BANNER CORPORATION (PARENT COMPANY ONLY) (Statements of Financial Position) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2009
ASSETS
Other assets	$ 26,799	$ 40,781
Total assets	4,388,166	4,265,564
LIABILITIES AND STOCKHOLDERS’ EQUITY
Junior subordinated debentures at fair value	73,928	73,063
Stockholders’ equity	538,972	506,919	532,450	511,472
Total liabilities and stockholders' equity	4,388,166	4,265,564
Banner Corporation
ASSETS
Cash	45,998	36,884
Investment in trust equities	3,716	3,716
Investment in subsidiaries	575,023	556,125
Other assets	7,280	2,601
Total assets	632,017	599,326
LIABILITIES AND STOCKHOLDERS’ EQUITY
Miscellaneous liabilities	6,157	6,401
Deferred tax liability	12,960	12,943
Junior subordinated debentures at fair value	73,928	73,063
Stockholders’ equity	538,972	506,919
Total liabilities and stockholders' equity	$ 632,017	$ 599,326