LOANS - Loans Evaluated for Impairment (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Allowance for loan losses
Total loans	$ 6,549,787	$ 5,725,236
Business Activities Loans
Allowance for loan losses
Individually evaluated for impairment	36,732	23,373
Collectively evaluated	5,184,575	4,537,310
Total loans	5,221,307	4,560,683
Acquired Loans
Allowance for loan losses
Individually evaluated for impairment	5,605	4,806
Purchased credit-impaired loans	46,816	21,362
Collectively evaluated	1,276,059	1,138,385
Total loans	1,328,480	1,164,553
Commercial real estate
Allowance for loan losses
Total loans	2,616,438	2,059,767
Commercial real estate \| Business Activities Loans
Allowance for loan losses
Individually evaluated for impairment	25,549	11,560
Collectively evaluated	1,900,795	1,622,467
Total loans	1,926,344	1,634,027
Commercial real estate \| Acquired Loans
Allowance for loan losses
Individually evaluated for impairment	4,256	3,749
Purchased credit-impaired loans	34,820	15,765
Collectively evaluated	651,018	406,226
Total loans	690,094	425,740
Commercial and industrial
Allowance for loan losses
Total loans	1,062,038	1,048,263
Commercial and industrial \| Business Activities Loans
Allowance for loan losses
Individually evaluated for impairment	5,705	7,191
Collectively evaluated	902,397	820,041
Total loans	908,102	827,232
Commercial and industrial \| Acquired Loans
Allowance for loan losses
Individually evaluated for impairment	635	0
Purchased credit-impaired loans	3,369	2,775
Collectively evaluated	149,932	218,256
Total loans	153,936	221,031
Residential mortgages
Allowance for loan losses
Total loans	1,893,131	1,815,035
Residential mortgages \| Business Activities Loans
Allowance for loan losses
Individually evaluated for impairment	2,775	2,812
Collectively evaluated	1,592,197	1,478,125
Total loans	1,594,972	1,480,937
Residential mortgages \| Acquired Loans
Allowance for loan losses
Individually evaluated for impairment	308	570
Purchased credit-impaired loans	7,283	2,572
Collectively evaluated	290,568	330,956
Total loans	298,159	334,098
Consumer
Allowance for loan losses
Total loans	978,180	802,171
Consumer \| Business Activities Loans
Allowance for loan losses
Individually evaluated for impairment	2,703	1,810
Collectively evaluated	789,186	616,677
Total loans	791,889	618,487
Consumer \| Acquired Loans
Allowance for loan losses
Individually evaluated for impairment	406	487
Purchased credit-impaired loans	1,344	250
Collectively evaluated	184,541	182,947
Total loans	$ 186,291	$ 183,684

Financing Receivable, Purchased Credit-Impaired Loans

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+ References

No definition available.

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- Definition

The balance of financing receivables that were collectively evaluated for impairment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524

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The balance of financing receivables that were individually evaluated for impairment.

+ References

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- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. 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=65884687&loc=d3e4428-111522

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5074-111524

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