| **INVESTMENT SECURITIES (Concentration Risk) (Details) - Geographic concentration risk - Total available-for-sale securities** | 12 Months Ended |
|--------------------------------------------------------------------------------------------------------------------------------|-----------------|
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| Connecticut                                                                                                                    |            |
| **Concentration Risk [Line Items]**                                                                                            |            |
| Concentration risk, percentage                                                                                                 | 12.10%          |
| Massachusetts                                                                                                                  |            |
| **Concentration Risk [Line Items]**                                                                                            |            |
| Concentration risk, percentage                                                                                                 | 14.70%          |
| Washington                                                                                                                     |            |
| **Concentration Risk [Line Items]**                                                                                            |            |
| Concentration risk, percentage                                                                                                 | 21.50%          |
| Other states | Maximum                                                                                                         |            |
| **Concentration Risk [Line Items]**                                                                                            |            |
| Concentration risk, percentage                                                                                                 | 10.00%          |

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| - Definition
Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
+ References
No definition available.
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| - Definition
For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=51801978&loc=d3e6351-108592Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13531-108611Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=51801978&loc=d3e6404-108592Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13537-108611
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