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LOANS, Amount of Business Lending Loans by Credit Quality Category (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 6,227,030	$ 6,256,757
Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	4,691,880	4,619,663
Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,535,150	1,637,094
Business Lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	2,426,086	2,424,223
Business Lending [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,450,006	1,376,599
Business Lending [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	976,080	1,047,624
Business Lending [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	2,145,327	2,134,137
Business Lending [Member] | Pass [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,253,688	1,170,156
Business Lending [Member] | Pass [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	891,639	963,981
Business Lending [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	163,915	166,397
Business Lending [Member] | Special Mention [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	120,881	129,076
Business Lending [Member] | Special Mention [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	43,034	37,321
Business Lending [Member] | Classified [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	106,596	111,995
Business Lending [Member] | Classified [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	75,283	77,367
Business Lending [Member] | Classified [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	31,313	34,628
Business Lending [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,752	1,579
Business Lending [Member] | Doubtful [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	154	0
Business Lending [Member] | Doubtful [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,598	1,579
Business Lending [Member] | Acquired Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	8,496	10,115
Business Lending [Member] | Acquired Impaired [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Business Lending [Member] | Acquired Impaired [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	8,496	10,115
All Other Loans [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	3,241,874	3,243,064
All Other Loans [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	559,070	589,470
All Other Loans [Member] | Performing [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	3,228,719	3,229,051
All Other Loans [Member] | Performing [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	554,428	584,874
All Other Loans [Member] | Nonperforming [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	13,155	14,013
All Other Loans [Member] | Nonperforming [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	4,642	4,596
Consumer Mortgage [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,765,864	1,754,609
Consumer Mortgage [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	446,018	465,689
Consumer Mortgage [Member] | Performing [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,754,341	1,742,387
Consumer Mortgage [Member] | Performing [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	442,881	462,597
Consumer Mortgage [Member] | Nonperforming [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	11,523	12,222
Consumer Mortgage [Member] | Nonperforming [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	3,137	3,092
Consumer Indirect [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	990,766	991,836
Consumer Indirect [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	17,432	20,142
Consumer Indirect [Member] | Performing [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	990,579	991,541
Consumer Indirect [Member] | Performing [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	17,397	20,134
Consumer Indirect [Member] | Nonperforming [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	187	295
Consumer Indirect [Member] | Nonperforming [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	35	8
Consumer Direct [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	168,517	174,479
Consumer Direct [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	4,515	5,450
Consumer Direct [Member] | Performing [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	168,487	174,431
Consumer Direct [Member] | Performing [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	4,515	5,450
Consumer Direct [Member] | Nonperforming [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	30	48
Consumer Direct [Member] | Nonperforming [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Home Equity [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	316,727	322,140
Home Equity [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	91,105	98,189
Home Equity [Member] | Performing [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	315,312	320,692
Home Equity [Member] | Performing [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	89,635	96,693
Home Equity [Member] | Nonperforming [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,415	1,448
Home Equity [Member] | Nonperforming [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 1,470	$ 1,496

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+ References

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522

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