Short-Term Borrowings and Long-Term Debt - Outstanding Short Term Borrowings and Long Term Debt (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2016	Dec. 31, 2015
Debt Outstanding [Line Items]
Federal Home Loan Bank Advances	$ 0	$ 638,000
Other Short-term Borrowings	0	1,900
Short-term borrowings	0	774,900
Total long-term debt	796,570	796,702
Federal funds purchased
Debt Outstanding [Line Items]
Short-term borrowings	$ 0	135,000
3.50% Senior Notes
Debt Outstanding [Line Items]
Maturity	Jan. 29, 2025
Principal value at period end	$ 350,000
Senior Notes	$ 346,744	346,667
5.375% Senior Notes
Debt Outstanding [Line Items]
Maturity	Sep. 15, 2020
Principal value at period end	$ 350,000
Senior Notes	$ 347,155	347,016
6.05% Subordinated Notes
Debt Outstanding [Line Items]
Maturity	Jun. 01, 2017
Principal value at period end	$ 45,964
Subordinated Notes	$ 48,045	48,350
7.0% Junior Subordinated Debentures
Debt Outstanding [Line Items]
Maturity	Oct. 15, 2033
Principal value at period end	$ 50,000
Junior Subordinated Debentures	$ 54,626	$ 54,669

Debt Outstanding [Line Items]

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- Definition

The amount shown on the books that a bank with insufficient reserves borrows, at the federal funds rate, from another bank to meet its reserve requirements and the amount of securities that an institution sells and agrees to repurchase at a specified date for a specified price, net of any reductions or offsets. Also reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

+ References

No definition available.

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- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
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- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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- Definition

Amount of Federal Home Loan Bank (FHLBank) advances to member financial institutions.

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No definition available.

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- Definition

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.

+ References

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- Definition

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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- Definition

Sum of the carrying amounts at the balance sheet date of short-term borrowings not otherwise specified in the taxonomy having initial terms less than one year or the normal operating cycle, if longer.

+ References

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- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

+ References

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- Definition

Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of subordinated debt (with initial maturities beyond one year or beyond the operating cycle if longer). Subordinated debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets.

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