LOANS - Loans Evaluated for Impairment (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Loans receivable: balance at end of period
Total loans	$ 9,941,828	$ 9,043,253
Commercial real estate
Loans receivable: balance at end of period
Total loans	4,005,347	3,400,221
Commercial and industrial loans
Loans receivable: balance at end of period
Total loans	1,987,297	1,980,046
Residential mortgages
Loans receivable: balance at end of period
Total loans	2,882,380	2,566,424
Consumer
Loans receivable: balance at end of period
Total loans	1,066,804	1,096,562
Business Activities Loans
Loans receivable: balance at end of period
Individually evaluated for impairment	31,767	28,601
Collectively evaluated for impairment	7,262,638	7,338,143
Total loans	7,294,405	7,366,744
Business Activities Loans \| Commercial real estate
Loans receivable: balance at end of period
Individually evaluated for impairment	22,035	23,345
Collectively evaluated for impairment	2,637,463	2,565,366
Total loans	2,659,498	2,588,711
Business Activities Loans \| Commercial and industrial loans
Loans receivable: balance at end of period
Individually evaluated for impairment	6,753	2,825
Collectively evaluated for impairment	1,465,013	1,510,713
Total loans	1,471,766	1,513,538
Business Activities Loans \| Residential mortgages
Loans receivable: balance at end of period
Individually evaluated for impairment	2,841	2,089
Collectively evaluated for impairment	2,274,774	2,325,209
Total loans	2,277,615	2,327,298
Business Activities Loans \| Consumer
Loans receivable: balance at end of period
Individually evaluated for impairment	138	342
Collectively evaluated for impairment	885,388	936,855
Total loans	885,526	937,197
Acquired Loans
Loans receivable: balance at end of period
Individually evaluated for impairment	5,170	5,751
Purchased credit-impaired loans	74,092	47,288
Collectively evaluated for impairment	2,568,161	1,623,470
Total loans	2,647,423	1,676,509
Acquired Loans \| Commercial real estate
Loans receivable: balance at end of period
Individually evaluated for impairment	3,709	3,980
Purchased credit-impaired loans	29,623	11,994
Collectively evaluated for impairment	1,312,517	795,536
Total loans	1,345,849	811,510
Acquired Loans \| Commercial and industrial loans
Loans receivable: balance at end of period
Individually evaluated for impairment	372	763
Purchased credit-impaired loans	31,456	29,539
Collectively evaluated for impairment	483,703	436,206
Total loans	515,531	466,508
Acquired Loans \| Residential mortgages
Loans receivable: balance at end of period
Individually evaluated for impairment	740	362
Purchased credit-impaired loans	12,050	4,888
Collectively evaluated for impairment	591,975	233,876
Total loans	604,765	239,126
Acquired Loans \| Consumer
Loans receivable: balance at end of period
Individually evaluated for impairment	349	646
Purchased credit-impaired loans	963	867
Collectively evaluated for impairment	179,966	157,852
Total loans	$ 181,278	$ 159,365

Financing Receivable, Purchased Credit-Impaired Loans

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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524

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- Definition

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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=118952595&loc=d3e4428-111522

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5074-111524

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- References

No definition available.

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