The amount of identifiable net tangible assets acquired at the acquisition date.

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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Amount of assets acquired at the acquisition date.

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Amount of deferred tax liability attributable to taxable temporary differences assumed at the acquisition date.

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The amount of identifiable intangible assets recognized as of the acquisition date.

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Amount of other liabilities due after one year or the normal operating cycle, if longer, assumed at the acquisition date.

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Remaining amortization period of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense.

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The cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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ACQUISITIONS (Details) shares in Thousands, $ in Thousands									3 Months Ended			6 Months Ended
ACQUISITIONS (Details) shares in Thousands, $ in Thousands	Apr. 02, 2018 USD ($)	Jan. 02, 2018 USD ($)	Dec. 04, 2017 USD ($) shares	Nov. 17, 2017 USD ($)	May 12, 2017 USD ($) Branch Location shares	Mar. 01, 2017 USD ($)	Feb. 03, 2017 USD ($)	Jan. 01, 2017 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	Jan. 02, 2017 USD ($)
Acquisitions [Abstract]
Cash												$ 1,737	$ 105,402
Goodwill									$ 733,479		$ 733,604	733,479	733,604	$ 734,430
HR Consultants (SA), LLC [Member]
Acquisitions [Abstract]
Cash	$ 300
HR Consultants (SA), LLC [Member] \| Customer Lists [Member]
Acquisitions [Abstract]
Intangibles	$ 300
Penna & Associates Agency, Inc. [Member]
Acquisitions [Abstract]
Cash		$ 800
Goodwill		300
Penna & Associates Agency, Inc. [Member] \| Customer Lists [Member]
Acquisitions [Abstract]
Intangibles		300
Styles Bridges Associates [Member]
Acquisitions [Abstract]
Cash		700
Styles Bridges Associates [Member] \| Customer Lists [Member]
Acquisitions [Abstract]
Intangibles		$ 700
Gordon B. Roberts Agency, Inc [Member]
Acquisitions [Abstract]
Purchase price of acquisition			$ 3,700
Cash			$ 1,350
Issuance of common shares (in shares) \| shares			40
Other liabilities			$ 600
Goodwill			2,100
Assets acquired			600
Increase (decrease) in other liabilities as a result of reclassification and adjustment									(90)
Increase (decrease) in goodwill as a result of fair value adjustment									(90)
Gordon B. Roberts Agency, Inc [Member] \| Other Intangibles [Member]
Acquisitions [Abstract]
Intangibles			$ 1,600
Northeast Capital Management, Inc [Member]
Acquisitions [Abstract]
Cash				$ 1,200
Northeast Capital Management, Inc [Member] \| Customer Lists [Member]
Acquisitions [Abstract]
Intangibles				$ 1,200
Merchants Bancshares, Inc. [Member]
Acquisitions [Abstract]
Purchase price of acquisition					$ 345,152
Cash					$ 82,898
Issuance of common shares (in shares) \| shares					4,680
Other liabilities					$ 11,750
Goodwill					189,046
Assets acquired					$ 2,000,000
Revenues earned									16,100		8,900	32,200	8,900
Expenses incurred									7,600		4,000	15,400	4,000
Merchants Bancshares, Inc. [Member] \| VERMONT [Member]
Acquisitions [Abstract]
Number of branch locations added upon merger \| Branch					31
Merchants Bancshares, Inc. [Member] \| Massachusetts [Member]
Acquisitions [Abstract]
Number of branch locations added upon merger \| Location					1
Merchants Bancshares, Inc. [Member] \| Other Intangibles [Member]
Acquisitions [Abstract]
Intangibles					$ 2,857
Dryfoos [Member]
Acquisitions [Abstract]
Cash						$ 3,000
Goodwill						1,700
Dryfoos [Member] \| Other Intangibles [Member]
Acquisitions [Abstract]
Intangibles						$ 1,700
BAS [Member]
Acquisitions [Abstract]
Cash								$ 1,200
BAS [Member] \| Other Intangibles [Member]
Acquisitions [Abstract]
Intangibles															$ 1,200
Northeast Retirement Services, Inc. [Member]
Acquisitions [Abstract]
Purchase price of acquisition							$ 148,556
Cash							70,073
Other liabilities							26,828
Goodwill							75,256
Tangible assets, net							$ 36,100
Factor of straight-line rate of depreciation used in declining balance depreciation method							150.00%
Period of amortization							10 years
Deferred tax liability							$ 23,000
Revenues earned									9,700		8,400	19,800	13,400
Expenses incurred									$ 6,000		$ 5,700	$ 12,000	$ 9,300
Increase (decrease) in other liabilities as a result of reclassification and adjustment										$ (1,200)
Increase (decrease) in goodwill as a result of fair value adjustment										$ (1,200)
Northeast Retirement Services, Inc. [Member] \| Other Intangibles [Member]
Acquisitions [Abstract]
Intangibles							$ 60,200