OTHER BORROWINGS (Schedule of Other Borrowings) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Long-Term and Short-Term Debt Instruments [Line Items]
Total year-end outstanding	$ 76,633		$ 152,128
Repurchase Agreements [Member] | Retail repurchase agreements [Member]
Long-Term and Short-Term Debt Instruments [Line Items]
Due in one year or less	76,633		102,131
Due in one year or less, weighted average interest rate	0.30%		0.29%
Total year-end outstanding	76,633		102,131
Total year-end outstanding, weighted average interest rate	0.30%		0.29%
Average outstanding	90,017		103,704
Average outstanding, weighted average interest rate	0.31%		0.34%
Maximum outstanding at any month end	100,949		125,136
Subsidiary, Banner Bank [Member] | Senior Notes [Member] | Temporary liquidity guarantee program notes [Member]
Long-Term and Short-Term Debt Instruments [Line Items]
Due in one year or less	0	[1]	49,997	[1]
Due in one year or less, weighted average interest rate	0.00%	[1]	3.82%	[1]
Total year-end outstanding	0	[1]	49,997	[1]
Total year-end outstanding, weighted average interest rate	0.00%	[1]	3.82%	[1]
Average outstanding	12,158	[1]	49,993	[1]
Average outstanding, weighted average interest rate	3.92%	[1]	3.82%	[1]
Maximum outstanding and any month end	$ 49,999	[1]	$ 49,997	[1]

[1] These notes matured and were repaid on March 31, 2012. Weighted average rate includes FDIC guarantee fee and amortization of origination costs.