BUSINESS COMBINATIONS BUSINESS COMBINATIONS (Textual) (Details) $ / shares in Units, $ in Thousands			3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 06, 2015 USD ($) $ / shares	Jun. 20, 2014 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) bank_branch	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($) location	Dec. 31, 2013 USD ($)
Business Acquisition [Line Items]
Goodwill			$ 21,148		$ 21,148		$ 0	$ 0
Bargain purchase gain on acquisition			$ 0	$ (9,079)	$ 0	$ (9,079)
Six Oregon Branches [Member]
Business Acquisition [Line Items]
Acquisition Date							Jun. 20, 2014
Number of branches acquired | location							6
Total assets acquired		$ 221,206
Deposits acquired		212,085
Loans receivable acquired		87,923
Core deposit intangible		2,372
Acquired finite-lived intangible assets, weighted average useful life					8 years
Bargain purchase gain on acquisition		(9,079)
Bargain purchase discount		7,000
Net fair value adjustments on acquired assets and liabilities		$ (300)
Siuslaw Financial Group, Inc [Member]
Business Acquisition [Line Items]
Acquisition Date	Mar. 06, 2015
Number of branches acquired | bank_branch					10
Equity interest issued to Siuslaw's shareholders per share | $ / shares	$ 0.32231
Cash payment issued to Siuslaw's shareholders (usd per share) | $ / shares	$ 1.41622
Total assets acquired	$ 370,306
Deposits acquired	316,406
Loans receivable acquired	247,098
Core deposit intangible	3,895
Goodwill	21,148
Acquired finite-lived intangible assets, weighted average useful life					8 years
Acquired receivables, non-credit-impaired	244,200
Acquired receivables, non-credit-impaired, fair value	241,400
Acquired receivables, discount	$ (2,800)