Borrowings - Summary of Long-Term Debt (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Debt Disclosure [Abstract]
Federal Home Loan Bank advances	$ 400,056	$ 50,076
Subordinated notes	83,133	84,637
Other subordinated debt		8,637
Convertible debt		578
Long-term debt	$ 483,189	$ 143,928

Including the current and noncurrent portions, carrying amount of debt identified as being convertible into another form of financial instrument (typically the entity's common stock) as of the balance sheet date, which originally required full repayment more than twelve months after issuance or greater than the normal operating cycle of the company.

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Including both current and noncurrent portions, Federal Home Loan Bank borrowings initially due beyond one year or beyond the normal operating cycle if longer.

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Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Including both current and noncurrent portions, carrying amount as of the balance sheet date of other forms of debt not elsewhere specified in the taxonomy with initial maturities beyond one year or beyond the normal operating cycle, if longer.

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Carrying value as of the balance sheet date of collateralized/uncollateralized debt obligation (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion. Subordinated debt places a lender in a lien position behind the primary lender of the company.

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