GOODWILL AND OTHER INTANGIBLE ASSETS (Gross Carrying Amouns and Accumulated Amortization of Intangible Assets and Goodwill) (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 12,155,000	$ 786,000
Accumulated Amortization	(1,828,000)	(206,000)
Net Carrying Amount	10,327,000	580,000
Goodwill	345,422,000	85,768,000
Finite-lived Intangible Assets Acquired	700,000
Other Identifiable Intangible Assets
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,477,000	786,000
Accumulated Amortization	(372,000)	(206,000)
Net Carrying Amount	$ 1,105,000	$ 580,000
Other Identifiable Intangible Assets | Weighted average [Member]
Finite Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	10 years 10 months	13 years
Core deposits [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 10,678,000	$ 0
Accumulated Amortization	(1,456,000)	0
Net Carrying Amount	$ 9,222,000	$ 0
Core deposits [Member] | Weighted average [Member]
Finite Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	9 years 4 months