Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Significant Accounting Policies [Line Items]
Cash and cash equivalents, interest-bearing deposits in other financial institutions	$ 644,600,000	$ 2,400,000,000
Cash and cash equivalents, interest-bearing deposits in other financial institutions, Federal Reserve Bank of New York	208,000,000	1,700,000,000
Cash and cash equivalents, federal funds sold	4,800,000	8,900,000
Cash and cash equivalents, outstanding reverse repurchase agreements	250,000,000	549,700,000
Minimum amount required to be maintained as total reserves with the Federal Reserve Bank of New York	133,700,000	134,300,000
Depreciation and amortization	28,092,000	25,471,000	23,535,000
Bank-owned life insurance	893,522,000	867,250,000
Bank-owned life insurance income	29,938,000	30,502,000	28,384,000
Purchase of bank-owned life insurance policy	0	80,000,000
Other real estate owned	108,869,000	74,415,000
Other real estate owned, covered by FDIC loss sharing agreements	$ 37,477,000	$ 45,115,000
Building
Significant Accounting Policies [Line Items]
Premises, furniture, fixtures, and equipment, estimated useful lives (in years)	20 years
Options and Restricted Stock
Significant Accounting Policies [Line Items]
Shares available for grant	16,757,551
Two Thousand Twelve Incentive Plan
Significant Accounting Policies [Line Items]
Shares transferred	1,030,673
Maximum | Furniture and Fixtures
Significant Accounting Policies [Line Items]
Premises, furniture, fixtures, and equipment, estimated useful lives (in years)	10 years
Maximum | Equipment
Significant Accounting Policies [Line Items]
Premises, furniture, fixtures, and equipment, estimated useful lives (in years)	10 years
Minimum | Furniture and Fixtures
Significant Accounting Policies [Line Items]
Premises, furniture, fixtures, and equipment, estimated useful lives (in years)	3 years
Minimum | Equipment
Significant Accounting Policies [Line Items]
Premises, furniture, fixtures, and equipment, estimated useful lives (in years)	3 years
Core deposit intangibles | Maximum
Significant Accounting Policies [Line Items]
Core deposit intangible, estimated useful lives (in years)	10 years