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ACCOUNTING POLICIES (Details) $ / shares in Units, $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2017 USD ($) Component Calculation Segment Factor $ / shares | Mar. 31, 2016 USD ($) $ / shares
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Number of broad components used in allowance methodology | Component | 2 |
Number of calculations used for general loan loss allocation | Calculation | 2 |
Number of main loan segments | Segment | 5 |
Period of historical net charge-off data for each loan class used in determining allowance level | 36 months |
Number of qualitative environmental factors used in qualitative calculation for loan loss allocation | Factor | 8 |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |
Net income | $ 26,257 | $ 24,403
Net income per diluted common share (in dollars per share) | $ / shares | $ 0.57 | $ 0.55
Core Deposits [Member] | Minimum [Member] |  |
Finite-Lived Intangible Assets [Line Items] |  |
Intangible asset useful life (amortization period) | 7 years |
Core Deposits [Member] | Maximum [Member] |  |
Finite-Lived Intangible Assets [Line Items] |  |
Intangible asset useful life (amortization period) | 20 years |
Customer Relationships [Member] | Minimum [Member] |  |
Finite-Lived Intangible Assets [Line Items] |  |
Intangible asset useful life (amortization period) | 7 years |
Customer Relationships [Member] | Maximum [Member] |  |
Finite-Lived Intangible Assets [Line Items] |  |
Intangible asset useful life (amortization period) | 20 years |
Commercial Portfolio Segment [Member] | Minimum [Member] |  |
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Threshold balance of loans individually evaluated for impairment | $ 500 |
ASU 2016-09 [Member] |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |
Net income | $ 2,200 |
Net income per diluted common share (in dollars per share) | $ / shares | $ 0.05 |

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