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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Fair value portion of arrangements with third parties, including, but not limited to, operating lease arrangement and arrangement in which the entity has agreed to expend funds to procure goods or services, or has agreed to commit resources to supply goods or services.

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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as Junior Subordinated Notes, which have a lower priority than senior instruments.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes loans held for sale. Excludes loans and leases covered under loss sharing agreements.

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Fair Value Measurements - Estimated Fair Values of Company's Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
FINANCIAL ASSETS
Cash and cash equivalents	$ 1,857,535	$ 1,945,148	$ 1,707,733	$ 1,204,079
Securities held for investment	11,986	16,416
Loans, net	3,348,112	3,203,702
FINANCIAL LIABILITIES
Deposits	5,419,519	5,440,830
Short-term borrowings	4,590	4,571
Long-term borrowings	6,938	9,178
Junior subordinated debentures	26,804	26,804
Carrying Amount [Member]
OFF-BALANCE SHEET FINANCIAL INSTRUMENTS
Loan commitments
Letters of credit
Carrying Amount [Member] \| Level 2 Inputs [Member]
FINANCIAL ASSETS
Cash and cash equivalents	1,857,535	1,945,848
Securities held for investment	11,986	16,416
FINANCIAL LIABILITIES
Deposits	5,419,519	5,440,830
Short-term borrowings	4,590	4,571
Long-term borrowings	6,938	9,178
Junior subordinated debentures	26,804	26,804
Carrying Amount [Member] \| Level 3 Inputs [Member]
FINANCIAL ASSETS
Loans, net	3,348,112	3,203,702
Fair Value [Member]
OFF-BALANCE SHEET FINANCIAL INSTRUMENTS
Loan commitments	1,654	1,498
Letters of credit	459	440
Fair Value [Member] \| Level 2 Inputs [Member]
FINANCIAL ASSETS
Cash and cash equivalents	1,857,535	1,945,848
Securities held for investment	12,094	16,689
FINANCIAL LIABILITIES
Deposits	5,451,114	5,466,958
Short-term borrowings	4,590	4,571
Long-term borrowings	6,908	9,224
Junior subordinated debentures	29,259	28,144
Fair Value [Member] \| Level 3 Inputs [Member]
FINANCIAL ASSETS
Loans, net	$ 3,364,940	$ 3,264,948