STOCK-BASED COMPENSATION PLANS (Textuals) (Details) (USD $)	12 Months Ended						0 Months Ended	20 Months Ended	0 Months Ended	40 Months Ended	12 Months Ended						0 Months Ended	12 Months Ended	20 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Restricted Stock [Member]	Dec. 31, 2012 Restricted Stock [Member]	Dec. 31, 2011 Restricted Stock [Member]	Apr. 24, 2012 2012 Restricted Stock Plan [Member] Restricted Stock [Member]	Dec. 31, 2013 2012 Restricted Stock Plan [Member] Restricted Stock [Member]	Aug. 23, 2010 CEO Employment Agreement Restricted Stock Plan [Member] Restricted Stock [Member]	Dec. 31, 2013 CEO Employment Agreement Restricted Stock Plan [Member] Restricted Stock [Member]	Dec. 31, 2013 SOPs [Member] Stock Options [Member]	Dec. 31, 2012 SOPs [Member] Stock Options [Member]	Dec. 31, 2011 SOPs [Member] Stock Options [Member]	Dec. 31, 2013 Banner Corporation Long-Term Incentive Plan [Member] Stock Appreciation Rights (SARs) [Member]	Dec. 31, 2012 Banner Corporation Long-Term Incentive Plan [Member] Stock Appreciation Rights (SARs) [Member]	Dec. 31, 2011 Banner Corporation Long-Term Incentive Plan [Member] Stock Appreciation Rights (SARs) [Member]	Apr. 24, 2012 Chief Executive Officer [Member] 2012 Restricted Stock Plan [Member] Restricted Stock [Member]	Dec. 31, 2013 Chief Executive Officer [Member] 2012 Restricted Stock Plan [Member] Restricted Stock [Member] increment	Dec. 31, 2013 Officer [Member] 2012 Restricted Stock Plan [Member] Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period											0	0	0
Number of increments shares vest annually																		3
Award vesting period							3 years		3 years
Maximum contractual term							10 years
Number of shares authorized							300,000				2,284,186
Shares outstanding on expiration date				98,891	92,035	17,692		189,426		34,257							14,535		174,891
Stock-based compensation expense	$ 0	$ 11,000	$ 39,000	$ 1,500,000	$ 434,000	$ 111,000					$ 0	$ 7,000	$ 25,000	$ 1,000,000	$ 314,000	$ 148,000
Unrecognized compensation expense				3,300,000
Unrecognized compensation expense, period for recognition				28 months
Exercise price percentage of fair value of stock											100.00%
Annual vesting percentage											20.00%
Award termination period											10 years
Award forfeiture period											90 days
Options granted											0	0	0
Deferred compensation liability	$ 16,442,000	$ 14,452,000												$ 1,600,000