LOANS, Amount of Business Lending Loans by Credit Quality Category (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 4,940,621	$ 4,801,375
Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	4,407,086	4,183,721
Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	533,535	617,654
Business Lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,506,878	1,497,271
Business Lending [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,274,251	1,233,628
Business Lending [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	232,627	263,643
Business Lending [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,227,864	1,267,738
Business Lending [Member] | Pass [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,053,914	1,048,364
Business Lending [Member] | Pass [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	173,950	219,374
Business Lending [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	170,675	144,775
Business Lending [Member] | Special Mention [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	137,855	124,768
Business Lending [Member] | Special Mention [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	32,820	20,007
Business Lending [Member] | Classified [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	101,460	77,144
Business Lending [Member] | Classified [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	82,466	60,181
Business Lending [Member] | Classified [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	18,994	16,963
Business Lending [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	16	315
Business Lending [Member] | Doubtful [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	16	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	6,863	7,299
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	6,863	7,299
All Other Loans [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	3,132,835	2,950,093
All Other Loans [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	300,908	354,011
All Other Loans [Member] | Performing [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	3,118,164	2,934,994
All Other Loans [Member] | Performing [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	297,887	351,880
All Other Loans [Member] | Nonperforming [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	14,671	15,099
All Other Loans [Member] | Nonperforming [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	3,021	2,131
Consumer Mortgage [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,630,713	1,581,458
Consumer Mortgage [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	168,035	188,296
Consumer Mortgage [Member] | Performing [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,618,123	1,568,653
Consumer Mortgage [Member] | Performing [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	165,510	186,506
Consumer Mortgage [Member] | Nonperforming [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	12,590	12,805
Consumer Mortgage [Member] | Nonperforming [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	2,525	1,790
Consumer Indirect [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,003,842	890,339
Consumer Indirect [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	33,235	45,421
Consumer Indirect [Member] | Performing [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,003,680	890,237
Consumer Indirect [Member] | Performing [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	33,220	45,421
Consumer Indirect [Member] | Nonperforming [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	162	102
Consumer Indirect [Member] | Nonperforming [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	15	0
Consumer Direct [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	184,980	178,051
Consumer Direct [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	11,154	17,025
Consumer Direct [Member] | Performing [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	184,894	177,999
Consumer Direct [Member] | Performing [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	11,154	17,011
Consumer Direct [Member] | Nonperforming [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	86	52
Consumer Direct [Member] | Nonperforming [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	0	14
Home Equity [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	313,300	300,245
Home Equity [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	88,484	103,269
Home Equity [Member] | Performing [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	311,467	298,105
Home Equity [Member] | Performing [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	88,003	102,942
Home Equity [Member] | Nonperforming [Member] | Legacy Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,833	2,140
Home Equity [Member] | Nonperforming [Member] | Acquired Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 481	$ 327