BANNER CORPORATION (PARENT COMPANY ONLY) (Statements of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
OPERATING ACTIVITIES:
Net income	$ 46,555	$ 64,882	$ 5,457
Adjustments to reconcile net income to net cash provided by operating activities:
Increase (decrease) in deferred taxes	7,528	(35,007)	0
Net change in valuation of financial instruments carried at fair value	2,278	16,515	624
(Increase) decrease in other assets	19,421	(818)	17,960
Increase (decrease) in other liabilities	4,331	3,569	2,104
Net cash provided from operating activities	95,366	81,415	101,313
INVESTING ACTIVITIES:
Net cash provided from (used by) investing activities	(215,126)	52,479	(171,213)
FINANCING ACTIVITIES
Issuance of stock for stockholder reinvestment program	72	36,317	21,556
Redemption of preferred stock	0	(121,528)	0
Cash dividends paid	(7,799)	(6,470)	(8,827)
Net cash provided from (used by) financing activities	75,811	(85,032)	(159,316)
NET INCREASE (DECREASE) IN CASH AND DUE FROM BANKS	(43,949)	48,862	(229,216)
CASH AND DUE FROM BANKS, BEGINNING OF YEAR	181,298	132,436	361,652
CASH AND DUE FROM BANKS, END OF YEAR	137,349	181,298	132,436
Banner Corporation
OPERATING ACTIVITIES:
Net income	46,555	64,882	5,457
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed earnings of subsidiaries	(23,994)	(23,507)	(9,478)
Increase (decrease) in deferred taxes	17	(13,030)	(562)
Net change in valuation of financial instruments carried at fair value	865	23,075	1,563
(Increase) decrease in other assets	(4,655)	(496)	1,933
Increase (decrease) in other liabilities	(1,921)	4,940	(957)
Net cash provided from operating activities	16,867	55,864	(2,044)
INVESTING ACTIVITIES:
Funds transferred to deferred compensation trust	(27)	(332)	(162)
Net cash provided from (used by) investing activities	(27)	(332)	(162)
FINANCING ACTIVITIES
Issuance of stock for stockholder reinvestment program	72	36,317	21,556
Redemption of preferred stock	0	(121,528)	0
Cash dividends paid	(7,798)	(6,470)	(8,827)
Net cash provided from (used by) financing activities	(7,726)	(91,681)	12,729
NET INCREASE (DECREASE) IN CASH AND DUE FROM BANKS	9,114	(36,149)	10,523
CASH AND DUE FROM BANKS, BEGINNING OF YEAR	36,884	73,033	62,510
CASH AND DUE FROM BANKS, END OF YEAR	$ 45,998	$ 36,884	$ 73,033