BUSINESS COMBINATIONS BUSINESS COMBINATIONS (Textual) (Details) (USD $)	12 Months Ended	3 Months Ended	0 Months Ended
	Dec. 31, 2014	Mar. 31, 2015	Mar. 06, 2015	Dec. 31, 2013	Jun. 20, 2014
Business Acquisition [Line Items]
Goodwill	$ 0	21,148,000	$ 21,148,000	$ 0
Bargain purchase gain on acquisition	(9,079,000)
Six Oregon Branches [Member]
Business Acquisition [Line Items]
Acquisition Date	Jun. 20, 2014
Number of branches acquired	6
Total assets acquired					221,206,000
Deposits					212,085,000
Loans receivable					87,923,000
Core deposit intangible					2,372,000
Acquired finite-lived intangible assets, weighted average useful life		8 years
Bargain purchase discount					7,000,000
Net fair value adjustments on acquired assets and liabilities					(300,000)
Siuslaw Financial Group, Inc [Member]
Business Acquisition [Line Items]
Acquisition Date			Mar. 06, 2015
Equity interest issued to Siuslaw's shareholders per share			0.32231
Cash payment issued to Siuslaw's shareholders (usd per share)			$ 1.41622
Percentage of voting interests acquired			100.00%
Total assets acquired			370,306,000
Deposits			316,406,000
Loans receivable			247,098,000
Core deposit intangible			3,895,000
Acquired finite-lived intangible assets, weighted average useful life		8 years
Acquired receivables, non-credit-impaired			244,200,000
Acquired receivables, non-credit-impaired, fair value			241,400,000
Acquired receivables, discount			$ (2,800,000)