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Borrowings - Summary of Information Pertaining to Borrowings (Details) - USD ($) $ in Thousands | Jun. 30, 2018 | Dec. 31, 2017
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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 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 -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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