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FAIR VALUE, Carrying Amounts and Estimated Fair Values of Other Financial Instruments (Details) - USD ($) $ in Thousands | Mar. 31, 2018 | Dec. 31, 2017
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Carrying Value [Member] |  |
Financial assets [Abstract] |  |
Net loans | $ 6,178,927 | $ 6,209,174
Financial liabilities [Abstract] |  |
Deposits | 8,771,092 | 8,444,420
Short-term borrowings | 0 | 24,000
Securities sold under agreement to repurchase, short-term | 279,702 | 337,011
Other long-term debt | 2,042 | 2,071
Subordinated debt held by unconsolidated subsidiary trusts | 122,820 | 122,814
Fair Value [Member] |  |
Financial assets [Abstract] |  |
Net loans | 6,154,483 | 6,244,941
Financial liabilities [Abstract] |  |
Deposits | 8,754,350 | 8,431,481
Short-term borrowings | 0 | 24,000
Securities sold under agreement to repurchase, short-term | 279,702 | 337,011
Other long-term debt | 1,971 | 2,021
Subordinated debt held by unconsolidated subsidiary trusts | $ 122,820 | $ 122,814

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- Definition Fair value portion of debt having initial terms less than one year or the normal operating cycle, if longer. + References No definition available. + Details
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- Definition Fair value of subordinated debt obligations including, but not limited to, subordinated loan, subordinated bond, subordinated debenture or junior debt. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
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- Definition Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -URI http://asc.fasb.org/subtopic&trid=2196772 + Details
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- Definition Fair value portion of securities that an entity sells and agrees to repurchase at a specified date for a specified price. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13433-108611 + Details
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