RECENT DEVELOPMENTS AND SIGNIFICANT EVENTS RECENT DEVELOPMENTS AND SIGNIFICANT EVENTS (Details) shares in Thousands, $ in Thousands	Oct. 01, 2015 USD ($) bank_branch shares	Mar. 06, 2015 USD ($) bank_branch
Siuslaw Financial Group, Inc [Member]
Business Acquisition [Line Items]
Number of branches acquired | bank_branch		10
Cash paid		$ 5,806
Total assets acquired		$ 370,306
Subsequent Event [Member] | Starbuck Bancshares, Inc [Member]
Business Acquisition [Line Items]
Number of branches acquired | bank_branch	203
Cash paid	$ 130,000
Common Stock Issued, Shares | shares	13,230
Total assets acquired	$ 9,900,000
Washington, Oregon, Idaho, California and Utah | Subsequent Event [Member] | Starbuck Bancshares, Inc [Member]
Business Acquisition [Line Items]
Number of branches acquired | bank_branch	98
Lane County, Oregon [Member] | Siuslaw Financial Group, Inc [Member]
Business Acquisition [Line Items]
Number of branches acquired | bank_branch		10