PENDING BUSINESS COMBINATION Pending Business Combination - Pro Forma Information (Details) - USD ($)	6 Months Ended	12 Months Ended
Jun. 30, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition, Pro Forma Information [Abstract]
Business Acquisition, Pro Forma Revenue	$ 204,518	$ 387,725
Business Acquisition, Pro Forma, Provision for Loan and Lease Losses	834	10,140
Business Acquisitions, Pro Forma Income Before Tax	92,591	170,132
Net Income	65,884	119,661
Business Acquisition, Pro Forma Balance Sheet Information [Abstract]
Loans and Leases Receivable, Net Amount	8,818,392	5,699,521,000	$ 5,959,162,000
Total assets	13,806,092	8,437,967,000	8,896,923,000
Deposits	9,987,298	6,525,788,000	6,895,046,000
Total shareholders' equity	$ 1,913,682	$ 865,224,000	$ 930,664,000	$ 809,376,000	$ 784,077,000

Business Acquisition, Pro Forma Balance Sheet Information [Abstract]

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Business Acquisition, Pro Forma, Provision for Loan and Lease Losses

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Business Acquisitions, Pro Forma Income Before Tax

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Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(12))
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The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
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-Paragraph 2
-Subparagraph (h)(2)-(3)
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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others.

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Amount after allowance and 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 and loans held for sale.

+ References

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-Publisher FASB
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-SubTopic 10
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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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