverse repurchase agreements	646,500,000	550,000,000
Minimum amount required to be maintained as reserves with the Federal Reserve Bank of New York	115,600,000	100,900,000
Other real estate owned	155,967,000	90,478,000
Other real estate owned, covered by FDIC loss sharing agreements	71,400,000	62,412,000
Depreciation and amortization	23,535,000	20,112,000	19,982,000
Bank-owned life insurance	768,996,000	742,481,000
Bank-owned life insurance income	$ 28,384,000	$ 28,015,000	$ 27,406,000
Building
Significant Accounting Policies [Line Items]
Premises, furniture, fixtures, and equipment, estimated useful lives (in years)	20
Furniture, Fixtures and Equipment
Significant Accounting Policies [Line Items]
Premises, furniture, fixtures, and equipment, estimated useful lives, minimum (in years)	3
Premises, furniture, fixtures, and equipment, estimated useful lives, maximum (in years)	10
Core deposit intangibles
Significant Accounting Policies [Line Items]
Core deposit intangible, estimated useful lives, maximum (in years)	10
Options and Restricted Stock
Significant Accounting Policies [Line Items]
Shares available for grant	3,010,058