ADVANCES FROM FEDERAL HOME LOAN BANK OF SEATTLE (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Amount:
Due in one year or less	$ 10,000,000	$ 0
Due after one year through three years	0	10,000,000
Due after three years through five years	0	0
Due after five years	210,000	217,000
Total FHLB advances, at par	10,210,000	10,217,000	43,023,000
Fair value adjustment	94,000	316,000
Total FHLB advances, carried at fair value	10,304,000	10,533,000
Weighted Average Rate:
Due in one year or less, weighted average rate	2.38%	0.00%
Due after one year through three years, weighted average rate	0.00%	2.38%
Due after three years through five years, weighted average rate	0.00%	0.00%
Due after five years, weighted average rate	5.94%	5.94%
Total FHLB advances, at par, weighted average rate	2.45%	2.45%	2.67%
Federal Home Loan Bank, Advances, Activity for Year [Abstract]
Maximum outstanding at any month end, at par	10,216,000	36,522,000	66,028,000
Average outstanding, at par	10,215,000	14,699,000	51,411,000
Year-end outstanding at par	10,210,000	10,217,000	43,023,000
Weighted average interest rates, annual	2.49%	2.52%	2.56%
Weighted average interest rates, end of period	2.45%	2.45%	2.67%
Interest expense during the period	254,000	370,000	1,318,000
Subsidiary, Banner Bank [Member]
Federal Home Loan Bank, Advances, Activity for Year [Abstract]
Federal Home Loan Bank, advances, percentage of total assets to support credit line	35.00%
Federal Home Loan Bank, advances, maximum credit line	889,000,000
Subsidiary, Islanders Bank [Member]
Federal Home Loan Bank, Advances, Activity for Year [Abstract]
Federal Home Loan Bank, advances, percentage of total assets to support credit line	25.00%
Federal Home Loan Bank, advances, maximum credit line	$ 26,000,000