LOANS, Amount of Business Lending Loans by Credit Quality Category (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 4,948,562	$ 4,801,375
Legacy Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	4,453,202	4,183,721
Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	495,360	617,654
Business Lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,490,076	1,497,271
Business Lending [Member] | Legacy Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,277,666	1,233,628
Business Lending [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	212,410	263,643
Business Lending [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,213,170	1,267,738
Business Lending [Member] | Pass [Member] | Legacy Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,051,005	1,048,364
Business Lending [Member] | Pass [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	162,165	219,374
Business Lending [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	165,292	144,775
Business Lending [Member] | Special Mention [Member] | Legacy Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	135,602	124,768
Business Lending [Member] | Special Mention [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	29,690	20,007
Business Lending [Member] | Classified [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	105,587	77,144
Business Lending [Member] | Classified [Member] | Legacy Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	90,585	60,181
Business Lending [Member] | Classified [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	15,002	16,963
Business Lending [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	474	315
Business Lending [Member] | Doubtful [Member] | Legacy Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	474	315
Business Lending [Member] | Doubtful [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Business Lending [Member] | Acquired Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	5,553	7,299
Business Lending [Member] | Acquired Impaired [Member] | Legacy Loan [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	5,553	7,299
All Other Loans [Member] | Legacy Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	3,175,536	2,950,093
All Other Loans [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	282,950	354,011
All Other Loans [Member] | Performing [Member] | Legacy Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	3,160,929	2,934,994
All Other Loans [Member] | Performing [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	279,070	351,880
All Other Loans [Member] | Nonperforming [Member] | Legacy Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	14,607	15,099
All Other Loans [Member] | Nonperforming [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	3,880	2,131
Consumer Mortgage [Member] | Legacy Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,659,760	1,581,458
Consumer Mortgage [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	159,941	188,296
Consumer Mortgage [Member] | Performing [Member] | Legacy Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,647,228	1,568,653
Consumer Mortgage [Member] | Performing [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	157,404	186,506
Consumer Mortgage [Member] | Nonperforming [Member] | Legacy Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	12,532	12,805
Consumer Mortgage [Member] | Nonperforming [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	2,537	1,790
Consumer Indirect [Member] | Legacy Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,014,825	890,339
Consumer Indirect [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	30,147	45,421
Consumer Indirect [Member] | Performing [Member] | Legacy Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,014,659	890,237
Consumer Indirect [Member] | Performing [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	30,144	45,421
Consumer Indirect [Member] | Nonperforming [Member] | Legacy Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	166	102
Consumer Indirect [Member] | Nonperforming [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	3	0
Consumer Direct [Member] | Legacy Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	181,922	178,051
Consumer Direct [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	9,893	17,025
Consumer Direct [Member] | Performing [Member] | Legacy Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	181,864	177,999
Consumer Direct [Member] | Performing [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	9,893	17,011
Consumer Direct [Member] | Nonperforming [Member] | Legacy Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	58	52
Consumer Direct [Member] | Nonperforming [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	0	14
Home Equity [Member] | Legacy Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	319,029	300,245
Home Equity [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	82,969	103,269
Home Equity [Member] | Performing [Member] | Legacy Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	317,178	298,105
Home Equity [Member] | Performing [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	81,629	102,942
Home Equity [Member] | Nonperforming [Member] | Legacy Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,851	2,140
Home Equity [Member] | Nonperforming [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 1,340	$ 327