BUSINESS COMBINATIONS BUSINESS COMBINATIONS (Schedule of Acquisition-Related Costs) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Business Acquisition [Line Items]
Acquisition-related costs recognized in non-interest expenses:	$ 1,720	$ 2,207	$ 10,945	$ 7,741
Salary and Employee Benefits [Member]
Business Acquisition [Line Items]
Acquisition-related costs recognized in non-interest expenses:	16	227	1,304	443
Occupancy and Equipment [Member]
Business Acquisition [Line Items]
Acquisition-related costs recognized in non-interest expenses:	94	5	2,517	55
Advertising and Marketing [Member]
Business Acquisition [Line Items]
Acquisition-related costs recognized in non-interest expenses:	527	151	904	221
Information and Computer Data Services [Member]
Business Acquisition [Line Items]
Acquisition-related costs recognized in non-interest expenses:	459	301	2,409	807
Payment and Card Processing Expenses [Member]
Business Acquisition [Line Items]
Acquisition-related costs recognized in non-interest expenses:	0	16	0	16
Professional Services [Member]
Business Acquisition [Line Items]
Acquisition-related costs recognized in non-interest expenses:	687	1,185	2,138	5,411
Miscellaneous
Business Acquisition [Line Items]
Acquisition-related costs recognized in non-interest expenses:	(63)	322	1,673	788
Siuslaw Financial Group, Inc [Member]
Business Acquisition [Line Items]
Acquisition-related costs recognized in non-interest expenses:	1	340	95	1,867
Starbuck Bancshares, Inc [Member]
Business Acquisition [Line Items]
Acquisition-related costs recognized in non-interest expenses:	$ 1,719	$ 1,867	$ 10,850	$ 5,874