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Borrowings - Summary of Information Pertaining to Borrowings (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Long Term And Short Term Debt [Line Items]
Short-term borrowings, Balance	$ 644,724	$ 590,161
Long-term borrowings, Balance	91,681	92,920
Total Borrowings, Balance	$ 736,405	$ 683,081
Short-term borrowings, Weighted Average Rate	2.04%	1.38%
Long-term borrowings, Weighted Average Rate	3.55%	2.81%
Total Borrowings, Weighted Average Rate	2.23%	1.57%
Securities sold under repurchase agreements
Long Term And Short Term Debt [Line Items]
Short-term borrowings, Balance	$ 44,724	$ 50,161
Short-term borrowings, Weighted Average Rate	0.46%	0.39%
Short-term borrowings
Long Term And Short Term Debt [Line Items]
Short-term borrowings, Balance	$ 600,000	$ 540,000
Short-term borrowings, Weighted Average Rate	2.16%	1.47%
Long-term borrowings
Long Term And Short Term Debt [Line Items]
Long-term borrowings, Balance	$ 46,062	$ 47,301
Long-term borrowings, Weighted Average Rate	2.31%	1.88%
Junior subordinated debt securities
Long Term And Short Term Debt [Line Items]
Long-term borrowings, Balance	$ 45,619	$ 45,619
Long-term borrowings, Weighted Average Rate	4.80%	3.78%

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- Definition

Long Term And Short Term Debt [Line Items]

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Represents the aggregate of total long-term debt, including current maturities and short-term debt.

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Weighted average interest rate of debt outstanding.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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-Topic 470
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Weighted average interest rate of long-term debt outstanding calculated at point in time.

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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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Weighted average interest rate of short-term debt outstanding calculated at point in time.

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