Banner (BANR) 10-K 16 Mar 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Feb. 28, 2015	Jun. 30, 2014
Document and Entity Information [Abstract]
Entity Registrant Name	Banner Corporation
Document Type	10-K
Document Period End Date	31-Dec-14
Amendment Flag	FALSE
Entity Central Index Key	946673
Current Fiscal Year End Date	-19
Entity Common Stock, Shares Outstanding		19,579,326
Entity Public Float			$755,828,076
Entity Filer Category	Large Accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY

CONSOLIDATED_STATEMENTS_OF_FIN

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
ASSETS
Cash and due from banks	$126,072	$137,349
Securities—trading, amortized cost $47,480 and $75,150, respectively	40,258	62,472
Securities—available-for-sale, amortized cost $411,424 and $474,960, respectively	411,021	470,280
Securities—held-to-maturity, fair value $137,608 and $103,610, respectively	131,258	102,513
Federal Home Loan Bank stock	27,036	35,390
Loans receivable:
Held for sale	2,786	2,734
Held for portfolio	3,831,034	3,415,711
Allowance for loan losses	-75,907	-74,258
Total loans, net	3,757,913	3,344,187
Accrued interest receivable	15,279	13,996
Real estate owned (REO), held for sale, net	3,352	4,044
Property and equipment, net	91,185	90,267
Intangible assets, net	2,831	2,449
Bank-owned life insurance (BOLI)	63,759	61,945
Deferred tax assets, net	24,607	27,479
Income tax receivable, net	0	9,728
Other assets	29,328	26,799
Total assets	4,723,899	4,388,898
Deposits:
Non-interest-bearing	1,298,866	1,115,346
Interest-bearing transaction and savings accounts	1,829,568	1,629,885
Interest-bearing certificates	770,516	872,695
Total deposits	3,898,950	3,617,926
Advances from FHLB at fair value	32,250	27,250
Other borrowings	77,185	83,056
Junior subordinated debentures at fair value (issued in connection with Trust Preferred Securities)	78,001	73,928
Accrued expenses and other liabilities	37,082	31,324
Deferred compensation	16,807	16,442
Total liabilities	4,140,275	3,849,926
COMMITMENTS AND CONTINGENCIES (Notes 19 and 27)
STOCKHOLDERS’ EQUITY
Preferred stock - $0.01 par value, 500,000 shares authorized; no shares outstanding at December 31, 2014 and December 31, 2013	0	0
Common stock and paid in capital - $0.01 par value per share, 50,000,000 shares authorized, 19,571,548 shares issued and outstanding at December 31, 2014; 19,543,769 shares issued and 19,509,429 shares outstanding at December 31, 2013	568,882	569,028
Retained earnings (accumulated deficit)	15,000	-25,073
Accumulated other comprehensive loss	-258	-2,996
Unearned shares of common stock issued to Employee Stock Ownership Plan (ESOP) at cost: no shares outstanding at December 31, 2014 and 34,340 restricted shares outstanding at December 31, 2013	0	-1,987
Carrying value of shares held in trust for stock related compensation plans	-6,669	-7,063
Liability for common stock issued to deferred, stock related, compensation plans	6,669	7,063
Total stockholders' equity	583,624	538,972
Total liabilities and stockholders' equity	$4,723,899	$4,388,898

CONSOLIDATED_STATEMENTS_OF_FIN1

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
ASSETS
Securities—trading, amortized cost basis	$47,480	$75,150
Securities—available-for-sale, amortized cost basis	411,424	474,960
Securities—held-to-maturity, fair value	$137,608	$103,610
STOCKHOLDERS’ EQUITY
Preferred stock, share par value	$0.01	$0.01
Preferred stock, shares authorized	500,000	500,000
Preferred stock, shares outstanding	0	0
Common stock, share par value	$0.01	$0.01
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	19,571,548	19,543,769
Common stock, shares outstanding	19,571,548	19,509,429
Common stock, shares held in employee trust (ESOP)	0	34,340

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
INTEREST INCOME:
Loans receivable	$177,541	$167,204	$174,322
Mortgage-backed securities	5,779	5,168	4,176
Securities and cash equivalents	7,341	7,340	8,664
Total interest income	190,661	179,712	187,162
INTEREST EXPENSE:
Deposits	7,578	9,737	15,107
FHLB advances	125	99	254
Other borrowings	172	192	758
Junior subordinated debentures	2,914	2,968	3,395
Total interest expense	10,789	12,996	19,514
Net interest income before provision for loan losses	179,872	166,716	167,648
PROVISION FOR LOAN LOSSES	0	0	13,000
Net interest income	179,872	166,716	154,648
OTHER OPERATING INCOME:
Deposit fees and other service charges	30,553	26,581	25,266
Mortgage banking operations	10,249	11,170	13,812
Miscellaneous	2,957	3,484	4,697
Other operating income	43,759	41,235	43,775
Net gain on sale of securities	42	1,022	51
Other-than-temporary impairment recovery (loss)	0	409	-409
Net change in valuation of financial instruments carried at fair value	1,374	-2,278	-16,515
Proposed acquisition termination fee	0	2,954	0
Acquisition bargain purchase gain	9,079	0	0
Total other operating income	54,254	43,342	26,902
OTHER OPERATING EXPENSES:
Salary and employee benefits	89,778	84,388	78,696
Less capitalized loan origination costs	-11,730	-11,227	-10,404
Occupancy and equipment	22,743	21,423	21,812
Information/computer data services	8,131	7,309	6,904
Payment and card processing expenses	11,460	9,870	8,604
Professional services	3,753	3,781	4,411
Advertising and marketing	6,266	6,885	7,215
Deposit insurance	2,415	2,329	3,685
State/municipal business and use taxes	1,437	1,941	2,289
REO operations	-446	-689	3,354
Amortization of core deposit intangibles	1,990	1,941	2,092
Miscellaneous	13,619	12,474	12,795
Total other operating expense, before acquisition related costs	149,416	140,425	141,453
Acquisition related costs	4,325	550	0
Total other operating expenses	153,741	140,975	141,453
Income before provision for (benefit from) income taxes	80,385	69,083	40,097
PROVISION FOR (BENEFIT FROM) INCOME TAXES	26,220	22,528	-24,785
NET INCOME	54,165	46,555	64,882
PREFERRED STOCK DIVIDEND AND DISCOUNT ACCRETION
Preferred stock dividend	0	0	4,938
Preferred stock discount accretion	0	0	3,298
Gain on repurchase of preferred stock	0	0	-2,471
NET INCOME AVAILABLE TO COMMON SHAREHOLDERS	$54,165	$46,555	$59,117
Earnings per common share
Basic (in dollars per share)	$2.80	$2.40	$3.17
Diluted (in dollars per share)	$2.79	$2.40	$3.16
Cumulative dividends declared per common share (in dollars per share)	$0.72	$0.54	$0.04

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
NET INCOME	$54,165	$46,555	$64,882
OTHER COMPREHENSIVE INCOME (LOSS), NET OF INCOME TAXES:
Unrealized holding gain (loss) on securities—available-for-sale arising during the period	4,237	-7,835	28
Income tax benefit (expense) related to securities—available-for-sale unrealized holding gains (losses)	-1,525	2,813	-10
Reclassification for net (gains) losses on securities—available-for-sale realized in earnings	41	-116	38
Income tax benefit (expense) related to securities—available-for-sale realized (gains) losses	-15	42	-14
Amortization of unrealized gain on tax exempt securities transferred from available-for-sale to held-to-maturity	0	0	8
Other comprehensive income (loss)	2,738	-5,096	50
COMPREHENSIVE INCOME	$56,903	$41,459	$64,932

CONSOLIDATED_STATEMENTS_OF_CHA

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (USD $)	Total	Common Stock [Member]	Preferred Stock [Member]	Common Stock Including Additional Paid in Capital [Member]	Retained Earnings (Accumulated Deficit) [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Unearned Restricted ESOP Shares [Member]
In Thousands	USD ($)		USD ($)	USD ($)	USD ($)	USD ($)	USD ($)
Balance, beginning of the period at Dec. 31, 2011	$532,450		$120,702	$531,149	($119,465)	$2,051	($1,987)
Balance, beginning of the period, shares at Dec. 31, 2011		-17,553
Net income	64,882				64,882
Other comprehensive income (loss)	50					50
Accretion of preferred stock discount	0		3,298		-3,298
Repurchase of preferred stock	-124,000		-124,000
Gain on repurchase of preferred stock	2,471				2,471
Accrual of dividends on preferred stock	-4,938				-4,938
Accrual of dividends on common stock	-754				-754
Redemption of unallocated shares upon termination of ESOP, shares		0
Repurchase of shares upon termination of ESOP, shares		0
Issuance of common stock for stockholder reinvestment program, shares		1,815
Proceeds from issuance of common stock for stockholder reinvestment program, net of registration expenses amount	36,317			36,317
Issuance of unvested restricted common stock, net, shares		87
Amortization of share-based compensation related to restricted stock grants, net of shares surrendered	434			434
Amortization of compensation related to stock options	7			7
Net number of shares issued during the period		1,902
Balance, end of the period at Dec. 31, 2012	506,919		0	567,907	-61,102	2,101	-1,987
Balance, end of the period, shares at Dec. 31, 2012	-19,421	-19,455					-34
Net income	46,555				46,555
Other comprehensive income (loss)	-5,097					-5,097
Gain on repurchase of preferred stock	0
Accrual of dividends on preferred stock	0
Accrual of dividends on common stock	-10,526				-10,526
Redemption of unallocated shares upon termination of ESOP, shares		0
Repurchase of shares upon termination of ESOP, shares		0
Issuance of common stock for stockholder reinvestment program, shares		2
Proceeds from issuance of common stock for stockholder reinvestment program, net of registration expenses amount	72			72
Issuance of unvested restricted common stock, net, shares		86
Amortization of share-based compensation related to restricted stock grants, net of shares surrendered	1,049			1,049
Net number of shares issued during the period		88
Balance, end of the period at Dec. 31, 2013	538,972		0	569,028	-25,073	-2,996	-1,987
Balance, end of the period, shares at Dec. 31, 2013	-19,509	-19,543					-34
Net income	54,165				54,165
Other comprehensive income (loss)	2,738					2,738
Gain on repurchase of preferred stock	0
Accrual of dividends on preferred stock	0
Accrual of dividends on common stock	-14,092				-14,092
Redemption of unallocated shares upon termination of ESOP, shares		-34
Redemption of unallocated shares upon termination of ESOP	0			-1,987			1,987
Repurchase of shares upon termination of ESOP, shares		-14
Repurchase of shares upon termination of ESOP	-555			-555
Issuance of common stock for stockholder reinvestment program, shares		3
Proceeds from issuance of common stock for stockholder reinvestment program, net of registration expenses amount	127			127
Issuance of unvested restricted common stock, net, shares		73
Amortization of share-based compensation related to restricted stock grants, net of shares surrendered	2,269			2,269
Net number of shares issued during the period		28
Balance, end of the period at Dec. 31, 2014	$583,624		$0	$568,882	$15,000	($258)	$0
Balance, end of the period, shares at Dec. 31, 2014	-19,571	-19,571					0

CONSOLIDATED_STATEMENTS_OF_CHA1

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Parenthetical) (USD $)	3 Months Ended												12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Stockholders' Equity [Abstract]
Accrual of dividends on common share (dollars per share)	$0.18	$0.18	$0.18	$0.18	$0.15	$0.15	$0.12	$0.12	$0.01	$0.01	$0.01	$0.01	$0.72	$0.54	$0.04

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
OPERATING ACTIVITIES:
Net income	$54,165	$46,555	$64,882
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	8,064	7,457	7,788
Deferred income and expense, net of amortization	1,541	3,200	2,864
Amortization of core deposit intangibles	1,990	1,941	2,092
Gain on sale of securities, net	-42	-1,022	-51
Other-than-temporary impairment (recovery) loss	0	-409	409
Net change in valuation of financial instruments carried at fair value	-1,374	2,278	16,515
Purchases of securities—trading	-2,387	-32,413	-5,408
Proceeds from sales of securities—trading	2,387	34,308	5,073
Principal repayments and maturities of securities—trading	27,709	6,509	15,880
Bargain purchase gain on acquisition	-9,079	0	0
Decrease (increase) in deferred taxes	2,871	7,528	-35,007
Increase (decrease) in current taxes payable	11,771	-10,818	1,089
Equity-based compensation	2,269	1,049	440
Increase in cash surrender value of BOLI	-1,788	-1,999	-2,554
Gain on sale of loans, net of capitalized servicing rights	-6,080	-6,498	-10,154
Gain on disposal of real estate held for sale and property and equipment	-1,076	-2,521	-4,614
Provision for losses on loans and real estate held for sale	36	785	18,178
Origination of loans held for sale	-361,859	-427,542	-503,492
Proceeds from sales of loans held for sale	367,888	443,225	504,734
Net change in:
Other assets	-2,310	19,426	-818
Other liabilities	3,370	4,327	3,569
Net cash provided from operating activities	98,066	95,366	81,415
INVESTING ACTIVITIES:
Purchases of securities—available-for-sale	-58,705	-197,911	-413,482
Principal repayments and maturities of securities—available-for-sale	62,520	84,424	389,414
Proceeds from sales of securities—available-for-sale	56,267	103,274	13,282
Purchases of securities—held-to-maturity	-38,961	-26,221	-23,007
Principal repayments and maturities of securities—held-to-maturity	9,194	9,788	11,806
Loan originations, net of principal repayments	-144,152	-167,085	45,979
Purchases of loans and participating interest in loans	-194,381	-48,725	-18,477
Proceeds from sales of other loans	11,277	19,305	9,851
Net cash received from acquisitions	127,557	6,809	0
Purchases of property and equipment, net of sales	-5,935	-8,211	-5,613
Proceeds from sale of real estate held for sale, net	4,923	16,944	40,965
Proceeds from FHLB stock repurchase program	8,354	1,315	666
Other	-2,025	-127	1,095
Net cash provided from (used by) investing activities	-164,067	-206,421	52,479
FINANCING ACTIVITIES
Increase in deposits, net	68,938	51,417	82,150
Advances, net of (repayments) of FHLB borrowings	4,992	16,993	-6
Increase (decrease) in other borrowings, net	-5,871	6,423	-75,495
Cash dividends paid	-13,462	-7,799	-6,470
Cash proceeds from issuance of stock for stockholder reinvestment plan	127	72	36,317
Redemption of preferred stock	0	0	-121,528
Net cash provided from (used by) financing activities	54,724	67,106	-85,032
NET INCREASE (DECREASE) IN CASH AND DUE FROM BANKS	-11,277	-43,949	48,862
CASH AND DUE FROM BANKS, BEGINNING OF YEAR	137,349	181,298	132,436
CASH AND DUE FROM BANKS, END OF YEAR	126,072	137,349	181,298
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Interest paid in cash	10,929	13,362	20,712
Taxes paid in cash	13,047	22,828	9,631
NON-CASH INVESTING AND FINANCING TRANSACTIONS:
Loans, net of discounts, specific loss allowances and unearned income, transferred to real estate owned and other repossessed assets	3,493	3,448	14,070
ACQUISITIONS (Note 4):
Assets acquired	221,206	8,710	0
Liabilities assumed	$212,127	$8,710	$0

BASIS_OF_PRESENTATION_AND_SUMM

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
	Nature of Business:  Banner Corporation (Banner or the Company) is a bank holding company incorporated in the State of Washington.  The Company is primarily engaged in the business of planning, directing and coordinating the business activities of two wholly-owned subsidiaries, Banner Bank and Islanders Bank.  Banner Bank is a Washington-chartered commercial bank that conducts business from its main office in Walla Walla, Washington and, as of December 31, 2014, its 90 branch offices and ten loan production offices located in Washington, Oregon and Idaho.  Islanders Bank is also a Washington-chartered commercial bank that conducts business from three locations in San Juan County, Washington.  Banner Corporation is subject to regulation by the Board of Governors of the Federal Reserve System.  Banner Bank and Islanders Bank (the Banks) are subject to regulation by the Washington State Department of Financial Institutions, Division of Banks (DFI) and the Federal Deposit Insurance Corporation (the FDIC).
	The Company’s operating results depend primarily on its net interest income, which is the difference between interest income on interest-earning assets, consisting of loans and investment securities, and interest expense on interest-bearing liabilities, composed primarily of customer deposits, Federal Home Loan Bank (FHLB) advances, other borrowings and junior subordinated debentures.  Net income also is affected by the level of the Company’s other operating income, including deposit fees and service charges, loan origination and servicing fees, and gains and losses on the sale of loans and securities, as well as non-interest operating expenses, provisions for loan losses and income tax provisions.  In addition, net income is affected by the net change in the value of certain financial instruments carried at fair value.
	Principles of Consolidation:  The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries.  All material intercompany transactions, profits and balances have been eliminated.
	Subsequent Events: The Company has evaluated events and transactions subsequent to December 31, 2014 for potential recognition or disclosure through March 16, 2015, which is the date the financial statements were available to be issued.
	Business Combinations: Business combinations are accounted for using the acquisition method of accounting. Under the acquisition method of accounting, assets acquired and liabilities assumed are recorded at estimated fair value at the date of acquisition. Any difference in purchase consideration over the fair value of assets acquired and liabilities assumed results in the recognition of goodwill should purchase consideration exceed net estimated fair values, or a bargain purchase gain, should estimated fair values exceed purchase consideration. Expenses incurred in connection with a business combination are expensed as incurred. Changes in deferred tax asset valuation allowances acquired tax uncertainties after the measurement period are recognized in net income.
	Use of Estimates:  In the opinion of management, the accompanying consolidated statements of financial condition and related consolidated statements of operations, comprehensive income (loss), changes in stockholders’ equity and cash flows reflect all adjustments (which include reclassification and normal recurring adjustments) that are necessary for a fair presentation in conformity with U.S. Generally Accepted Accounting Principles (GAAP).  The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect amounts reported in the financial statements.  Various elements of the Company’s accounting policies, by their nature, are inherently subject to estimation techniques, valuation assumptions and other subjective assessments.  In particular, management has identified several accounting policies that, due to the judgments, estimates and assumptions inherent in those policies, are critical to an understanding of Banner’s financial statements.  These policies relate to (i) the methodology for the recognition of interest income, (ii) determination of the provision and allowance for loan and lease losses, (iii) the valuation of financial assets and liabilities recorded at fair value, including other-than-temporary impairment (OTTI) losses, (iv) the valuation of intangibles, such as core deposit intangibles and mortgage servicing rights, (v) the valuation of real estate held for sale and (vi) the valuation of or recognition of deferred tax assets and liabilities.  These policies and judgments, estimates and assumptions are described in greater detail in subsequent notes to the consolidated financial statements and Management’s Discussion and Analysis of Financial Condition and Results of Operations (Critical Accounting Policies) in this Annual Report on Form 10-K for the year ended December 31, 2014 filed with the Securities and Exchange Commission (SEC).  Management believes that the judgments, estimates and assumptions used in the preparation of the financial statements are appropriate based on the factual circumstances at the time.  However, given the sensitivity of the financial statements to these critical accounting policies, the use of other judgments, estimates and assumptions could result in material differences in the Company’s results of operations or financial condition.  Further, subsequent changes in economic or market conditions could have a material impact on these estimates and the Company’s financial condition and operating results in future periods.
	Securities: Securities are classified as held-to-maturity when the Company has the ability and positive intent to hold them to maturity.  Securities classified as available-for-sale are available for future liquidity requirements and may be sold prior to maturity.  Securities classified as trading are also available for future liquidity requirements and may be sold prior to maturity.  Purchase premiums and discounts are recognized in interest income using the interest method over the terms of the securities.  Securities classified as held-to-maturity are carried at cost, adjusted for amortization of premiums and accretion of discounts to maturity and, if appropriate, any other-than-temporary impairment losses.  Securities classified as available-for-sale are recorded at fair value.  Unrealized holding gains and losses on securities classified as available-for-sale are excluded from earnings and are reported net of tax as accumulated other comprehensive income (loss), a component of stockholders’ equity, until realized.  Securities classified as trading are also recorded at fair value.  Unrealized holding gains and losses on securities classified as trading are included in earnings.  (See Note 22 for a more complete discussion of accounting for the fair value of financial instruments.)  Declines in the fair value of securities below their cost that are deemed to be other-than-temporary are recognized in earnings as realized losses.  Realized gains and losses on sale are computed on the specific identification method and are included in earnings on the trade date sold.
	The Company reviews investment securities on an ongoing basis for the presence of OTTI or permanent impairment, taking into consideration current market conditions, fair value in relationship to cost, extent and nature of the change in fair value, issuer rating changes and trends, whether the Company intends to sell a security or if it is likely that it will be required to sell the security before recovery of the amortized cost basis of the investment, which may be maturity, and other factors.
	For debt securities, if the Company intends to sell the security or it is likely that the Company will be required to sell the security before recovering its cost basis, the entire impairment loss would be recognized in earnings as an OTTI.  If the Company does not intend to sell the security and it is not likely that the Company will be required to sell the security but the Company does not expect to recover the entire amortized cost basis of the security, only the portion of the impairment loss representing credit losses would be recognized in earnings.  The credit loss on a security is measured as the difference between the amortized cost basis and the present value of the cash flows expected to be collected.  Projected cash flows are discounted by the original or current effective interest rate depending on the nature of the security being measured for potential OTTI.  The remaining impairment related to all other factors, the difference between the present value of the cash flows expected to be collected and fair value, is recognized as a charge to other comprehensive income (OCI).  Impairment losses related to all other factors are presented as separate categories within OCI.
	For investment securities transferred from held-to-maturity to available-for-sale, unrealized gains or losses from the time of transfer are accreted or amortized over the remaining life of the debt security based on the amount and timing of future estimated cash flows.  The accretion or amortization of the amount recorded in OCI increases the carrying value of the investment and does not affect earnings.
	Investment in FHLB Stock: At December 31, 2014, the Company had $27.0 million in FHLB stock, compared to $35.4 million at December 31, 2013. The Banks' investments in FHLB stock are generally viewed as a long-term investment and are carried at par value ($100 per share), which reasonably approximates its fair value. FHLB stock does not have a readily determinable fair value. Ownership of FHLB stock is restricted to the FHLB and member institutions and can only be purchased and redeemed at par. As members of the FHLB system, the Banks are required to maintain a minimum level of investment in FHLB stock based on specific percentages of their outstanding FHLB advances.
	Management periodically evaluates FHLB stock for impairment. Management's determination of whether these investments are impaired is based on its assessment of the ultimate recoverability of cost rather than by recognizing temporary declines in value. The determination of whether a decline affects the ultimate recoverability of cost is influenced by criteria such as (1) the significance of any decline in net assets of the FHLB as compared to the capital stock amount for the FHLB and the length of time this situation has persisted, (2) commitments by the FHLB to make payments required by law or regulation and the level of such payments in relation to the operating performance of the FHLB, (3) the impact of legislative and regulatory changes on institutions and, accordingly, the customer base of the FHLB, and (4) the liquidity position of the FHLB.
	The FHLB of Seattle announced that it had a risk-based capital deficiency under the regulations of the Federal Housing Finance Agency (the FHFA), its primary regulator, as of December 31, 2008, and that it would suspend future dividends and the repurchase and redemption of outstanding common stock. The FHLB of Seattle announced on September 7, 2012 that the FHFA now considers the FHLB of Seattle to be adequately capitalized. Dividends on, or repurchases of, the FHLB of Seattle stock continue to require consent of the FHFA. The FHFA subsequently approved the repurchase of portions of FHLB of Seattle stock, and as of December 31, 2014, the FHLB had repurchased $9.7 million of the Banks' stock. For the years ended December 31, 2012 and 2011, the Banks did not receive any dividend income on FHLB stock. The FHLB continued to progress and on November 11, 2013 an Amended Consent Arrangement was agreed to with the FHLB's regulator. During the year ended December 31, 2013, the FHLB of Seattle paid two dividends, one in August and one in October, totaling $18,000 in dividend income for that year. During the year ended December 31, 2014, the FHLB of Seattle paid four dividends totaling $34,000 in dividend income for the Banks for the year.
	On September 25, 2014, the FHLB Seattle and FHLB Des Moines announced a proposed merger. Under this proposal, each of our Banks would become a member of FHLB Des Moines and all shares of our FHLB Seattle stock would convert to equal shares of FHLB Des Moines stock. If the merger is terminated by either the FHLB Des Moines or the FHLB Seattle, the terminating FHLB must pay $57 million in termination fees. If the FHLB Seattle were to terminate the agreement, this could result in significant impairment to our investment in the FHLB Seattle, potentially decreasing our earnings and shareholders' equity. The Company will continue to monitor the financial condition of the FHLB of Seattle as it relates to, among other things, the recoverability of Banner's investment. Based on the above, the Company has determined there is not any impairment on the FHLB stock investment as of December 31, 2014.
	Loans Receivable:  The Banks originate residential mortgage loans for both portfolio investment and sale in the secondary market.  At the time of origination, mortgage loans are designated as held for sale or held for investment.  Loans held for sale are stated at lower of cost or estimated market value determined on an aggregate basis.  Net unrealized losses on loans held for sale are recognized through a valuation allowance by charges to income.  The Banks also originate construction and land development, commercial and multifamily real estate, commercial business, agricultural and consumer loans for portfolio investment.  Loans receivable not designated as held for sale are recorded at the principal amount outstanding, net of allowance for loan losses, deferred fees, discounts and premiums.  Premiums, discounts and deferred loan fees are amortized to maturity using the level-yield methodology.
	Some of the Company’s loans are reported as troubled debt restructures (TDRs).  Loans are reported as restructured when the Bank grants a concession(s) to a borrower experiencing financial difficulties that it would not otherwise consider.  Examples of such concessions include forgiveness of principal or accrued interest, extending the maturity date(s) or providing a lower interest rate than would be normally available for a transaction of similar risk.  As a result of these concessions, loans identified as TDRs are impaired as the Bank will not collect all amounts due, both principal and interest, in accordance with the terms of the original loan agreement.  TDRs are accounted for in accordance with the Banks’ impaired loan accounting policies.
	Income Recognition on Nonaccrual and Impaired Loans:  Interest on loans and securities is accrued as earned unless management doubts the collectability of the asset or the unpaid interest.  Interest accruals on loans are generally discontinued when loans become 90 days past due for payment of interest and the loans are then placed on nonaccrual status.  All previously accrued but uncollected interest is deducted from interest income upon transfer to nonaccrual status.  For any future payments collected, interest income is recognized only upon management’s assessment that there is a strong likelihood that the full amount of a loan will be repaid or recovered.  A loan may be put on nonaccrual status sooner than this policy would dictate if, in management’s judgment, the interest may be uncollectable.  While less common, similar interest reversal and nonaccrual treatment is applied to investment securities if their ultimate collectability becomes questionable.
	Provision and Allowance for Loan Losses:  The provision for loan losses reflects the amount required to maintain the allowance for losses at an appropriate level based upon management’s evaluation of the adequacy of general and specific loss reserves.  The Company maintains an allowance for loan losses consistent in all material respects with generally accepted accounting principles.  The Company has established systematic methodologies for the determination of the adequacy of the Company’s allowance for loan losses.  The methodologies are set forth in a formal policy and take into consideration the need for a general valuation allowance as well as specific allowances that are tied to individual problem loans.  The Company increases its allowance for loan losses by charging provisions for probable loan losses against its income and values impaired loans consistent with accounting guidelines.
	The allowance for losses on loans is maintained at a level sufficient to provide for estimated losses based on evaluating known and inherent risks in the loan portfolio and upon the Company’s continuing analysis of the factors underlying the quality of the loan portfolio.  These factors include, among others, changes in the size and composition of the loan portfolio, delinquency rates, actual loan loss experience, current and anticipated economic conditions, detailed analysis of individual loans for which full collectability may not be assured, and determination of the existence and realizable value of the collateral and guarantees securing the loans.  Realized losses related to specific assets are applied as a reduction of the carrying value of the assets and charged immediately against the allowance for loan loss reserve.  Recoveries on previously charged off loans are credited to the allowance.  The reserve is based upon factors and trends identified by Banner at the time financial statements are prepared.  Although the Company uses the best information available, future adjustments to the allowance may be necessary due to economic, operating, regulatory and other conditions beyond the Company’s control.  The adequacy of general and specific reserves is based on a continuing evaluation of the pertinent factors underlying the quality of the loan portfolio as well as individual review of certain large balance loans.  Large groups of smaller-balance homogeneous loans are collectively evaluated for impairment.  Loans that are collectively evaluated for impairment include residential real estate and consumer loans and, as appropriate, smaller balance non-homogeneous loans.  Larger balance non-homogeneous residential construction and land, commercial real estate, commercial business loans and unsecured loans are individually evaluated for impairment.  Loans are considered impaired when, based on current information and events, the Company determines that it is probable that it will be unable to collect all amounts due according to the contractual terms of the loan agreement.  Factors involved in determining impairment include, but are not limited to, the financial condition of the borrower and the value of the underlying collateral.  Impaired loans are measured based on the present value of expected future cash flows discounted at the loan’s effective interest rate or, as a practical expedient, at the loan’s observable market price or the fair value of collateral if the loan is collateral dependent.  Subsequent changes in the value of impaired loans are included within the provision for loan losses in the same manner in which impairment initially was recognized or as a reduction in the provision that would otherwise be reported.
	The Company’s methodology for assessing the appropriateness of the allowance consists of several key elements, which include specific allowances, an allocated formula allowance and an unallocated allowance.  Losses on specific loans are provided for when the losses are probable and estimable.  General loan loss reserves are established to provide for inherent loan portfolio risks not specifically provided for.  The level of general reserves is based on analysis of potential exposures existing in the loan portfolio including evaluation of historical trends, current market conditions and other relevant factors identified by us at the time the financial statements are prepared.  The formula allowance is calculated by applying loss factors to outstanding loans, excluding those loans that are subject to individual analysis for specific allowances.  Loss factors are based on the Company’s historical loss experience adjusted for significant environmental considerations, including the experience of other banking organizations, which in the judgment of management affects the collectability of the portfolio as of the evaluation date.  The unallocated allowance is based upon the Company’s evaluation of various factors that are not directly measured in the determination of the formula and specific allowances.
	While the Company believes the estimates and assumptions used in the determination of the adequacy of the allowance are reasonable, there can be no assurance that such estimates and assumptions will not be proved incorrect in the future, or that the actual amount of future provisions will not exceed the amount of past provisions or that any increased provisions that may be required will not adversely impact the financial condition and results of operations of the Company.  In addition, the determination of the amount of the allowance for loan losses is subject to review by bank regulators as part of the routine examination process, which may result in the adjustment of reserves based upon their judgment of information available to them at the time of their examination.
	Loan Origination and Commitment Fees:  Loan origination fees, net of certain specifically defined direct loan origination costs, are deferred and recognized as an adjustment of the loans’ interest yield using the level-yield method over the contractual term of each loan adjusted for actual loan prepayment experience.  Net deferred fees or costs related to loans held for sale are recognized in income at the time the loans are sold.  Loan commitment fees are deferred until the expiration of the commitment period unless management believes there is a remote likelihood that the underlying commitment will be exercised, in which case the fees are amortized to fee income using the straight-line method over the commitment period.  If a loan commitment is exercised, the deferred commitment fee is accounted for in the same manner as a loan origination fee.  Deferred commitment fees associated with expired commitments are recognized as fee income.
	Real Estate Held for Sale: Property acquired by foreclosure or deed in lieu of foreclosure is recorded at the lower of the estimated fair value of the property, less expected selling costs, or the carrying value of the defaulted loan.  Development and improvement costs relating to the property are capitalized while direct holding costs are expensed.  The carrying value of the property is periodically evaluated by management and, if necessary, allowances are established to reduce the carrying value to net realizable value.  Gains or losses at the time the property is sold are charged or credited to operations in the period in which they are realized.  The amounts the Banks will ultimately recover from real estate held for sale may differ substantially from the carrying value of the assets because of market factors beyond the Banks’ control or because of changes in the Banks’ strategies for recovering the investment.
	Property and Equipment:  The provision for depreciation is based upon the straight-line method applied to individual assets and groups of assets acquired in the same year at rates adequate to charge off the related costs over their estimated useful lives:
	Buildings and leased improvements	10–30 years
	Furniture and equipment	3–10 years
	Routine maintenance, repairs and replacement costs are expensed as incurred.  Expenditures which significantly increase values or extend useful lives are capitalized.  The Company reviews buildings, leasehold improvements and equipment for impairment whenever events or changes in circumstances indicate that the undiscounted cash flows for the property are less than its carrying value.  If identified, an impairment loss is recognized through a charge to earnings based on the fair value of the property.
	Other Intangible Assets:  Other intangible assets consist primarily of core deposit intangibles (CDI), which are amounts recorded in business combinations or deposit purchase transactions related to the value of transaction-related deposits and the value of the customer relationships associated with the deposits.  Core deposit intangibles are being amortized on an accelerated basis over a weighted average estimated useful life of three to eight years.  These assets are reviewed at least annually for events or circumstances that could impact their recoverability.  These events could include loss of the underlying core deposits, increased competition or adverse changes in the economy.  To the extent other identifiable intangible assets are deemed unrecoverable, impairment losses are recorded in other non-interest expense to reduce the carrying amount of the assets.
	Mortgage Servicing Rights: Servicing assets are recognized as separate assets when rights are acquired through purchase or sale of loans.  Generally, purchased servicing rights are capitalized at the cost to acquire the rights.  For sales of mortgage loans, the value of the servicing right is estimated and capitalized.  Fair value is based on market prices for comparable mortgage servicing contracts.  Capitalized servicing rights are reported in other assets and are amortized into non-interest income in proportion to, and over the period of, the estimated future net servicing income of the underlying financial assets.
	Servicing assets are evaluated for impairment based upon the fair value of the rights as compared to amortized cost.  Impairment is determined by stratifying rights into tranches based on predominant risk characteristics for the underlying loans, such as interest rate, balance outstanding, loan type, age and remaining term, and investor type.  Impairment is recognized through a valuation allowance for an individual tranche, to the extent that fair value is less than the capitalized amount for the tranche.  If the Company later determines that all or a portion of the impairment no longer exists for a particular tranche, a reduction of the allowance may be recorded as an increase to income.
	Servicing fee income is recorded for fees earned for servicing loans and is reflected in mortgage banking operations on the consolidated statement of operations.  The fees are based on a contractual percentage of the outstanding principal or a fixed amount per loan and are recorded as income when earned.  The amortization of mortgage servicing rights is netted against loan servicing fee income.
	Bank-Owned Life Insurance (BOLI):  The Banks have purchased, or acquired through mergers, life insurance policies in connection with the implementation of certain executive supplemental income, salary continuation and deferred compensation retirement plans.  These policies provide protection against the adverse financial effects that could result from the death of a key employee and provide tax-exempt income to offset expenses associated with the plans.  It is the Banks’ intent to hold these policies as a long-term investment; however, there may be an income tax impact if the Bank chooses to surrender certain policies.  Although the lives of individual current or former management-level employees are insured, the Banks are the respective owners and sole or partial beneficiaries.  At December 31, 2014 and 2013, the cash surrender value of these policies was $63.8 million and $61.9 million, respectively.
	Derivative Instruments:  Derivatives include “off-balance-sheet” financial products, the value of which is dependent on the value of underlying financial assets, such as stock, bonds, foreign currency, or a reference rate or index.  Such derivatives include “forwards,” “futures,” “options” or “swaps.”  As a result of the 2007 acquisition of F&M Bank, Banner Bank became a party to approximately $23 million ($13 million as of December 31, 2014) in notional amounts of interest rate swaps.  Some of these swaps serve as hedges to an equal amount of fixed rate loans which include market value prepayment penalties that mirror the provision of the specifically matched interest rate swaps.  In addition, in 2011 we began actively marketing interest rate swaps to certain loan customers in connection with longer-term floating rate loans, allowing them to effectively fix their loan interest rates.  These customer swaps are matched with third party swaps with qualified broker/dealer or banks to offset the risk.  As of December 31, 2014, we had $129 million in notional amounts of these customer interest rate swaps outstanding, with an equal amount of offsetting third party swaps also in place.  The fair value adjustments for these swaps and the related loans are reflected in other assets or other liabilities as appropriate, and in the carrying value of the related loans.
	Further, as a part of its mortgage banking activities, the Company issues “rate lock” commitments to borrowers and obtains offsetting “best efforts” delivery commitments from purchasers of loans. The Company also uses forward contracts for the sale of mortgage-backed securities and mandatory delivery commitments for the sale of loans to hedge "rate lock" commitments and loans held for sale.  The commitments to originate mortgage loans held for sale and the related delivery contracts are considered derivatives.  The Company recognizes all derivatives as either assets or liabilities in the balance sheet and requires measurement of those instruments at fair value through adjustments to current earnings.  None of these residential mortgage loan related derivatives are designated as hedging instruments for accounting purposes.  Rather, they are accounted for as free-standing derivatives, or economic hedges, and the Company reports changes in fair values of its derivatives in current period net income.  The fair value of the derivative loan commitments is estimated using the present value of expected future cash flows.  Assumptions used include rate assumptions based on historical information, current mortgage interest rates, the stage of completion of the underlying application and underwriting process, the time remaining until the expiration of the derivative loan commitment, and the expected net future cash flows related to the associated servicing of the loan (see Note 28 for a more complete discussion of derivatives and hedging).
	Transfers of Financial Assets:  Transfers of financial assets are accounted for as sales when control over the assets has been surrendered.  Control over transferred assets is deemed to be surrendered when (1) the assets have been isolated from the Banks, (2) the transferee obtains the right (free of conditions that constrain it from taking advantage of that right) to pledge or exchange the transferred assets, and (3) the Banks do not maintain effective control over the transferred assets through an agreement to repurchase them before their maturity.
	Advertising Expenses:  Advertising costs are expensed as incurred.  Costs related to production of advertising are considered incurred when the advertising is first used.
	Income Taxes:  The Company files a consolidated income tax return including all of its wholly-owned subsidiaries on a calendar year basis.  Income taxes are accounted for using the asset and liability method.  Under this method, a deferred tax asset or liability is determined based on the enacted tax rates which will be in effect when the differences between the financial statement carrying amounts and tax bases of existing assets and liabilities are expected to be reported in the Company’s income tax returns.  The effect on deferred taxes of a change in tax rates is recognized in income in the period of change. A valuation allowance is recognized as a reduction to deferred tax assets when management determines it is more likely than not that deferred tax assets will not be available to offset future income tax liabilities.
	Accounting standards for income taxes prescribe a recognition threshold and measurement process for financial statement recognition and measurement of uncertain tax positions taken or expected to be taken in a tax return, and also provides guidance on the de-recognition of previously recorded benefits and their classification, as well as the proper recording of interest and penalties, accounting in interim periods, disclosures and transition.  The Company periodically reviews its income tax positions based on tax laws and regulations and financial reporting considerations, and records adjustments as appropriate.  This review takes into consideration the status of current taxing authorities’ examinations of the Company’s tax returns, recent positions taken by the taxing authorities on similar transactions, if any, and the overall tax environment.
	As of December 31, 2014, the Company had an insignificant amount of unrecognized tax benefits for uncertain tax positions, none of which would materially affect the effective tax rate if recognized. The Company does not anticipate that the amount of unrecognized tax benefits will significantly increase or decrease in the next twelve months. The Company’s policy is to recognize interest and penalties on unrecognized tax benefits in the income tax expense. The amount of interest and penalties accrued for the years ended December 31, 2014 and 2013 is immaterial. The Company files consolidated income tax returns in Oregon and Idaho and for federal purposes. The Company has tax years 2011–2013 open for tax examination under the statute of limitation provisions of the Internal Revenue Code of 1986 (Code). Tax years 2008–2010 are not open for assessment of additional tax, but remain open for adjustment to the amount of Net Operating Losses (NOLs), credit, and other carryforwards utilized in open years or to be utilized in the future.
	Employee Stock Ownership Plan: In 1995, the Company established an ESOP and related trust for eligible employees of Banner Bank as of January 1, 1995 and eligible employees of the Banks or Company employed after such date. No ESOP contributions were made for the years ended December 31, 2014, 2013 or 2012. On December 17, 2013, the Company's Board of Directors elected to terminate the ESOP effective January 1, 2014. Termination of the ESOP had no impact on the net equity position of the Company or its current and future operating results.
	Share-Based Compensation:  At December 31, 2014, the Company had the following share-based employee/director compensation plans as approved by the shareholders:  the 1998 Stock Option Plan, and the 2001 Stock Option Plan (collectively, the SOPs), the 2012 Restricted Stock and Incentive Bonus Plan, the 2006 Banner Corporation Long-Term Incentive Plan and the Banner Corporation 2014 Omnibus Incentive Plan.  In addition, in 2011 and 2010, the Company made restricted stock grants to Mark Grescovich, President and CEO of Banner Bank and Banner Corporation, in accordance with his employment agreement.
	The Company has adopted the fair value recognition for recognizing stock compensation expense, using the modified-prospective-transition method.  Under that method, compensation costs are recognized based upon grant date fair value.  This method requires the cash flows resulting from the tax benefits of tax deductions in excess of the compensation cost recognized for those options (excess tax benefits) to be classified as financing cash flows.  The restricted stock grants value shares awarded at their fair value, which is their intrinsic value on the date of the award grant.  The expense of the award grants are accrued ratably over the vesting period from the date of each award. These plans are described more fully in Note 16.
	The Banner Corporation Long-Term Incentive Plan (the Plan) was initiated in June 2006.  The Plan is an account-based type of benefit, the value of which is directly related to changes in the value of the Company’s common stock (the excess of the fair market value of a share of the Company’s common stock on the date of vesting over the fair market value of such share on the date granted) plus, for certain awards, dividends declared on the Company’s common stock and changes in Banner Bank’s average earnings rate.  Awards granted through the Plan are considered stock appreciation rights (SARs) and are included in deferred compensation.  The Company remeasures the fair value of a SAR each reporting period until the award is settled and compensation expense is recognized each reporting period for changes in the SAR’s fair value and vesting.
	Banner Corporation 2014 Omnibus Incentive Plan: The 2014 Plan was approved by shareholders on April 22, 2014. The 2014 Plan provides for the grant of incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock, restricted stock units, performance shares, performance units, other stock-based awards and other cash awards, and provides for vesting requirements which may include time-based or performance-based conditions. The Company has reserved 900,000 shares of its common stock for issuance under the 2014 Plan in connection with exercise of awards. As of December 31, 2014, 9,352 shares had been granted to directors under the 2014 Omnibus Incentive Plan.
	Comprehensive Income (Loss):  Accounting principles generally require that recognized revenue, expenses, gains and losses be included in net income.  In addition, certain changes in assets and liabilities, such as unrealized gains and losses on available-for-sale securities, are reported as a separate component of the equity section of the Consolidated Statements of Financial Condition, and such items, along with net income, are components of comprehensive income (loss) which is reported in the Consolidated Statements of Comprehensive Income (Loss).
	Business Segments:  The Company is managed by legal entity and not by lines of business.  Each of the Banks is a community oriented commercial bank chartered in the State of Washington.  The Banks’ primary business is that of a traditional banking institution, gathering deposits and originating loans for portfolio in its respective primary market areas.  The Banks offer a wide variety of deposit products to their consumer and commercial customers.  Lending activities include the origination of real estate, commercial/agriculture business and consumer loans.  Banner Bank is also an active participant in the secondary market, originating residential loans for sale on both a servicing released and servicing retained basis.  In addition to interest income on loans and investment securities, the Banks receive other income from deposit service charges, loan servicing fees and from the sale of loans and investments.  The performance of the Banks is reviewed by the Company’s executive management and Board of Directors on a monthly basis.  All of the executive officers of the Company are members of Banner Bank’s management team.
	Generally Accepted Accounting Principles establish standards to report information about operating segments in annual financial statements and require reporting of selected information about operating segments in interim reports to stockholders.  The Company has determined that its current business and operations consist of a single business segment.
	Reclassification:  Certain reclassifications have been made to the prior years’ consolidated financial statements and/or schedules to conform to the current year’s presentation.  These reclassifications may have affected certain reported amounts and ratios for the prior periods.  These reclassifications had no effect on retained earnings (accumulated deficit) or net income as previously presented and the effect of these reclassifications is considered immaterial.

RECENT_DEVELOPMENTS_AND_SIGNIF

RECENT DEVELOPMENTS AND SIGNIFICANT EVENTS	12 Months Ended
	Dec. 31, 2014
Recent Developments and Significant Events [Abstract]
RECENT DEVELOPMENTS AND SIGNIFICANT EVENTS	RECENT DEVELOPMENTS AND SIGNIFICANT EVENTS
	Proposed Acquisition of AmericanWest Bank: On November 5, 2014, we announced the execution of a definitive agreement to purchase Starbuck Bancshares, Inc. (Starbuck) the bank holding company of AmericanWest Bank (AmericanWest), a Washington state chartered commercial bank headquartered in Spokane, Washington, with 94 branches serving markets in Washington, Oregon, Idaho, California and Utah. The merger agreement provides that Starbuck will merge with and into a wholly-owned subsidiary of the Company. Immediately following the merger, Starbuck's wholly owned bank subsidiary, AmericanWest will merge with Banner Bank. At September 30, 2014, AmericanWest had $4.1 billion in assets, $2.5 billion in net loans, $3.3 billion in deposits and members' equity of $561.3 million excluding AmericanWest's recent acquisition of Greater Sacramento Bancorp, which was completed on February 6, 2015. At September 30, 2014, Greater Sacramento Bancorp had $481 million in assets, $410 million in deposits and stockholders' equity of $39 million. The merged banks will operate under the Banner Bank brand. Under the terms of the agreement, the aggregate consideration to be received by AmericanWest equity holders will consist of a fixed amount of 13.23 million shares of Banner common stock and $130.0 million in cash. Upon completion of the transaction, such shares will represent an approximately 38.8% pro forma ownership interest in Banner. The merger is expected to close late in the second quarter or early in the third quarter of 2015 and is subject to approval by regulatory agencies, obtaining the requisite shareholder approval to issue the shares necessary to complete the transaction, as well as other customary closing conditions. Upon completion of the AmericanWest merger, Banner Bank will have more than 190 locations in five western states, a significantly expanded customer base and meaningfully increased business opportunities.
	Shareholder Equity Transactions
	Restricted Stock Grants: Under the 2012 Restricted Stock Plan, which was approved on April 24, 2012, the Company is authorized to issue up to 300,000 shares of its common stock to provide a means for attracting and retaining highly skilled officers of Banner Corporation and its affiliates. Shares granted under the Plan have a minimum vesting period of three years. The Plan will continue in effect for a term of ten years, after which no further awards may be granted. Vesting requirements may include time-based conditions, performance-based conditions, or market-based conditions. The 2012 Restricted Stock Plan was amended on April 23, 2013 to provide for the ability to grant (1) cash-denominated incentive-based awards payable in cash or common stock, including those that are eligible to qualify as qualified performance-based compensation for the purposes of Section 162(m) of the Code and (2) restricted stock awards that qualify as qualified performance-based compensation for the purposes of Section 162(m) of the Code. As of December 31, 2014, the Company had granted 266,778 shares of restricted stock from the 2012 Restricted Stock Plan, of which 81,241 shares had vested and 185,537 shares remain unvested.
	Omnibus Incentive Plan: On January 28, 2014, the Company's board of directors unanimously adopted, and on April 22, 2014 the Company's shareholders approved, the Banner Corporation 2014 Omnibus Incentive Plan (2014 Plan). The purpose of the 2014 Plan is to promote the success and enhance the value of Banner by linking the personal interests of employees and directors with those of Banner's shareholders. The 2014 Plan is further intended to provide flexibility to Banner in its ability to motivate, attract, and retain the services of employees and directors upon whose judgment, interest and special effort Banner depends. The 2014 Plan also allows performance-based compensation to be provided in a manner that exempts such compensation from the deduction limits imposed by Section 162(m) of the Internal Revenue Code.
	Common Stock Repurchase Program: On March 26, 2014, the Company announced that its Board of Directors had authorized the repurchase of up to 978,826 shares of the Company's common stock, or 5% of the Company's outstanding shares. Under the plan, shares may be repurchased by the Company in open market purchases. The extent to which the Company repurchases its shares and the timing of such repurchases will depend upon market conditions and other corporate considerations.

ACCOUNTING_STANDARDS_RECENTLY_

ACCOUNTING STANDARDS RECENTLY ADOPTED OR ISSUED	12 Months Ended
	Dec. 31, 2014
Accounting Changes and Error Corrections [Abstract]
ACCOUNTING STANDARDS RECENTLY ADOPTED OR ISSUED	ACCOUNTING STANDARDS RECENTLY ISSUED OR ADOPTED
	Unrecognized Tax Benefits
	In July 2013, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2013-11, Presentation of an Unrecognized Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. This ASU requires an unrecognized tax benefit to be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward. An exception exists to the extent that a net operating loss carryforward, a similar tax loss, or a tax credit carryforward is not available at the reporting date under the tax law of the applicable jurisdiction to settle any additional income taxes that would result from the disallowance of a tax position or the tax of the applicable jurisdiction does not require the entity to use, and entity does not intend to use, the deferred tax asset for such a purpose, the unrecognized tax benefit should be presented in the financial statements as a liability and should not be combined with deferred tax assets. ASU No. 2013-11 is effective for fiscal years and interim periods beginning after December 15, 2013. The Company adopted the provisions of ASU No. 2013-11 effective January 1, 2014. The adoption of this guidance did not have a material effect on the Company's consolidated financial statements.
	Investing in Qualified Affordable Housing Projects
	In January 2014, FASB issued ASU No. 2014-01, Accounting for Investments in Qualified Affordable Housing Projects. The objective of this ASU is to provide guidance on accounting for investments by a reporting entity in flow-through limited liability entities that manage or invest in affordable housing projects that qualify for the low-income housing tax credit. The amendments in this ASU modify the conditions that a reporting entity must meet to be eligible to use a method other than the equity or cost methods to account for qualified affordable housing project investments. If the modified conditions are met, the amendments permit an entity to amortize the initial cost of the investment in proportion to the amount of tax credits and other tax benefits received and recognize the net investment performance in the income statement as a component of income tax expense (benefit). Additionally, the amendments introduce new recurring disclosures about all investments in qualified affordable housing projects irrespective of the method used to account for the investments. The amendments in this ASU should be applied retrospectively to all periods presented. ASU No. 2014-01 is effective beginning after December 15, 2014 and is not expected to have a material impact on the Company's consolidated financial statements.
	Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure
	In January 2014, FASB issued ASU No. 2014-04, Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure. The amendments in this ASU clarify that an in-substance repossession or foreclosure occurs, and a creditor is considered to have received physical possession of residential real estate property collateralizing a consumer mortgage loan, upon either (1) the creditor obtaining legal title to the residential real estate property upon completion of a foreclosure or (2) the borrower conveying all interest in the residential real estate property to the creditor to satisfy that loan through completion of a deed in lieu of foreclosure or through a similar legal agreement. Additionally, the amendments require interim and annual disclosure of both (1) the amount of foreclosed residential real estate property held by the creditor and (2) the recorded investment in consumer mortgage loans collateralized by residential real estate property that are in the process of foreclosure according to local requirements of the applicable jurisdiction. ASU No. 2014-04 is effective for fiscal years and interim periods beginning after December 15, 2014 and is not expected to have a material impact on the Company's consolidated financial statements.
	Revenue from Contracts with Customers
	In May 2014, FASB issued ASU No. 2014-09, Revenue from Contracts with Customers, which creates Topic 606 and supersedes Topic 605, Revenue Recognition. The core principle of Topic 606 is that an entity recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In general, the new guidance requires companies to use more judgment and make more estimates than under current guidance, including identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. The standard is effective for public entities for interim and annual periods beginning after December 15, 2016; early adoption is not permitted. For financial reporting purposes, the standard allows for either full retrospective adoption, meaning the standard is applied to all of the periods presented, or modified retrospective adoption, meaning the standard is applied only to the most current period presented in the financial statements with the cumulative effect of initially applying the standard recognized at the date of initial application. The Company is currently evaluating the provisions of ASU No. 2014-09 to determine the potential impact the standard will have on the Company’s consolidated financial statements.
	Repurchase-to-Maturity Transactions, Repurchase Financings, and Disclosures
	In June 2014, FASB issued ASU No. 2014-11, Repurchase-to-Maturity Transactions, Repurchase Financings, and Disclosures, which requires the Company to consider these transactions as secured borrowings. The ASU seeks to prevent activities used leading up to the financial crisis regarding repurchase agreements, whereby pledges to maturity were recorded as sales, which may have over-reported income and may have under-reported liabilities, making it difficult for stakeholders to understand how a company was performing. The accounting changes in this ASU are effective for public business entities for the first interim or annual period beginning after December 15, 2014. Earlier application for a public business entity is prohibited. The accounting changes in this ASU are not expected to have a material impact on the Company's consolidated financial statements.
	Classification of Certain Government-Guaranteed Mortgage Loans upon Foreclosure
	In August 2014, FASB issued ASU No. 2014-14, Classification of Certain Government-Guaranteed Mortgage Loans upon Foreclosure. The amendments in this ASU affect creditors that hold government-guaranteed mortgage loans, including those guaranteed by the FHA and the VA. The ASU provides specific guidance on how to classify or measure foreclosed mortgage loans that are government guaranteed. The amendments in this ASU require that a mortgage loan be derecognized and that a separate other receivable be recognized upon foreclosure if the following conditions are met: 1) the loan has a government guarantee that is not separable from the loan before foreclosure, 2) at the time of foreclosure, the creditor has the intent to convey the real estate property to the guarantor and make a claim on the guarantee, and creditor has the ability to recover under the claim and, 3) at the time of foreclosure, any amount of the claim that is determined on the basis of the fair value of the real estate is fixed. ASU No. 2014-14 is effective for fiscal years and interim periods beginning after December 15, 2015 and is not expected to have a material impact on the Company's consolidated financial statements.
	Income Statement—Extraordinary and Unusual Items (Subtopic 225-20)
	In January 2015, FASB issued ASU No. 2015-01, Income Statement—Extraordinary and Unusual Items (Subtopic 225-20). The ASU eliminates from GAAP the concept of extraordinary items. Under subtopic 225-20, entities were required to separately classify, present, and disclose extraordinary events and transactions that were both unusual in nature and infrequent in occurrence. This amendment will save time and reduce costs for preparers, as well as alleviate uncertainty for auditors and regulators in evaluating potentially extraordinary items. The amendment is effective for fiscal years and interim reporting periods after December 15, 2015. It may be applied prospectively, and retrospectively to all reporting periods presented in the financial statements. The adoption of ASU No. 2015-01 is not expected to have a material impact on the Company's consolidated financial statements.

BUSINESS_COMBINATIONS_BUSINESS

BUSINESS COMBINATIONS BUSINESS COMBINATIONS	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
BUSINESS COMBINATIONS	BUSINESS COMBINATIONS
	Acquisition of Siuslaw Financial Group, Inc.
	Effective as of the close of business on March 6, 2015, the Company completed the purchase of Siuslaw Financial Group, Inc. (Siuslaw), the holding company of Siuslaw Bank, an Oregon state chartered commercial bank. The results of Siuslaw's operations will be included in the Company's operating results beginning March 7, 2015 and the combined company's banking operations will operate under the Banner Bank name and brand. As of March 6, 2015, Siuslaw had $370 million in total assets, $252 million in loans, and $318 million in deposits.
	The structure of the transaction is as follows:
	•	Siuslaw merged with and into the Company and, immediately following, Siuslaw Bank merged with and into Banner Bank;
	•	Siuslaw shareholders received 0.32231 shares of the Company's common stock and $1.41622 in cash in exchange for each share of Siuslaw common stock.
	Aggregate consideration for the purchase is estimated at $63.9 million and includes the following:
	•	Cash of $5.8 million;
	•	Common stock issued of $58.1 million.
	The primary reason for the acquisition is to continue the Company's growth strategy, including expanding our geographic footprint in markets throughout the Northwest. The assets acquired and liabilities assumed in the purchase will be accounted for under the acquisition method of accounting and, accordingly, the assets and liabilities, both tangible and intangible will be recorded at fair value as of the acquisition date. Preliminary fair values for all assets and liabilities are not reported herein as the Company is still in the process of determining the preliminary fair values. The Company expects to disclose preliminary assets acquired and liabilities assumed, including fair value adjustments, as well as supplemental pro forma information, in the Company's March 31, 2015 Form 10-Q. Goodwill will not be deductible for income tax purposes as the acquisition is accounted for as a tax-free exchange for tax purposes.
	Acquisition of Six Oregon Branches
	Effective as of the close of business on June 20, 2014, Banner Bank completed the purchase of six branches from Umpqua Bank, successor to Sterling Savings Bank (the Branch Acquisition). Five of the six branches are located in Coos County, Oregon and the sixth branch is located in Douglas County, Oregon. The purchase provided $212 million in deposit accounts, $88 million in loans, and $3 million in branch properties. Banner Bank received $128 million in cash from the transaction.
	The assets acquired and liabilities assumed in the purchase have been accounted for under the acquisition method of accounting. The assets and liabilities, both tangible and intangible, were recorded at their estimated fair values as of the acquisition date. The application of the acquisition method of accounting resulted in recognition of a core deposit intangible asset of $2.4 million and an acquisition bargain purchase gain of $9.1 million. The bargain purchase gain represents the excess fair value of the net assets acquired over the purchase price, including fair value of liabilities assumed. The bargain purchase gain consisted primarily of a $7.0 million discount on the assets acquired in this required branch divestiture combined with a $2.4 million core deposit intangible, net of approximately $300,000 in other fair value adjustments. The acquired core deposit intangible has been determined to have a useful life of approximately eight years and will be amortized on an accelerated basis.
	The following table displays the fair value as of the acquisition date for each major class of assets acquired and liabilities assumed (in thousands):
		Fair Value at Acquisition
		20-Jun-14
	Assets:
	Cash	$	127,557
	Loans receivable (contractual amount of $88.3 million)	87,923
	Property and equipment	3,079
	Core deposit intangible	2,372
	Other assets	275
	Total assets	221,206
	Liabilities:
	Deposits	212,085
	Other liabilities	42
	Total liabilities	212,127
	Acquisition bargain purchase gain	$	9,079
	The primary reason for the acquisition was to continue the Company's growth strategy, including expanding our geographic footprint in markets throughout the Northwest. As of June 20, 2014, the transaction had no remaining contingencies. The operating results of the Company include the operating results produced by the six acquired branches from June 21, 2014 to December 31, 2014. Pro forma results of operations for the years ended December 31, 2014 and 2013 , as if the Branch Acquisition had occurred on January 1, 2013, have not been presented because historical financial information was not available.
	Acquisition Related Costs
	The following table presents the key components of acquisition related costs in connection with the Branch Acquisition, the acquisition of Siuslaw, and the proposed acquisition of AmericanWest for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Years Ended December 31
		2014		2013		2012
	Acquisition-related costs recognized in other operating expenses:
	Non-capitalized equipment and repairs	$	105	$	—	$	—
	Client communications	327		—		—
	Information/computer data services	334		—		—
	Payment and processing expenses	185		—		—
	Professional services	2,953		550		—
	Miscellaneous	421		—		—
		$	4,325	$	550	$	—

CASH_AND_SECURITIES

CASH AND SECURITIES	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
CASH AND SECURITIES	CASH AND SECURITIES
	Cash, due from bank and cash equivalents consisted of the following at the dates indicated (in thousands):
		31-Dec
		2014		2013
	Cash on hand and due from banks	$	125,689	$	136,810
	Cash equivalents:
	Short-term cash investments	383		539
		$	126,072	$	137,349
	Federal regulations require depository institutions to maintain certain minimum reserve balances.  Included in cash and demand deposits were required reserves of $33.0 million and $30.0 million at December 31, 2014 and 2013, respectively.
	The following table sets forth a summary of Banner’s interest-bearing deposits and securities at the dates indicated (includes securities—trading, available-for-sale and held-to-maturity, all at carrying value) (in thousands):
		31-Dec
		2014		2013
	Interest-bearing deposits included in cash and due from banks	$	54,995	$	67,638
	U.S. Government and agency obligations	33,421		61,327
	Municipal bonds:
	Taxable	29,566		34,216
	Tax exempt	141,853		119,588
	Total municipal bonds	171,419		153,804
	Corporate bonds	25,936		44,154
	Mortgage-backed or related securities:
	One- to four-family residential agency guaranteed	58,825		58,117
	One- to four-family residential other	713		1,051
	Multifamily agency guaranteed	256,272		281,319
	Multifamily other	10,497		10,234
	Total mortgage-backed securities	326,307		350,721
	Asset-backed securities:
	Student Loan Marketing Association (SLMA)	15,629		15,681
	Other asset-backed securities	9,766		9,510
	Total asset-backed securities	25,395		25,191
	Equity securities (excludes FHLB stock)	59		68
	Total securities	582,537		635,265
	FHLB stock	27,036		35,390
		$	664,568	$	738,293
	Securities—Trading:  The amortized cost and estimated fair value of securities—trading at December 31, 2014 and 2013 are summarized as follows (dollars in thousands):
		December 31, 2014								December 31, 2013
		Amortized		Fair Value			Percent of			Amortized				Fair Value			Percent of
		Cost					Total			Cost							Total
	U.S. Government and agency obligations	$	1,340	$	1,505		3.7	%		$	1,370			$	1,481		2.4	%
	Municipal bonds:
	Tax exempt	1,405		1,440			3.6			4,969				5,023			8
	Corporate bonds	27,995		19,118			47.5			49,498				35,140			56.2
	Mortgage-backed or related securities:
	One- to four-family residential agency guaranteed	8,077		8,726			21.7			10,483				11,230			18
	Multifamily agency guaranteed	8,649		9,410			23.4			8,816				9,530			15.3
	Total mortgage-backed or related securities	16,726		18,136			45.1			19,299				20,760			33.3
	Equity securities	14		59			0.1			14				68			0.1
		$	47,480	$	40,258		100	%		$	75,150			$	62,472		100	%
	There were three sales of securities—trading totaling $2.4 million with a resulting net gain of $1,000 for the year ended December 31, 2014. There were 44 sales of securities—trading totaling $34.3 million with a resulting net gain of $1.5 million for the year ended December 31, 2013, including $1.0 million which represented recoveries on certain collateralized debt obligations that had previously been written off. In addition to the $1.5 million net gain, the Company also recognized a $409,000 OTTI recovery on sales of securities—trading for the year ended December 31, 2013, which was related to the sale of certain equity securities issued by government-sponsored entities. There were eight sales of securities—trading totaling $5.1 million with a resulting net gain of $13,000 for the year ended December 31, 2012. The Company did not recognize any OTTI charges or recoveries on securities—trading during the year ended December 31, 2014. The $409,000 OTTI recovery in 2013 reversed a $409,000 OTTI charge during the year ended December 31, 2012 related to the same equity securities. There were no securities—trading in a nonaccrual status at December 31, 2014 and 2013.  Net unrealized holding gains of $5.5 million were recognized in 2014.
	The amortized cost and estimated fair value of securities—trading at December 31, 2014 and 2013, by contractual maturity, are shown below (in thousands).  Expected maturities will differ from contractual maturities because some securities may be called or prepaid with or without call or prepayment penalties.
		December 31, 2014					December 31, 2013
		Amortized Cost		Fair Value			Amortized Cost				Fair Value
	Maturing in one year or less	$	1,071	$	1,094		$	260			$	263
	Maturing after one year through five years	6,595		7,097			7,056				7,298
	Maturing after five years through ten years	7,035		7,727			12,602				13,572
	Maturing after ten years through twenty years	11,196		10,083			33,335				27,472
	Maturing after twenty years	21,569		14,198			21,883				13,799
		47,466		40,199			75,136				62,404
	Equity securities	14		59			14				68
		$	47,480	$	40,258		$	75,150			$	62,472
	Securities—Available-for-Sale:  The amortized cost, gross unrealized losses and gains and estimated fair value of securities— available-for-sale at December 31, 2014 and 2013 are summarized as follows (dollars in thousands):
		December 31, 2014
		Amortized Cost		Gross Unrealized Gains			Gross Unrealized Losses				Fair Value				Percent of Total
	U.S. Government and agency obligations	$	29,973	$	8		$	(211	)		$	29,770			7.2	%
	Municipal bonds:
Taxable	16,565		65			(52		)		16,578				4
Tax exempt	33,394		125			(69		)		33,450				8.2
Total municipal bonds	49,959		190			(121		)		50,028				12.2
Corporate bonds	5,000		18			—				5,018				1.2
Mortgage-backed or related securities:
One- to four-family residential agency guaranteed	48,001		758			(240		)		48,519				11.8
One- to four-family residential other	675		38			—				713				0.2
Multifamily agency guaranteed	241,800		627			(1,346		)		241,081				58.7
Multifamily other	10,503		6			(12		)		10,497				2.5
Total mortgage-backed or related securities	300,979		1,429			(1,598		)		300,810				73.2
Asset-backed securities:
SLMA	15,462		167			—				15,629				3.8
Other asset-backed securities	10,051		—			(285		)		9,766				2.4
Total asset-backed securities	25,513		167			(285		)		25,395				6.2
	$	411,424	$	1,812		$	(2,215	)		$	411,021			100	%
	December 31, 2013
	Amortized Cost		Gross Unrealized Gains			Gross Unrealized Losses				Fair Value				Percent of Total
U.S. Government and agency obligations	$	59,178	$	117		$	(635	)		$	58,660			12.5	%
Municipal bonds:
Taxable	23,842		100			(278		)		23,664				5
Tax exempt	29,229		170			(208		)		29,191				6.2
Total municipal bonds	53,071		270			(486		)		52,855				11.2
Corporate bonds	7,001		2			(39		)		6,964				1.5
Mortgage-backed or related securities:
One- to four-family residential agency guaranteed	47,077		648			(838		)		46,887				10
One- to four-family residential other	988		63			—				1,051				0.2
Multifamily agency guaranteed	271,428		402			(3,392		)		268,438				57.1
Multifamily other	10,604		—			(370		)		10,234				2.2
Total mortgage-backed or related securities	330,097		1,113			(4,600		)		326,610				69.5
Asset-backed securities:
SLMA	15,553		128			—				15,681				3.3
Other asset-backed securities	10,060		—			(550		)		9,510				2
Total asset-backed securities	25,613		128			(550		)		25,191				5.3
	$	474,960	$	1,630		$	(6,310	)		$	470,280			100	%
At December 31, 2014 and 2013, an aging of unrealized losses and fair value of related securities—available-for-sale was as follows (in thousands):
	December 31, 2014
	Less Than 12 Months					12 Months or More								Total
	Fair Value		Unrealized			Fair Value				Unrealized				Fair Value			Unrealized
			Losses							Losses							Losses
U.S. Government and agency obligations	$	15,983	$	(58	)	$	9,847			$	(153	)		$	25,830		$	(211	)
Municipal bonds:
Taxable	7,247		(23		)	3,461				(29		)		10,708			(52		)
Tax exempt	9,075		(38		)	3,668				(31		)		12,743			(69		)
Total municipal bonds	16,322		(61		)	7,129				(60		)		23,451			(121		)
Mortgage-backed or related securities:
One- to four-family residential agency guaranteed	6,287		(57		)	11,744				(183		)		18,031			(240		)
Multifamily agency guaranteed	76,309		(167		)	95,522				(1,179		)		171,831			(1,346		)
Multifamily other	8,450		(12		)	—				—				8,450			(12		)
Total mortgage-backed or related securities	91,046		(236		)	107,266				(1,362		)		198,312			(1,598		)
Asset-backed securities:
Other asset-backed securities	—		—			9,765				(285		)		9,765			(285		)
	$	123,351	$	(355	)	$	134,007			$	(1,860	)		$	257,358		$	(2,215	)
	December 31, 2013
	Less Than 12 Months					12 Months or More								Total
	Fair Value		Unrealized			Fair Value				Unrealized				Fair Value			Unrealized
			Losses							Losses							Losses
U.S. Government and agency obligations	$	39,621	$	(633	)	$	998			$	(2	)		$	40,619		$	(635	)
Municipal bonds:
Taxable	15,580		(261		)	413				(17		)		15,993			(278		)
Tax exempt	8,217		(205		)	487				(3		)		8,704			(208		)
Total municipal bonds	23,797		(466		)	900				(20		)		24,697			(486		)
Corporate bonds	4,961		(39		)	—				—				4,961			(39		)
Mortgage-backed or related securities:
One- to four-family residential agency guaranteed	14,972		(133		)	22,560				(705		)		37,532			(838		)
Multifamily agency guaranteed	199,407		(3,162		)	10,096				(230		)		209,503			(3,392		)
Multifamily other	10,234		(370		)	—				—				10,234			(370		)
Total mortgage-backed or related securities	224,613		(3,665		)	32,656				(935		)		257,269			(4,600		)
Asset-backed securities:
Other asset-backed securities	—		—			9,510				(550		)		9,510			(550		)
	$	292,992	$	(4,803	)	$	44,064			$	(1,507	)		$	337,056		$	(6,310	)
There were 13 sales of securities—available-for-sale totaling $56.3 million with a resulting net gain of $41,000 for the year ended December 31, 2014.  There were 35 sales of securities—available-for-sale totaling $103.3 million with a resulting net loss of $116,000 for the year ended December 31, 2013. There were three sales of securities—available-for-sale totaling $13.3 million with a resulting net gain of $38,000 for the year ended December 31, 2012.  At December 31, 2014, there were 94 securities—available-for-sale with unrealized losses, compared to 114 at December 31, 2013 and 52 at December 31, 2012.  Management does not believe that any individual unrealized loss as of December 31, 2014, 2013 or 2012 represented OTTI.  The decline in fair market value of these securities was generally due to changes in interest rates and changes in market-desired spreads subsequent to their purchase. There were no securities—available-for-sale in a nonaccrual status at December 31, 2014 and 2013.
The amortized cost and estimated fair value of securities—available-for-sale at December 31, 2014 and 2013, by contractual maturity, are shown below (in thousands).  Expected maturities will differ from contractual maturities because some securities may be called or prepaid with or without call or prepayment penalties.
	December 31, 2014					December 31, 2013
	Amortized Cost		Fair Value			Amortized Cost				Fair Value
Maturing in one year or less	$	9,334	$	9,364		$	25,136			$	25,256
Maturing after one year through five years	278,629		277,439			322,493				319,489
Maturing after five years through ten years	45,425		45,610			58,468				57,782
Maturing after ten years through twenty years	13,846		13,879			15,535				15,135
Maturing after twenty years	64,190		64,729			53,328				52,618
	$	411,424	$	411,021		$	474,960			$	470,280
Securities—Held-to-Maturity:  The amortized cost, gross gains and losses and estimated fair value of securities—held-to-maturity at December 31, 2014 and 2013 are summarized as follows (dollars in thousands):
	December 31, 2014
	Amortized Cost		Gross Unrealized Gains			Gross Unrealized Losses				Fair Value				Percent of Total Amortized Cost
U.S. Government and agency obligations	$	2,146	$	—		$	(19	)		$	2,127			1.6	%
Municipal bonds:
Taxable	12,988		371			(1		)		13,358				9.9
Tax exempt	106,963		5,948			(47		)		112,864				81.5
Total municipal bonds	119,951		6,319			(48		)		126,222				91.4
Corporate bonds	1,800		—			—				1,800				1.4
Mortgage-backed or related securities:
One- to four-family residential agency guaranteed	1,580		1			(7		)		1,574				1.2
Multifamily agency guaranteed	5,781		104			—				5,885				4.4
Total mortgage-backed or related securities	7,361		105			(7		)		7,459				5.6
	$	131,258	$	6,424		$	(74	)		$	137,608			100	%
	December 31, 2013
	Amortized Cost		Gross Unrealized Gains			Gross Unrealized Losses				Fair Value				Percent of Total Amortized Cost
U.S. Government and agency obligations	$	1,186	$	—		$	(80	)		$	1,106			1.1	%
Municipal bonds:
Taxable	10,552		193			(204		)		10,541				10.3
Tax exempt	85,374		2,545			(1,299		)		86,620				83.3
Total municipal bonds	95,926		2,738			(1,503		)		97,161				93.6
Corporate bonds	2,050		—			—				2,050				2
Mortgage-backed or related securities:
Multifamily agency guaranteed	3,351		—			(58		)		3,293				3.3
	$	102,513	$	2,738		$	(1,641	)		$	103,610			100	%
At December 31, 2014 and 2013, an age analysis of unrealized losses and fair value of related securities—held-to-maturity was as follows (in thousands):
	December 31, 2014
	Less Than 12 Months					12 Months or More								Total
	Fair Value		Unrealized			Fair Value				Unrealized				Fair Value			Unrealized
			Losses							Losses							Losses
U.S. Government and agency obligations	$	—	$	—		$	1,127			$	(19	)		$	1,127		$	(19	)
Municipal bonds:
Taxable	724		(1		)	—				—				724			(1		)
Tax exempt	9,097		(43		)	592				(4		)		9,689			(47		)
Total municipal bonds	9,821		(44		)	592				(4		)		10,413			(48		)
Mortgage-backed or related securities:
One- to four-family residential agency guaranteed	1,018		(7		)	—				—				1,018			(7		)
	$	10,839	$	(51	)	$	1,719			$	(23	)		$	12,558		$	(74	)
	December 31, 2013
	Less Than 12 Months					12 Months or More								Total
	Fair Value		Unrealized			Fair Value				Unrealized				Fair Value			Unrealized
			Losses							Losses							Losses
U.S. Government and agency obligations	$	1,106	$	(80	)	$	—			$	—			$	1,106		$	(80	)
Municipal bonds:
Taxable	3,344		(110		)	2,964				(94		)		6,308			(204		)
Tax exempt	31,234		(1,282		)	303				(17		)		31,537			(1,299		)
Total municipal bonds	34,578		(1,392		)	3,267				(111		)		37,845			(1,503		)
Mortgage-backed or related securities:
Multifamily agency guaranteed	3,293		(58		)	—				—				3,293			(58		)
	$	38,977	$	(1,530	)	$	3,267			$	(111	)		$	42,244		$	(1,641	)
There were no sales of securities—held-to-maturity during the years ended December 31, 2014, 2013 or 2012. At December 31, 2014, there were 25 securities—held-to-maturity with unrealized losses, compared to 36 at December 31, 2013 and five at December 31, 2012.  Management does not believe that any individual unrealized losses as of December 31, 2014 or 2013 represented OTTI.  The decline in fair market value of these securities was generally due to changes in interest rates and changes in market-desired spreads subsequent to their purchase. There were no securities—held-to-maturity in a nonaccrual status at December 31, 2014 and 2013.
The amortized cost and estimated fair value of securities—held-to-maturity at December 31, 2014 and 2013, by contractual maturity, are shown below (in thousands).  Expected maturities will differ from contractual maturities because some securities may be called or prepaid with or without call or prepayment penalties.
	December 31, 2014					December 31, 2013
	Amortized Cost		Fair Value			Amortized Cost				Fair Value
Maturing in one year or less	$	767	$	771		$	1,270			$	1,281
Maturing after one year through five years	14,962		15,184			10,834				11,206
Maturing after five years through ten years	24,233		24,678			17,948				17,908
Maturing after ten years through twenty years	76,029		81,361			59,643				60,791
Maturing after twenty years	15,267		15,614			12,818				12,424
	$	131,258	$	137,608		$	102,513			$	103,610
Pledged Securities: The following table presents, as of December 31, 2014, investment securities which were pledged to secure borrowings, public deposits or other obligations as permitted or required by law (in thousands):
	Carrying Value		Amortized Cost			Fair Value
Purpose or beneficiary:
State and local governments public deposits	$	116,273	$	116,242		$	122,130
Interest rate swap counterparties	11,051		10,648			11,051
Retail repurchase transaction accounts	98,735		98,435			98,735
Other	248		248			248
Total pledged securities	$	226,307	$	225,573		$	232,164
Interest Income from Securities and Cash Equivalents: The following table sets forth the composition of interest income from securities and cash equivalents for the periods indicated (in thousands):
	Years Ended December 31
	2014		2013			2012
Mortgage-backed securities interest	$	5,779	$	5,168		$	4,176
Other taxable interest income	3,101		3,601			5,087
Tax-exempt interest income	4,206		3,721			3,577
FHLB stock—dividend income	34		18			—
Total interest income from securities and cash equivalents	$	13,120	$	12,508		$	12,840

LOANS_RECEIVABLE_AND_THE_ALLOW

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES	12 Months Ended
	Dec. 31, 2014
Receivables [Abstract]
LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES	LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES
	Loans receivable, including loans held for sale, at December 31, 2014 and 2013 are summarized as follows (dollars in thousands):
		December 31, 2014							December 31, 2013
		Amount				Percent of Total			Amount				Percent of Total
	Commercial real estate:
	Owner-occupied	$	546,783			14.3	%		$	502,601			14.7	%
	Investment properties	856,942				22.3			692,457				20.2
	Multifamily real estate	167,524				4.4			137,153				4
	Commercial construction	17,337				0.4			12,168				0.4
	Multifamily construction	60,193				1.6			52,081				1.5
	One- to four-family construction	219,889				5.7			200,864				5.9
	Land and land development:
	Residential	102,435				2.7			75,695				2.2
	Commercial	11,152				0.3			10,450				0.3
	Commercial business	723,964				18.9			682,169				20
	Agricultural business, including secured by farmland	238,499				6.2			228,291				6.7
	One- to four-family residential	539,894				14.1			529,494				15.5
	Consumer:
	Consumer secured by one- to four-family	222,205				5.8			173,188				5.1
	Consumer—other	127,003				3.3			121,834				3.5
	Total loans outstanding	3,833,820				100	%		3,418,445				100	%
	Less allowance for loan losses	(75,907		)					(74,258		)
	Net loans	$	3,757,913						$	3,344,187
	Loan amounts are net of unearned, unamortized loan fees (and costs) of approximately $5.8 million at December 31, 2014 and approximately $8.3 million at December 31, 2013.
	The Company’s loans by geographic concentration at December 31, 2014 were as follows (dollars in thousands):
		Washington				Oregon				Idaho				Other			Total
	Commercial real estate:
	Owner-occupied	$	383,950			$	86,937			$	56,348			$	19,548		$	546,783
	Investment properties	523,806				124,604				60,053				148,479			856,942
	Multifamily real estate	116,793				35,527				14,759				445			167,524
	Commercial construction	15,599				—				1,738				—			17,337
	Multifamily construction	50,931				8,850				412				—			60,193
	One- to four-family construction	129,499				88,468				1,922				—			219,889
	Land and land development:
	Residential	56,675				44,707				1,053				—			102,435
	Commercial	5,781				2,529				2,842				—			11,152
	Commercial business	397,103				125,235				85,580				116,046			723,964
	Agricultural business, including secured by farmland	119,617				69,843				48,997				42			238,499
	One- to four-family residential	341,944				172,974				24,223				753			539,894
	Consumer:
	Consumer secured by one- to four-family	136,888				69,172				14,984				1,161			222,205
	Consumer—other	79,520				40,803				6,243				437			127,003
	Total loans	$	2,358,106			$	869,649			$	319,154			$	286,911		$	3,833,820
	Percent of total loans	61.5		%		22.7		%		8.3		%		7.5		%	100		%
	The geographic concentrations of land and land development loans by state at December 31, 2014 were as follows (dollars in thousands):
		Washington				Oregon				Idaho				Total
	Residential:
	Acquisition and development	$	28,901			$	24,378			$	916			$	54,195
	Improved land and lots	21,703				17,262				137				39,102
	Unimproved land	6,071				3,067				—				9,138
	Commercial and industrial:
	Improved land and lots	3,750				478				1,783				6,011
	Unimproved land	2,031				2,051				1,059				5,141
	Total land and land development loans	$	62,456			$	47,236			$	3,895			$	113,587
	Percent of land and land development loans	55		%		41.6		%		3.4		%		100		%
	The Company originates both adjustable- and fixed-rate loans.  At December 31, 2014 and 2013, the maturity and repricing composition of those loans, less undisbursed amounts and deferred fees and origination costs, were as follows (in thousands):
		31-Dec
		2014				2013
	Fixed-rate (term to maturity):
	Maturing in one year or less	$	115,571			$	122,313
	Maturing after one year through three years	184,707				143,322
	Maturing after three years through five years	180,449				187,279
	Maturing after five years through ten years	240,742				209,869
	Maturing after ten years	572,793				439,004
Total fixed-rate loans	1,294,262				1,101,787
Adjustable-rate (term to rate adjustment):
Maturing or repricing in one year or less	1,468,316				1,390,579
Maturing or repricing after one year through three years	416,433				279,791
Maturing or repricing after three years through five years	566,371				541,529
Maturing or repricing after five years through ten years	87,506				99,503
Maturing or repricing after ten years	932				5,256
Total adjustable-rate loans	2,539,558				2,316,658
Total loans	$	3,833,820			$	3,418,445
The adjustable-rate loans have interest rate adjustment limitations and are generally indexed to various prime or LIBOR rates, FHLB advance rates or One- to Five-Year Constant Maturity Treasury Indices.  Future market factors may affect the correlation of the interest rate adjustment with the rates the Banks pay on the short-term deposits that primarily have been utilized to fund these loans.
The Company’s loans to directors, executive officers and related entities are on substantially the same terms and underwriting as those prevailing at the time for comparable transactions with unrelated persons and do not involve more than normal risk of collectability.  Such loans had the following balances and activity during the years ended December 31, 2014 and 2013 (in thousands):
	Years Ended December 31
	2014				2013
Balance at beginning of year	$	15,976			$	12,463
New loans or advances	38,241				39,921
Repayments and adjustments	(45,608		)		(36,408		)
Balance at end of period	$	8,609			$	15,976
Impaired Loans and the Allowance for Loan Losses:  A loan is considered impaired when, based on current information and circumstances, the Company determines it is probable that it will be unable to collect all amounts due according to the contractual terms of the loan agreement, including scheduled interest payments.  Impaired loans are comprised of loans on nonaccrual, TDRs that are performing under their restructured terms, and loans that are 90 days or more past due, but are still on accrual.
The amount of impaired loans and the related allocated reserve for loan losses at the dates indicated were as follows (in thousands):
	December 31, 2014								December 31, 2013
	Loan Amount				Allocated				Loan Amount				Allocated
					Reserves								Reserves
Impaired loans:
Nonaccrual loans
Commercial real estate:
Owner-occupied	$	1,365			$	20			$	2,466			$	31
Investment properties	32				5				3,821				89
One- to four-family construction	—				—				269				—
Land and land development:
Residential	1,275				—				924				6
Commercial business	537				46				724				104
Agricultural business, including secured by farmland	1,597				26				—				—
One- to four-family residential	8,507				35				12,532				250
Consumer:
Consumer secured by one- to four-family	838				47				903				13
Consumer—other	411				—				269				1
Total nonaccrual loans	14,562				179				21,908				494
Loans 90 days past due and still accruing
Agricultural business, including secured by farmland	—				—				105				8
One- to four-family residential	2,095				10				2,611				16
Consumer:
Consumer secured by one- to four-family	80				—				13				—
Consumer—other	—				—				131				1
Total loans 90 days past due and still accruing	2,175				10				2,860				25
Troubled debt restructuring on accrual status:
Commercial real estate:
Owner-occupied	184				4				186				4
Investment properties	6,021				724				5,367				415
Multifamily real estate	786				86				5,744				1,139
One- to four-family construction	3,923				640				6,864				1,002
Land and land development:
Residential	1,279				346				4,061				754
Commercial business	739				82				1,299				222
One- to four-family residential	15,792				987				23,302				1,355
Consumer:
Consumer secured by one- to four-family	233				28				360				33
Consumer—other	197				6				245				34
Total troubled debt restructurings on accrual status	29,154				2,903				47,428				4,958
Total impaired loans	$	45,891			$	3,092			$	72,196			$	5,477
As of December 31, 2014 and 2013, the Company had commitments to advance funds up to an additional amount of $2.1 million and $225,000, respectively, related to TDRs.
The following tables provide additional information on impaired loans with and without specific allowance reserves as of December 31, 2014 and December 31, 2013.  Recorded investment includes the unpaid principal balance or the carrying amount of loans less charge-offs and net deferred loan fees (in thousands):
	At or For the Year Ended December 31, 2014
	Recorded Investment				Unpaid				Related				Average			Interest
					Principal				Allowance				Recorded Investment			Income
					Balance											Recognized
Without a specific allowance reserve (1)
Commercial real estate:
Owner-occupied	$	399			$	449			$	20			$	526		$	—
Investment properties	32				32				5				44			—
Commercial business	537				763				46				566			—
Agricultural business, including secured by farmland	853				853				26				1,122			—
One- to four-family residential	8,546				9,244				18				7,284			29
Consumer:
Consumer secured by one- to four-family	783				888				11				838			3
Consumer—other	295				305				—				270			—
	11,445				12,534				126				10,650			32
With a specific allowance reserve (2)
Commercial real estate:
Owner-occupied	1,149				1,149				4				1,315			12
Investment properties	6,022				6,426				724				6,101			315
Multifamily real estate	786				786				86				795			45
One- to four-family construction	3,923				3,923				640				2,655			118
Land and land development:
Residential	2,554				3,710				346				2,872			89
Commercial business	739				739				82				762			41
Agricultural business, including secured by farmland	744				744				—				744			—
One- to four-family residential	17,848				18,611				1,014				18,809			841
Consumer:
Consumer secured by one- to four-family	368				368				64				410			16
Consumer—other	313				329				6				327			19
	34,446				36,785				2,966				34,790			1,496
Total
Commercial real estate:
Owner occupied	1,548				1,598				24				1,841			12
Investment properties	6,054				6,458				729				6,145			315
Multifamily real estate	786				786				86				795			45
One- to four-family construction	3,923				3,923				640				2,655			118
Land and land development:
Residential	2,554				3,710				346				2,872			89
Commercial business	1,276				1,502				128				1,328			41
Agricultural business, including secured by farmland	1,597				1,597				26				1,866			—
One- to four-family residential	26,394				27,855				1,032				26,093			870
Consumer:
Consumer secured by one- to four-family	1,151				1,256				75				1,248			19
Consumer—other	608				634				6				597			19
	$	45,891			$	49,319			$	3,092			$	45,440		$	1,528
	At or For the Year Ended December 31, 2013
	Recorded Investment				Unpaid				Related				Average			Interest
					Principal				Allowance				Recorded Investment			Income
					Balance											Recognized
Without a specific allowance reserve (1)
Commercial real estate:
Owner-occupied	$	534			$	584			$	31			$	569		$	—
Investment properties	429				974				89				624			—
Commercial business	724				1,040				104				896			—
Agricultural business, including secured by farmland	105				105				8				110			8
One- to four-family residential	8,611				9,229				42				8,889			31
Consumer:
Consumer secured by one- to four-family	870				1,013				13				900			1
Consumer—other	276				285				2				287			8
	11,549				13,230				289				12,275			48
With a specific allowance reserve (2)
Commercial real estate:
Owner-occupied	2,118				2,118				4				2,192			12
Investment properties	8,759				10,395				415				8,353			241
Multifamily real estate	5,744				5,744				1,139				5,705			298
One- to four-family construction	7,133				7,213				1,002				5,870			239
Land and land development:
Residential	4,985				6,140				760				6,053			221
Commercial business	1,298				1,298				222				1,340			59
One- to four-family residential	29,834				31,440				1,579				31,668			1,032
Consumer:
Consumer secured by one- to four-family	406				407				33				503			24
Consumer—other	370				386				34				390			21
	60,647				65,141				5,188				62,074			2,147
Total
Commercial real estate:
Owner-occupied	2,652				2,702				35				2,761			12
Investment properties	9,188				11,369				504				8,977			241
Multifamily real estate	5,744				5,744				1,139				5,705			298
One- to four-family construction	7,133				7,213				1,002				5,870			239
Land and land development:
Residential	4,985				6,140				760				6,053			221
Commercial business	2,022				2,338				326				2,236			59
Agricultural business, including secured by farmland	105				105				8				110			8
One- to four-family residential	38,445				40,669				1,621				40,557			1,063
Consumer:
Consumer secured by one- to four-family	1,276				1,420				46				1,403			25
Consumer—other	646				671				36				677			29
	$	72,196			$	78,371			$	5,477			$	74,349		$	2,195
(1)	Loans without a specific allowance reserve have not been individually evaluated for impairment, but have been included in pools of homogeneous loans for evaluation of related allowance reserves.
(2)	Loans with a specific allowance reserve have been individually evaluated for impairment using either a discounted cash flow analysis or, for collateral dependent loans, current appraisals to establish realizable value. These analyses may identify a specific impairment amount needed or may conclude that no reserve is needed. Any specific impairment that is identified is included in the category’s "Related Allowance" column.
The following tables present TDRs at December 31, 2014 and 2013 (in thousands):
	December 31, 2014
	Accrual				Nonaccrual				Total
	Status				Status				TDRs
Commercial real estate:
Owner-occupied	$	183			$	109			$	292
Investment properties	6,021				32				6,053
Multifamily real estate	786				—				786
One- to four-family construction	3,923				—				3,923
Land and land development:
Residential	1,279				525				1,804
Commercial business	739				87				826
One- to four-family residential	15,793				1,363				17,156
Consumer:
Consumer secured by one- to four-family	233				117				350
Consumer—other	197				116				313
	$	29,154			$	2,349			$	31,503
	December 31, 2013
	Accrual				Nonaccrual				Total
	Status				Status				TDRs
Commercial real estate:
Owner-occupied	$	186			$	613			$	799
Investment properties	5,367				1,630				6,997
Multifamily real estate	5,744				—				5,744
One- to four-family construction	6,864				269				7,133
Land and land development:
Residential	4,061				174				4,235
Commercial business	1,299				164				1,463
One- to four-family residential	23,302				2,474				25,776
Consumer:
Consumer secured by one- to four-family	360				252				612
Consumer—other	245				123				368
	$	47,428			$	5,699			$	53,127
The following tables present new TDRs that occurred during the years ended December 31, 2014 and 2013 (dollars in thousands):
	Year Ended December 31, 2014
	Number of			Pre-modification Outstanding Recorded Investment				Post-modification Outstanding Recorded Investment
	Contracts
Recorded Investment (1) (2)
Commercial real estate:
Owner-occupied	1			$	203			$	203
One- to four-family construction	10			2,153				2,153
Commercial business	1			100				100
One- to four-family residential	4			905				862
Consumer - other	1			9				9
	17			$	3,370			$	3,327
	Year Ended December 31, 2013
	Number of			Pre-modification Outstanding Recorded Investment				Post-modification Outstanding Recorded Investment
	Contracts
Recorded Investment (1) (2)
Commercial real estate:
Owner-occupied	1			$	1,246			$	1,246
Multifamily real estate	1			375				375
One- to four-family construction	8			3,082				3,082
Land and land development:
Residential	2			1,029				1,029
Commercial business	1			100				100
One- to four-family residential	10			2,726				2,726
	23			$	8,558			$	8,558
(1)	Since most loans were already considered classified and/or on non-accrual status prior to restructuring, the modifications did not have a material effect on the Company’s determination of the allowance for loan losses.
(2)	The majority of these modifications do not fit into one separate type, such as: rate, term, amount, interest-only or payment; but instead are a combination of multiple types of modifications, therefore they are disclosed in aggregate.
The following table presents TDRs which incurred a payment default within the years ended December 31, 2014 and 2013, for which the payment default occurred within twelve months of the restructure date.  A default on a restructured loan results in a transfer to nonaccrual status, a charge-off or a combination of both (in thousands):
	Years Ended December 31
	2014							2013
	Number of Loans			Amount				Number of Loans			Amount
Construction and land	—			$	—			2			$	483
Commercial business	—			—				2			321
One- to four-family residential	—			—				2			222
Total	—			$	—			6			$	1,026
Credit Quality Indicators:  To appropriately and effectively manage the ongoing credit quality of the Company’s loan portfolio, management has implemented a risk-rating or loan grading system for its loans.  The system is a tool to evaluate portfolio asset quality throughout each applicable loan’s life as an asset of the Company.  Generally, loans and leases are risk rated on an aggregate borrower/relationship basis with individual loans sharing similar ratings.  There are some instances when specific situations relating to individual loans will provide the basis for different risk ratings within the aggregate relationship.  Loans are graded on a scale of 1 to 9.  A description of the general characteristics of these categories is shown below:
Overall Risk Rating Definitions:  Risk-ratings contain both qualitative and quantitative measurements and take into account the financial strength of a borrower and the structure of the loan or lease.  Consequently, the definitions are to be applied in the context of each lending transaction and judgment must also be used to determine the appropriate risk rating, as it is not unusual for a loan or lease to exhibit characteristics of more than one risk-rating category.  Consideration for the final rating is centered in the borrower’s ability to repay, in a timely fashion, both principal and interest.  There were no material changes in the risk-rating or loan grading system in 2014.
Risk Rating 1: Exceptional
A credit supported by exceptional financial strength, stability, and liquidity.  The risk rating of 1 is reserved for the Company’s top quality loans, generally reserved for investment grade credits underwritten to the standards of institutional credit providers.
Risk Rating 2: Excellent
A credit supported by excellent financial strength, stability and liquidity.  The risk rating of 2 is reserved for very strong and highly stable customers with ready access to alternative financing sources.
Risk Rating 3: Strong
A credit supported by good overall financial strength and stability.  Collateral margins are strong, cash flow is stable although susceptible to cyclical market changes.
Risk Rating 4: Acceptable
A credit supported by the borrower’s adequate financial strength and stability.  Assets and cash flow are reasonably sound and provide for orderly debt reduction.  Access to alternative financing sources will be more difficult to obtain.
Risk Rating 5: Watch
A credit with the characteristics of an acceptable credit but one which requires more than the normal level of supervision and warrants formal quarterly management reporting.  Credits in this category are not yet criticized or classified, but due to adverse events or aspects of underwriting require closer than normal supervision. Generally, credits should be watch credits in most cases for six months or less as the impact of stress factors are analyzed.
Risk Rating 6: Special Mention
A credit with potential weaknesses that deserves management’s close attention is risk rated a 6.  If left uncorrected, these potential weaknesses will result in deterioration in the capacity to repay debt.  A key distinction between Special Mention and Substandard is that in a Special Mention credit, there are identified weaknesses that pose potential risk(s) to the repayment sources, versus well defined weaknesses that pose risk(s) to the repayment sources.  Assets in this category are expected to be in this category no more than 9-12 months as the potential weaknesses in the credit are resolved.
Risk Rating 7: Substandard
A credit with well defined weaknesses that jeopardize the ability to repay in full is risk rated a 7.  These credits are inadequately protected by either the sound net worth and payment capacity of the borrower or the value of pledged collateral.  These are credits with a distinct possibility of loss.  Loans headed for foreclosure and/or legal action due to deterioration are rated 7 or worse.
Risk Rating 8: Doubtful
A credit with an extremely high probability of loss is risk rated 8.  These credits have all the same critical weaknesses that are found in a substandard loan; however, the weaknesses are elevated to the point that based upon current information, collection or liquidation in full is improbable.  While some loss on doubtful credits is expected, pending events may strengthen a credit making the amount and timing of any loss indeterminate.  In these situations taking the loss is inappropriate until it is clear that the pending event has failed to strengthen the credit and improve the capacity to repay debt.
Risk Rating 9: Loss
A credit that is considered to be currently uncollectible or of such little value that it is no longer a viable Bank asset is risk rated 9.  Losses are taken in the accounting period in which the credit is determined to be uncollectible.  Taking a loss does not mean that a credit has absolutely no recovery or salvage value but, rather, it is not practical or desirable to defer writing off the credit, even though partial recovery may occur in the future.
The following table shows Banner’s portfolio of risk-rated loans and non-risk-rated loans by grade or other characteristic as of December 31, 2014 (in thousands):
	December 31, 2014
	Commercial				Multifamily				Construction				Commercial Business			Agricultural Business			One- to Four-Family Residential			Consumer			Total Loans
	Real Estate				Real Estate				and Land
Risk-rated loans:
Pass (Risk Ratings 1-5) (1)	$	1,375,885			$	166,712			$	395,356			$	691,143		$	234,101		$	527,384		$	346,456		$	3,737,037
Special mention	3,717				—				—				27,453			1,055			63			140			32,428
Substandard	24,123				812				15,650				5,368			3,343			12,447			2,601			64,344
Doubtful	—				—				—				—			—			—			11			11
Total loans	$	1,403,725			$	167,524			$	411,006			$	723,964		$	238,499		$	539,894		$	349,208		$	3,833,820
Performing loans	$	1,402,328			$	167,524			$	409,731			$	723,427		$	236,902		$	529,292		$	347,880		$	3,817,084
Non-performing loans (2)	1,397				—				1,275				537			1,597			10,602			1,328			16,736
Total loans	$	1,403,725			$	167,524			$	411,006			$	723,964		$	238,499		$	539,894		$	349,208		$	3,833,820
(1)	The Pass category includes some performing loans that are part of homogenous pools which are not individually risk-rated.  This includes all consumer loans, all one- to four-family residential loans and, as of December 31, 2014, in the commercial business category, $115 million of credit-scored small business loans.  As loans in these pools become non-performing, they are individually risk-rated.
(2)	Non-performing loans include loans on non-accrual status and loans more than 90 days delinquent, but still accruing interest.
The following table shows Banner’s portfolio of risk-rated loans and non-risk-rated loans by grade or other characteristic as of December 31, 2013 (in thousands):
	December 31, 2013
	Commercial				Multifamily				Construction				Commercial Business			Agricultural Business			One- to Four-Family Residential			Consumer			Total Loans
	Real Estate				Real Estate				and Land
Risk-rated loans:
Pass (Risk Ratings 1-5) (1)	$	1,160,921			$	131,523			$	332,150			$	655,007		$	225,329		$	511,967		$	291,992		$	3,308,889
Special mention	6,614				—				350				10,484			561			—			106			18,115
Substandard	26,979				5,630				18,758				16,669			2,401			17,527			2,924			90,888
Doubtful	544				—				—				9			—			—			—			553
Total loans	$	1,195,058			$	137,153			$	351,258			$	682,169		$	228,291		$	529,494		$	295,022		$	3,418,445
Performing loans	$	1,188,771			$	137,153			$	350,065			$	681,445		$	228,187		$	514,351		$	293,705		$	3,393,677
Non-performing loans (2)	6,287				—				1,193				724			104			15,143			1,317			24,768
Total loans	$	1,195,058			$	137,153			$	351,258			$	682,169		$	228,291		$	529,494		$	295,022		$	3,418,445
(1)	The Pass category includes some performing loans that are part of homogenous pools which are not individually risk-rated.  This includes all consumer loans, all one- to four-family residential loans and, as of December 31, 2013, in the commercial business category, $94 million of credit-scored small business loans.  As loans in these pools become non-performing, they are individually risk-rated.
(2)	Non-performing loans include loans on non-accrual status and loans more than 90 days delinquent, but still accruing interest.
The following tables provide additional detail on the age analysis of Banner’s past due loans as of December 31, 2014 and 2013 (in thousands):
	December 31, 2014
	30–59 Days Past Due				60–89 Days Past Due				90 Days or More Past Due				Total Past Due			Current			Total Loans			Loans 90 Days or More Past Due and Accruing
Commercial real estate:
Owner-occupied	$	—			$	1,984			$	—			$	1,984		$	544,799		$	546,783		$	—
Investment properties	639				—				—				639			856,303			856,942			—
Multifamily real estate	—				—				—				—			167,524			167,524			—
Commercial construction	—				—				—				—			17,337			17,337			—
Multifamily construction	—				—				—				—			60,193			60,193			—
One- to four-family construction	840				—				—				840			219,049			219,889			—
Land and land development:
Residential	759				—				750				1,509			100,926			102,435			—
Commercial	—				—				—				—			11,152			11,152			—
Commercial business	775				35				100				910			723,054			723,964			—
Agricultural business, including secured by farmland	597				466				744				1,807			236,692			238,499			—
One- to four-family residential (1)	877				1,623				7,526				10,026			529,868			539,894			2,095
Consumer:
Consumer secured by one- to four-family	59				60				139				258			221,947			222,205			80
Consumer—other	491				88				293				872			126,131			127,003			—
Total	$	5,037			$	4,256			$	9,552			$	18,845		$	3,814,975		$	3,833,820		$	2,175
	December 31, 2013
	30–59 Days Past Due				60–89 Days Past Due				90 Days or More Past Due				Total Past Due			Current			Total Loans			Loans 90 Days or More Past Due and Accruing
Commercial real estate:
Owner-occupied	$	883			$	550			$	813			$	2,246		$	500,355		$	502,601		$	—
Investment properties	—				—				—				—			692,457			692,457			—
Multifamily real estate	1,845				785				—				2,630			134,523			137,153			—
Commercial construction	—				—				—				—			12,168			12,168			—
Multifamily construction	—				—				—				—			52,081			52,081			—
One- to four-family construction	9				7				4				20			200,844			200,864			—
Land and land development:
Residential	—				—				251				251			75,444			75,695			—
Commercial	—				—				—				—			10,450			10,450			—
Commercial business	2,001				2				299				2,302			679,867			682,169			—
Agricultural business, including secured by farmland	—				—				—				—			228,291			228,291			105
One- to four-family residential (1)	521				2,550				9,142				12,213			517,281			529,494			2,611
Consumer:
Consumer secured by one- to four-family	723				93				918				1,734			171,454			173,188			13
Consumer—other	384				99				131				614			121,220			121,834			131
Total	$	6,366			$	4,086			$	11,558			$	22,010		$	3,396,435		$	3,418,445		$	2,860
-1	One- to four-family loans are not considered past due until they exceed 30 days and are not reflected herein. One- to four-family loans exactly 30 days past due at December 31, 2014 and 2013 were $8 million and $6 million, respectively.
The following tables provide additional information on the allowance for loan losses and loan balances individually and collectively evaluated for impairment at or for the year ended December 31, 2014 (in thousands):
	For the Year Ended December 31, 2014
	Commercial				Multifamily				Construction and Land				Commercial Business			Agricultural Business			One- to Four-Family Residential			Consumer			Unallocated			Total
	Real Estate				Real Estate
Allowance for loan losses:
Beginning balance	$	16,759			$	5,306			$	17,640			$	11,773		$	2,841		$	11,486		$	1,335		$	7,118		$	74,258
Provision for loan losses	1,757				(724		)		6,336				626			(417		)	(5,772		)	90			(1,896		)	—
Recoveries	1,507				—				1,776				988			1,576			618			528			—			6,993
Charge-offs	(1,239		)		(20		)		(207		)		(1,344		)	(179		)	(885		)	(1,470		)	—			(5,344		)
Ending balance	$	18,784			$	4,562			$	25,545			$	12,043		$	3,821		$	5,447		$	483		$	5,222		$	75,907
	December 31, 2014
	Commercial				Multifamily				Construction and Land				Commercial Business			Agricultural Business			One- to Four-Family Residential			Consumer			Unallocated			Total
	Real Estate				Real Estate
Allowance individually evaluated for impairment	$	728			$	86			$	986			$	82		$	—		$	1,014		$	70		$	—		$	2,966
Allowance collectively evaluated for impairment	18,056				4,476				24,559				11,961			3,821			4,433			413			5,222			72,941
Total allowance for loan losses	$	18,784			$	4,562			$	25,545			$	12,043		$	3,821		$	5,447		$	483		$	5,222		$	75,907
	December 31, 2014
	Commercial				Multifamily				Construction				Commercial Business			Agricultural Business			One- to Four-Family Residential			Consumer			Unallocated			Total
	Real Estate				Real Estate				and Land
Loan balances:
Loans individually evaluated for impairment	$	7,171			$	786			$	6,477			$	739		$	744		$	17,848		$	681		$	—		$	34,446
Loans collectively evaluated for impairment	1,396,554				166,738				404,529				723,225			237,755			522,046			348,527			—			3,799,374
Total loans	$	1,403,725			$	167,524			$	411,006			$	723,964		$	238,499		$	539,894		$	349,208		$	—		$	3,833,820
The following tables provide additional information on the allowance for loan losses and loan balances individually and collectively evaluated for impairment at or for the year ended December 31, 2013 (in thousands):
	For the Year Ended December 31, 2013
	Commercial				Multifamily				Construction				Commercial Business			Agricultural Business			One- to Four-Family Residential			Consumer			Unallocated			Total
	Real Estate				Real Estate				and Land
Allowance for loan losses:
Beginning balance	$	15,322			$	4,506			$	14,991			$	9,957		$	2,295		$	16,475		$	1,348		$	11,865		$	76,759
Provision for loan losses	1,639				800				2,195				1,925			97			(2,995		)	1,086			(4,747		)	—
Recoveries	2,367				—				2,275				1,673			697			145			340			—			7,497
Charge-offs	(2,569		)		—				(1,821		)		(1,782		)	(248		)	(2,139		)	(1,439		)	—			(9,998		)
Ending balance	$	16,759			$	5,306			$	17,640			$	11,773		$	2,841		$	11,486		$	1,335		$	7,118		$	74,258
	December 31, 2013
	Commercial				Multifamily				Construction				Commercial Business			Agricultural Business			One- to Four-Family Residential			Consumer			Unallocated			Total
	Real Estate				Real Estate				and Land
Allowance individually evaluated for impairment	$	419			$	1,139			$	1,762			$	222		$	—		$	1,579		$	67		$	—		$	5,188
Allowance collectively evaluated for impairment	16,340				4,167				15,878				11,551			2,841			9,907			1,268			7,118			69,070
Total allowance for loan losses	$	16,759			$	5,306			$	17,640			$	11,773		$	2,841		$	11,486		$	1,335		$	7,118		$	74,258
	December 31, 2013
	Commercial				Multifamily				Construction				Commercial Business			Agricultural Business			One- to Four-Family Residential			Consumer			Unallocated			Total
	Real Estate				Real Estate				and Land
Loan balances:
Loans individually evaluated for impairment	$	10,877			$	5,744			$	12,118			$	1,298		$	—		$	29,834		$	776		$	—		$	60,647
Loans collectively evaluated for impairment	1,184,181				131,409				339,140				680,871			228,291			499,660			294,246			—			3,357,798
Total loans	$	1,195,058			$	137,153			$	351,258			$	682,169		$	228,291		$	529,494		$	295,022		$	—		$	3,418,445

REAL_ESTATE_OWNED_HELD_FOR_SAL

REAL ESTATE OWNED, HELD FOR SALE, NET	12 Months Ended
	Dec. 31, 2014
Real Estate [Abstract]
REAL ESTATE OWNED, HELD FOR SALE, NET	REAL ESTATE OWNED, HELD FOR SALE, NET
	The following table presents the changes in real estate owned (REO), net of valuation allowance, for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Years Ended December 31
		2014			2013			2012
	Balance, beginning of period	$	4,044		$	15,778		$	42,965
	Additions from loan foreclosures	3,264			3,166			13,930
	Additions from capitalized costs	30			348			300
	Proceeds from dispositions of REO	(4,923		)	(16,944		)	(40,965		)
	Gain on sale of REO	973			2,481			4,725
	Valuation adjustments in the period	(36		)	(785		)	(5,177		)
	Balance, end of period	$	3,352		$	4,044		$	15,778
	The following table shows REO by type and geographic location by state as of December 31, 2014 (dollars in thousands):
		Washington			Oregon			Idaho			Total
	Land development—residential	259			1,271			32			1,562
	One- to four-family real estate	1,435			355			—			1,790
	Total REO	$	1,694		$	1,626		$	32		$	3,352
	Percent of total REO	50.5		%	48.5		%	1		%	100		%

PROPERTY_AND_EQUIPMENT_NET

PROPERTY AND EQUIPMENT, NET	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
PROPERTY AND EQUIPMENT, NET	PROPERTY AND EQUIPMENT, NET
	Land, buildings and equipment owned by the Company and its subsidiaries at December 31, 2014 and 2013 are summarized as follows (in thousands):
		31-Dec
		2014			2013
	Land	$	21,969		$	19,974
	Buildings and leasehold improvements	98,901			99,351
	Furniture and equipment	72,152			65,912
		193,022			185,237
	Less accumulated depreciation	(101,837		)	(94,970		)
	Property and equipment, net	$	91,185		$	90,267
	The Company’s depreciation expense related to property and equipment was $8.1 million, $7.5 million, and $7.8 million for the years ended December 31, 2014, 2013 and 2012, respectively.  The Company’s rental expense was $7.6 million, $7.3 million, and $7.1 million for the years ended December 31, 2014, 2013 and 2012, respectively.
	The Company’s obligations under long-term property leases are as follows:
	Year		Amount
	2015		$ 7.6 million
	2016		5.7 million
	2017		4.7 million
	2018		4.2 million
	2019		3.4 million
	Thereafter		9.6 million
	Total		$ 35.2 million

DEPOSITS

DEPOSITS	12 Months Ended
	Dec. 31, 2014
Banking and Thrift [Abstract]
DEPOSITS	DEPOSITS
	Deposits consist of the following at December 31, 2014 and 2013 (dollars in thousands):
		31-Dec
		2014				2013
		Amount		Percent of		Amount			Percent of
				Total					Total
	Non-interest-bearing checking	$	1,298,866	33.3	%	$	1,115,346		30.8	%
	Interest-bearing checking	439,480		11.3		422,910			11.7
	Regular savings accounts	901,142		23.1		798,764			22.1
	Money market accounts	488,946		12.5		408,211			11.3
	Total transaction and savings accounts	3,128,434		80.2		2,745,231			75.9
	Certificates of deposit:
	Up to 1.00%	643,065		16.5		723,891			20
	1.01% to 2.00%	87,661		2.3		95,663			2.6
	2.01% to 3.00%	32,184		0.8		43,062			1.2
	3.01% to 4.00%	3,024		0.1		6,663			0.2
	4.01% and greater	4,582		0.1		3,416			0.1
	Total certificates of deposit	770,516		19.8		872,695			24.1
	Total deposits	$	3,898,950	100	%	$	3,617,926		100	%
	Included in total deposits:
	Public fund transaction accounts	$	102,854	2.6	%	$	87,521		2.4	%
	Public fund interest-bearing certificates	35,346		0.9		51,465			1.4
	Total public deposits	$	138,200	3.5	%	$	138,986		3.8	%
	Total brokered deposits	$	4,799	0.1	%	$	4,291		0.1	%
	Deposits at December 31, 2014 and 2013 included deposits from the Company’s directors, executive officers and related entities totaling $6.2 million and $6.7 million, respectively.
	Certificate of deposit accounts by total balance at December 31, 2014 and 2013 were as follows (in thousands):
		31-Dec
		2014		2013
	Certificates of deposit less than $100,000	$	358,189	$	386,745
	Certificates of deposit $100,000 through $250,000	275,156		308,130
	Certificates of deposit more than $250,000	137,171		177,820
	Total certificates of deposit	$	770,516	$	872,695
	Certificates of deposit of $250,000 and greater totaled $141 million and $184 million at December 31, 2014 and 2013, respectively.
	Scheduled maturities and weighted average interest rates of certificate accounts at December 31, 2014 and 2013 are as follows (dollars in thousands):
		31-Dec
		2014				2013
		Amount		Weighted		Amount			Weighted
				Average Rate					Average Rate
	Maturing in one year or less	$	564,501	0.46	%	$	660,394		0.47	%
	Maturing after one year through two years	117,724		0.89		117,789			1.05
	Maturing after two years through three years	46,378		1.19		47,362			1.34
	Maturing after three years through four years	20,016		1.42		26,443			1.56
	Maturing after four years through five years	17,338		1.22		17,075			1.34
	Maturing after five years	4,559		2.09		3,632			1.78
	Total certificates of deposit	$	770,516	1.06	%	$	872,695		0.65	%
	The following table sets forth the deposit activities for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Years Ended December 31
		2014		2013			2012
	Balance at beginning of year	$	3,617,926	$	3,557,804		$	3,475,654
	Net increase before interest credited	273,446		50,385			67,043
	Interest credited	7,578		9,737			15,107
	Net increase in deposits	281,024		60,122			82,150
	Balance at end of year	$	3,898,950	$	3,617,926		$	3,557,804
	Deposit interest expense by type for the years ended December 31, 2014, 2013 and 2012 was as follows (in thousands):
		Years Ended December 31
		2014		2013			2012
	Certificates of deposit (1)	$	5,145	$	6,836		$	11,458
	Demand, interest-bearing checking and money market accounts	1,123		1,329			1,824
	Regular savings	1,310		1,572			1,825
		$	7,578	$	9,737		$	15,107
	(1)	Interest expense on certificate of deposit accounts with balances of $100,000 or more totaled $3.1 million, $4.0 million, and $6.7 million for the years ended December 31, 2014, 2013 and 2012, respectively.

ADVANCES_FROM_FEDERAL_HOME_LOA

ADVANCES FROM FEDERAL HOME LOAN BANK OF SEATTLE	12 Months Ended
	Dec. 31, 2014
Advances from Federal Home Loan Banks [Abstract]
ADVANCES FROM FEDERAL HOME LOAN BANK OF SEATTLE	ADVANCES FROM FEDERAL HOME LOAN BANK OF SEATTLE
	Utilizing a blanket pledge, qualifying loans receivable at December 31, 2014 and 2013, were pledged as security for FHLB borrowings and there were no securities pledged as collateral as of December 31, 2014 or 2013.  At December 31, 2014 and 2013, FHLB advances were scheduled to mature as follows (dollars in thousands):
		31-Dec
		2014						2013
		Amount			Weighted Average Rate			Amount				Weighted Average Rate
	Maturing in one year or less	$	32,000		0.27	%		$	27,000			0.23	%
	Maturing after one year through three years	—			—			—				—
	Maturing after three years through five years	—			—			—				—
	Maturing after five years	196			5.94			203				5.94
	Total FHLB advances, at par	32,196			0.27			27,203				0.27
	Fair value adjustment	54						47
	Total FHLB advances, carried at fair value	$	32,250					$	27,250
	The maximum, average outstanding and year-end balances (excluding fair value adjustments) and average interest rates on advances from the FHLB were as follows at or for the years ended December 31, 2014, 2013 and 2012 (dollars in thousands):
		At or For the Years Ended December 31
		2014			2013				2012
	Maximum outstanding at any month end, at par	$	105,450		$	60,377			$	10,216
	Average outstanding, at par	39,121			18,935				10,215
	Year-end outstanding, at par	32,196			27,203				10,210
	Weighted average interest rates:
	Annual	0.32		%	0.52		%		2.49		%
	End of period	0.27		%	0.27		%		2.45		%
	Interest expense during the period	$	125		$	99			$	254
	As of December 31, 2014, Banner Bank has established a borrowing line with the FHLB to borrow up to 35% of its total assets, contingent on having sufficient qualifying collateral and ownership of FHLB stock.  Islanders Bank has a similar line of credit, although it may borrow up to 25% of its total assets, also contingent on collateral and FHLB stock.  At December 31, 2014, the maximum total FHLB credit line was $901 million and $23 million for Banner Bank and Islanders Bank, respectively.

OTHER_BORROWINGS

OTHER BORROWINGS	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
OTHER BORROWINGS	OTHER BORROWINGS
	Other borrowings consist of retail repurchase agreements, other term borrowings and Federal Reserve Bank borrowings.
	Retail Repurchase Agreements:  At December 31, 2014, retail repurchase agreements carry interest rates ranging from 0.15% to 0.40%, and are secured by the pledge of certain mortgage-backed and agency securities with a carrying value of $99 million.  Banner Bank has the right to pledge or sell these securities, but they must replace them with substantially the same security.
	Federal Reserve Bank of San Francisco and Other Borrowings:  Banner Bank periodically borrows funds on an overnight basis from the Federal Reserve Bank through the Borrower-In-Custody (BIC) program.  Such borrowings are secured by a pledge of eligible loans.  At December 31, 2014, based upon available unencumbered collateral, Banner Bank was eligible to borrow $639 million from the Federal Reserve Bank, although, at that date, as well as at December 31, 2013, the Bank had no funds borrowed under this or other borrowing arrangements.
	There were no wholesale repurchase agreements, other short-term borrowings, or any Fed Funds, outstanding as of December 31, 2014 and 2013.
	A summary of all other borrowings at December 31, 2014 and 2013 by the period remaining to maturity is as follows (dollars in thousands):
		At or for the Years Ended December 31
		2014				2013
		Amount		Weighted		Amount			Weighted
				Average Rate					Average Rate
	Retail repurchase agreements:
	Maturing in one year or less	$	77,185	0.2	%	$	83,056		0.2	%
	Maturing after one year through two years	—		—		—			—
	Maturing after two years	—		—		—			—
	Total year-end outstanding	$	77,185	0.2		$	83,056		0.2
	Average outstanding	$	83,965	0.2		$	84,877		0.23
	Maximum outstanding at any month-end	89,921		n/a		91,964			n/a
	The table below summarizes interest expense for other borrowings for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Years Ended December 31
		2014		2013			2012
	Retail repurchase agreements	$	172	$	192		$	281
	FDIC guaranteed debt	—		—			477
	Total expense	$	172	$	192		$	758

JUNIOR_SUBORDINATED_DEBENTURES

JUNIOR SUBORDINATED DEBENTURES AND MANDATORILY REDEEMABLE TRUST PREFERRED SECURITIES

12 Months Ended

Dec. 31, 2014

Other Liabilities Disclosure [Abstract]

JUNIOR SUBORDINATED DEBENTURES AND MANDATORILY REDEEMABLE TRUST PREFERRED SECURITIES

JUNIOR SUBORDINATED DEBENTURES AND MANDATORILY REDEEMABLE TRUST PREFERRED SECURITIES

At December 31, 2014, six wholly-owned subsidiary grantor trusts, Banner Capital Trust II, III, IV, V, VI and VII (BCT II, BCT III, BCT IV, BCT V, BCT VI and BCT VII (collectively, the Trusts)), established by the Company had issued $120 million of trust preferred securities to third parties, as well as $3.7 million of common capital securities, carried among other assets, which were issued to the Company.  Trust preferred securities and common capital securities accrue and pay distributions periodically at specified annual rates as provided in the indentures.  The Trusts used the proceeds from the offerings to purchase a like amount of junior subordinated debentures (the Debentures) of the Company.  The Debentures are the sole assets of the Trusts.  The Company’s obligations under the debentures and related documents, taken together, constitute a full and unconditional guarantee by the Company of the obligations of the Trusts.  The trust preferred securities are mandatorily redeemable upon the maturity of the Debentures, or upon earlier redemption as provided in the indentures.  The Company has the right to redeem the Debentures in whole on or after specific dates, at a redemption price specified in the indentures plus any accrued but unpaid interest to the redemption date.  All of the trust preferred securities issued by the Trusts qualified as Tier 1 capital as of December 31, 2014, under guidance issued by the Board of Governors of the Federal Reserve System.  At December 31, 2014, the Trusts comprised $74.3 million, or 11.8% of the Company’s total risk-based capital.

The following table is a summary of trust preferred securities at December 31, 2014 (dollars in thousands):

Name of Trust

Aggregate Liquidation Amount of Trust Preferred Securities

Aggregate Liquidation Amount of Common Capital Securities

Aggregate Principal Amount of Junior Subordinated Debentures

Stated Maturity

Current Interest Rate

Reset Period

Interest Rate Spread

Interest Deferral Period

Redemption Option

Banner Capital Trust II

$

15,000

$

464

$

15,464

2033

3.58

%

Quarterly

Three-month

20 Consecutive

On or after

LIBOR + 3.35%

Quarters

7-Jan-08

Banner Capital Trust III

15,000

465

15,465

2033

3.13

Quarterly

Three-month

20 Consecutive

On or after

LIBOR + 2.90%

Quarters

8-Oct-08

Banner Capital Trust IV

15,000

465

15,465

2034

3.08

Quarterly

Three-month

20 Consecutive

On or after

LIBOR + 2.85%

Quarters

7-Apr-09

Banner Capital Trust V

25,000

774

25,774

2035

1.8

Quarterly

Three-month

20 Consecutive

On or after

LIBOR + 1.57%

Quarters

23-Nov-10

Banner Capital Trust VI

25,000

774

25,774

2037

1.86

Quarterly

Three-month

20 Consecutive

On or after

LIBOR + 1.62%

Quarters

1-Mar-12

Banner Capital Trust VII

25,000

774

25,774

2037

1.62

Quarterly

Three-month

20 Consecutive

On or after

LIBOR + 1.38%

Quarters

31-Jul-12

Total TPS liability at par

$

120,000

$

3,716

123,716

2.32

%

Fair value adjustment

(45,715

)

Total TPS liability at fair value

$

78,001

INCOME_TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES
	The following table presents the components of the provision for income tax (benefit) expense included in the Consolidated Statement of Operations for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Years Ended December 31
		2014				2013				2012
	Current	$	24,855			$	12,121			$	10,759
	Deferred	1,365				10,407				841
	Increase (decrease) in valuation allowance	—				—				(36,385		)
	Provision for (benefit from) income taxes	$	26,220			$	22,528			$	(24,785	)
	The following tables present the reconciliation of the provision for income taxes computed at the federal statutory rate to the actual effective rate for the years ended December 31, 2014, 2013 and 2012 (dollars in thousands):
		Years Ended December 31
		2014				2013				2012
	Provision for (benefit from) income taxes computed at federal statutory rate	$	28,134			$	24,179			$	14,034
	Increase (decrease) in taxes due to:
	Tax-exempt interest	(2,084		)		(1,633		)		(1,710		)
	Investment in life insurance	(626		)		(707		)		(894		)
	State income taxes (benefit), net of federal tax offset	916				824				539
	Tax credits	(661		)		(636		)		(788		)
	Valuation allowance	—				—				(36,385		)
	Other	541				501				419
	Provision for (benefit from) income taxes	$	26,220			$	22,528			$	(24,785	)
		Years Ended December 31
		2014			2013			2012
	Federal income tax statutory rate	35	%		35	%		35	%
	Increase (decrease) in tax rate due to:
	Tax-exempt interest	(2.6	)		(2.4	)		(4.3	)
	Investment in life insurance	(0.8	)		(1.0	)		(2.2	)
	State income taxes (benefit), net of federal tax offset	1.1			1.2			1.3
	Tax credits	(0.8	)		(0.9	)		(2.0	)
	Valuation allowance	—			—			(90.7	)
	Other	0.7			0.7			1.1
	Effective income tax rate	32.6	%		32.6	%		(61.8	)%
	The following table reflects the effect of temporary differences that gave rise to the components of the net deferred tax asset as of December 31, 2014 and 2013 (in thousands):
		31-Dec
		2014				2013
	Deferred tax assets:
	REO and loan loss reserves	$	26,536			$	17,326
	Deferred compensation	9,223				7,305
	Net operating loss carryforward	17,577				27,639
	Low income housing tax credits	3,676				3,676
	State net operating losses	1,009				957
	Other	1,344				1,235
	Total deferred tax assets	59,365				58,138
	Deferred tax liabilities:
	FHLB stock dividends	(4,805		)		(5,875		)
	Depreciation	(4,479		)		(4,074		)
	Deferred loan fees, servicing rights and loan origination costs	(7,843		)		(6,444		)
	Intangibles	(975		)		(833		)
	Financial instruments accounted for under fair value accounting	(15,611		)		(15,118		)
	Loan discount	(1,190		)		—
	Total deferred tax liabilities	(34,903		)		(32,344		)
	Deferred income tax asset	24,462				25,794
	Unrealized loss on securities—available-for-sale	145				1,685
	Deferred tax asset, net	$	24,607			$	27,479
	At December 31, 2014, the Company has federal and state net operating loss carryforwards of approximately $50.2 million and $21.2 million, respectively, which will expire, if unused, by the end of 2033.  The Company has federal general business credit carryforwards of $2.7 million, which will expire, if unused, by the end of 2031. The Company also has alternative minimum tax credit carryforwards of approximately $900,000, which are available to reduce future federal regular income taxes, if any, over an indefinite period. At December 31, 2013, the Company had federal and state net operating loss carryforwards of approximately $79.0 million and $20.4 million, respectively, and federal general business credits carryforwards of $2.7 million. The Company also had alternative minimum tax credit carryforwards of approximately $900,000.
	As a consequence of our capital raise in June 2010, the Company experienced a change in control within the meaning of Section 382 of the Internal Revenue Code of 1986, as amended. Section 382 limits the ability of a corporate taxpayer to use net operating loss carryforwards, general business credit, and recognized built-in-losses incurred prior to the change in control against income earned after the change in control. As a result of the Section 382 limitation, the Company expects it will be able to utilize approximately $6.9 million of net operating loss carryforwards on an annual basis. Based on its analysis, the Company does not believe the change in control will impact its ability to utilize all of the available net operating loss carryforwards, general business credit, and recognized built-in-losses.
	Retained earnings (accumulated deficits) at December 31, 2014 and 2013 include approximately $5.4 million in tax basis bad debt reserves for which no income tax liability has been booked.  In the future, if this tax bad debt reserve is used for purposes other than to absorb bad debts or the Company no longer qualifies as a bank or is completely liquidated, the Company will incur a federal tax liability at the then-prevailing corporate tax rate, established as $1.9 million at December 31, 2014.
	As of December 31, 2014, the Company had reduced its previous year's tax receivable by $9.8 million as a result of the approval of a closing agreement with the IRS related to amended 2006, 2008 and 2009 federal income tax returns.  Review of the amended federal returns was completed by the Internal Revenue Service (IRS) in 2013 and the Company signed a closing agreement with the IRS related to refund claims of $9.8 million, which was received in 2014.

EMPLOYEE_BENEFIT_PLANS

EMPLOYEE BENEFIT PLANS	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
EMPLOYEE BENEFIT PLANS	EMPLOYEE BENEFIT PLANS
	Employee Retirement Plans: Substantially all of the Company’s employees are eligible to participate in its 401(k)/Profit Sharing Plan, a defined contribution and profit sharing plan sponsored by the Company. Employees may elect to have a portion of their salary contributed to the plan in conformity with Section 401(k) of the Internal Revenue Code. At the discretion of the Company’s Board of Directors, the Company may elect to make matching and/or profit sharing contributions for the employees’ benefit. For the years ended December 31, 2014, 2013 and 2012, $1.4 million, $1.0 million and, $43,000 respectively, was expensed for 401(k) contributions. The Board of Directors has elected to make a 4% of eligible compensation matching contribution for 2015.
	Supplemental Retirement and Salary Continuation Plans:  Through the Banks, the Company is obligated under various non-qualified deferred compensation plans to help supplement the retirement income of certain executives, including certain retired executives, selected by resolution of the Banks’ Boards of Directors or in certain cases by the former directors of acquired banks.  These plans are unfunded, include both defined benefit and defined contribution plans, and provide for payments after the executive’s retirement.  In the event of a participant employee’s death prior to or during retirement, the Bank is obligated to pay to the designated beneficiary the benefits set forth under the plan.  For the years ended December 31, 2014, 2013 and 2012, expense recorded for supplemental retirement and salary continuation plan benefits totaled $1.2 million, $1.5 million, and $879,000, respectively.  At December 31, 2014 and 2013, liabilities recorded for the various supplemental retirement and salary continuation plan benefits totaled $14.2 million and $13.6 million, respectively, and are recorded in a deferred compensation liability account.
	Deferred Compensation Plans and Rabbi Trusts:  The Company and the Banks also offer non-qualified deferred compensation plans to members of their Boards of Directors and certain employees.  The plans permit each participant to defer a portion of director fees, non-qualified retirement contributions, salary or bonuses for future receipt.  Compensation is charged to expense in the period earned.  In connection with its acquisitions, the Company also assumed liability for certain deferred compensation plans for key employees, retired employees and directors.
	In order to fund the plans’ future obligations, the Company has purchased life insurance policies or other investments, including Banner Corporation common stock, which in certain instances are held in irrevocable trusts commonly referred to as “Rabbi Trusts.”  As the Company is the owner of the investments and the beneficiary of the insurance policies, and in order to reflect the Company’s policy to pay benefits equal to the accumulations, the assets and liabilities are reflected in the Consolidated Statements of Financial Condition.  Banner Corporation common stock held for such plans is reported as a contra-equity account and was recorded at an original cost of $6.7 million at December 31, 2014 and $7.1 million at December 31, 2013.  At December 31, 2014 and 2013, liabilities recorded in connection with deferred compensation plan benefits totaled $8.2 million ($6.7 million in contra-equity) and $8.5 million ($7.1 million in contra-equity), respectively, and are recorded in deferred compensation or equity as appropriate.
	The Banks have purchased, or acquired through mergers, life insurance policies in connection with the implementation of certain executive supplemental retirement, salary continuation and deferred compensation retirement plans, as well as additional policies not related to any specific plan. These policies provide protection against the adverse financial effects that could result from the death of a key employee and provide tax-exempt income to offset expenses associated with the plans.  It is the Banks’ intent to hold these policies as a long-term investment.  However, there will be an income tax impact if the Banks choose to surrender certain policies.  Although the lives of individual current or former management-level employees are insured, the Banks are the owners and sole or partial beneficiaries.  At December 31, 2014 and 2013, the cash surrender value of these policies was $63.8 million and $61.9 million, respectively.  The Banks are exposed to credit risk to the extent an insurance company is unable to fulfill its financial obligations under a policy.  In order to mitigate this risk, the Banks use a variety of insurance companies and regularly monitor their financial condition.

EMPLOYEE_STOCK_OWNERSHIP_PLAN_

EMPLOYEE STOCK OWNERSHIP PLAN AND TRUST	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
EMPLOYEE STOCK OWNERSHIP PLAN AND TRUST	EMPLOYEE STOCK OWNERSHIP PLAN AND TRUST
	In 1995, the Company established an ESOP and related trust for eligible employees of Banner Bank as of January 1, 1995 and eligible employees of the Banks or Company employed after such date. The ESOP borrowed $8.7 million from the Company in order to purchase the common stock.  The loan was repaid principally from the Company’s contributions to the ESOP. Shares were released to participants for allocation based on the cumulative debt service paid to the Company by the ESOP divided by cumulative debt service paid to date plus the scheduled debt service remaining.  No ESOP contributions were made for the years ended December 31, 2014, 2013 or 2012 and no payments were made on the loan in those years. On December 17, 2013, the Company's Board of Directors elected to terminate the ESOP effective January 1, 2014. The allocated shares held by the ESOP were distributed to the participants of the plan during 2014. The unallocated shares held by the ESOP were forfeited and redeemed and the outstanding balance of the loan was canceled. Termination of the ESOP had no impact on the net equity position of the Company or its current and future operating results.

STOCKBASED_COMPENSATION_PLANS

STOCK-BASED COMPENSATION PLANS	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
STOCK-BASED COMPENSATION PLANS	STOCK-BASED COMPENSATION PLANS
	The Company operates the following stock-based compensation plans as approved by the shareholders: the 1996 Stock Option Plan, the 1998 Stock Option Plan and 2001 Stock Option Plan (collectively, SOPs), the 2012 Restricted Stock and Incentive Bonus Plan, and the 2014 Omnibus Incentive Plan.  In addition, the Board approved in 2006 the Banner Corporation Long-Term Incentive Plan. The purpose of these plans is to promote the success and enhance the value of the Company by providing a means for attracting and retaining highly skilled employees, officers and directors of Banner Corporation and its affiliates and linking their personal interests with those of the Company's shareholders. Under these plans the Company currently has outstanding restricted stock grants, stock options and stock appreciation rights.
	Restricted Stock Grants: Under the 2012 Restricted Stock and Incentive Bonus Plan, which was initially approved on April 24, 2012, the Company is authorized to issue up to 300,000 shares of its common stock to provide a means for attracting and retaining highly skilled officers of Banner Corporation and its affiliates. Shares granted under the Plan have a minimum vesting period of three years. The Plan will continue in effect for a term of ten years, after which no further awards may be granted. The 2012 Restricted Stock and Incentive Bonus Plan was amended on April 23, 2013 to provide for the ability to grant (1) cash-denominated incentive-based awards payable in cash or common stock, including those that are eligible to qualify as qualified performance-based compensation for the purposes of Section 162(m) of the IRS Code and (2) restricted stock awards that qualify as qualified performance-based compensation for the purposes of Section 162(m) of the IRS Code. Vesting requirements may include time-based conditions, performance-based conditions, or market-based conditions. As of December 31, 2014, the Company had granted 266,778 shares of restricted stock, net of forfeitures, from the 2012 Restricted Stock and Incentive Bonus Plan, of which 81,241 shares had vested and 185,537 shares remain unvested.
	Banner Corporation 2014 Omnibus Incentive Plan: The 2014 Plan was approved by shareholders on April 22, 2014. The 2014 Plan provides for the grant of incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock, restricted stock units, performance shares, performance units, other stock-based awards and other cash awards, and provides for vesting requirements which may include time-based or performance-based conditions. The Company has reserved 900,000 shares of its common stock for issuance under the 2014 Plan in connection with exercise of awards. As of December 31, 2014, 9,352 shares had been granted to directors under the 2014 Omnibus Incentive Plan.
	The expense associated with all restricted stock grants was $2.7 million, $1.5 million and $434,000, respectively, for the years ended December 31, 2014, 2013 and 2012.  Unrecognized compensation expense for these awards as of December 31, 2014 was $3.9 million and will be amortized over the next 30 months.
	A summary of the Company's Restricted Stock award activity during the years ended December 31, 2012, 2013 and 2014 follows:
		Shares			Weighted Average
					Grant-Date
					Fair Value
	Unvested at December 31, 2011	28,735			$	14.5
	Granted	92,035			21.77
	Vested	(11,419	)		14.6
	Forfeited	(1,500	)		21.94
	Unvested at December 31, 2012	107,851			20.59
	Granted	98,891			30.81
	Vested	(42,250	)		19.85
	Forfeited	—			—
	Unvested at December 31, 2013	164,492			26.94
	Granted	90,181			40.07
	Vested	(56,307	)		24.81
	Forfeited	(3,260	)		31
	Unvested at December 31, 2014	195,106			32.83
	Stock Options:  Under the SOPs, Banner reserved 2,284,186 shares for issuance pursuant to the exercise of stock options to be granted to directors and employees.  Authority to grant additional options under the 1998 Stock Option Plan terminated on July 24, 2008 with all options having been granted.  Authority to grant additional options under the 2001 Stock Option Plan terminated on April 20, 2011.  The exercise price of the stock options is set at 100% of the fair market value of the stock price on the date of grant.  Options granted vest at a rate of 20% per year from the date of grant and any unexercised incentive stock options will expire ten years after date of grant or 90 days after employment or service ends.
	During the years ended December 31, 2014, 2013 and 2012, the Company did not grant any stock options.  Additionally, there were no significant modifications made to any stock option grants during the period.  The fair values of stock options granted are amortized as compensation expense on a straight-line basis over the vesting period of the grant.
	For the years ended December 31, 2014 and 2013, there were no stock option compensation expenses recorded. For the year ended December 31, 2012, stock-based compensation costs related to the SOPs was $7,000.  The SOPs' stock option grant compensation costs are generally based on the fair value calculated from the Black-Scholes option pricing on the date of the grant award.  The Black-Scholes model assumes an expected stock price volatility based on the historical volatility at the date of the grant and an expected term based on the remaining contractual life of the vesting period.  The Company bases the estimate of risk-free interest rate on the Treasury's Constant Maturities Indices in effect at the time of the grant.  The dividend yield is based on the current quarterly dividend in effect at the time of the grant.
	The Company is required to estimate potential forfeitures of stock option grants and adjust compensation cost recorded accordingly.  The estimate of forfeitures is adjusted over the requisite service period to the extent that actual forfeitures differ, or are expected to differ, from such estimates.  Changes in estimated forfeitures are recognized through a cumulative catch-up adjustment in the period of change and also impact the amount of stock compensation expense to be recognized in future periods.
	A summary of the Company’s stock option award activity for the years ended December 31, 2012, 2013 and 2014 follows:
		Shares			Weighted			Weighted		Aggregate
					Average			Average		Intrinsic Value
					Exercise Price			Remaining
								Contractual
								Term, In Years
	Outstanding at December 31, 2011	51,729			$	168.98		2.4		n/a
	Granted	—			—
	Exercised	—			—
	Forfeited	(9,208	)		145.97
	Outstanding at December 31, 2012	42,521			173.98			1.75		n/a
	Granted	—			—
	Exercised	—			—
	Forfeited	(16,157	)		121.29
	Outstanding at December 31, 2013	26,364			206.27			1.58		n/a
	Granted	—			—
	Exercised	—			—
	Forfeited	(15,700	)		206.44
	Outstanding at December 31, 2014	10,664			206.03			1.9		n/a
	Outstanding at December 31, 2014, net of expected forfeitures	—			—			n/a		n/a
	Exercisable at December 31, 2014	10,664			206.03			1.9
	The intrinsic value of stock options is calculated as the amount by which the market price of Banner's common stock exceeds the exercise price at the time of exercise or the end of the period as applicable.
	At December 31, 2014, financial data pertaining to outstanding stock options was as follows:
	Exercise Price		Weighted Average Exercise Price of Option Shares Granted				Number of Option Shares Granted		Weighted Average Option Shares Vested and Exercisable			Weighted Average Exercise Price of Option Shares Exercisable		Remaining Contractual Life
	$0.00 to $184.00		$	176.72			2,593		2,593			$	176.72	0.1 years
	$184.01 to $220.00		212.96				8,071		8,071			212.96		1.8 years
			206.44				10,664		10,664			206.27
	During the year ended December 31, 2014, there were no exercises of stock options.  Cash was not used to settle any equity instruments previously granted.  The Company issues shares from authorized but unissued shares upon the exercise of stock options.  The Company does not currently expect to repurchase shares from any source to satisfy such obligations under the SOPs.
	The following are the stock-option compensation costs recognized in the Company’s consolidated statements of operations for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Years Ended December 31
		2014				2013			2012
	Salary and employee benefits	$	—			$	—		$	11
	Decrease in provision for income taxes	—				—			(4		)
	Decrease in equity, net	$	—			$	—		$	7
	Banner Corporation Long-Term Incentive Plan: In June 2006, the Board of Directors adopted the Banner Corporation Long-Term Incentive Plan effective July 1, 2006. The Plan is an account-based type of benefit, the value of which is directly related to changes in the value of Company common stock, dividends declared on Company common stock and changes in Banner Bank’s average earnings rate, and is considered a stock appreciation right (SAR). Each SAR entitles the holder to receive cash, upon vesting, equal to the excess of the fair market value of a share of the Company’s common stock on the date of maturity of the SAR over the fair market value of such share on the date granted plus, for some grants, the dividends declared on the stock from the date of grant to the date of vesting. The primary objective of the Plan is to create a retention incentive by allowing officers who remain with the Company or the Banks for a sufficient period of time to share in the increases in the value of Company stock. The Company re-measures the fair value of SARs each reporting period until the award is settled and recognizes changes in fair value and vesting in compensation expense.  The Company recognized compensation expense of $89,000, $1.0 million, and $314,000, respectively, for the years ended December 31, 2014, 2013 and 2012 related to the increase in the fair value of SARs and additional vesting during the period.  At December 31, 2014, the aggregate liability related to SARs was $1.1 million and is included in deferred compensation.

PREFERRED_STOCK_AND_RELATED_WA

PREFERRED STOCK AND RELATED WARRANT	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
PREFERRED STOCK AND RELATED WARRANT	PREFERRED STOCK AND RELATED WARRANT
	On November 21, 2008, as part of the Capital Purchase Program established by the U.S. Treasury under the Emergency Economic Stabilization Act of 2008 (the EESA), the Company entered into a Purchase Agreement with Treasury pursuant to which the Company issued and sold to Treasury 124,000 shares of Series A Preferred Stock, having a liquidation preference of $1,000 per share ($124 million liquidation preference in the aggregate), and as more fully explained below, a ten-year warrant to purchase up to 243,998 shares (post reverse-split) of the Company’s common stock, par value $0.01 per share, at an initial exercise price of $76.23 per share (post reverse-split), for an aggregate purchase price of $18.6 million in cash. The warrant issued is immediately exercisable, in whole or in part, has a ten-year term and the number of shares is subject to certain customary anti-dilution and other adjustments.  The warrant is not subject to any contractual restrictions on transfer.  The Company has granted the warrant holder piggyback registration rights for the warrant and the common stock underlying the warrant and has agreed to take such other steps as may be reasonably requested to facilitate the transfer of the warrant and the common stock underlying the warrant.  The holder of the warrant is not entitled to any common stockholder rights.
	On March 29, 2012, the Company's $124 million of Series A Preferred Stock was sold by the Treasury as part of its efforts to manage and recover its investments under the Troubled Assets Relief Program (TARP).  While the sale of these preferred shares to new owners did not result in any proceeds to the Company and did not change the Company's capital position or accounting for these securities, it did eliminate restrictions put in place by the Treasury on TARP recipients.  During the year ended December 31, 2012, the Company repurchased or redeemed its Series A Preferred Stock. The related warrants to purchase up to $18.6 million in Banner common stock (243,998 shares) were sold by the Treasury at public auction in June 2013. That sale did not change the Company's capital position and did not have any impact on the financial accounting and reporting for these securities.

REGULATORY_CAPITAL_REQUIREMENT

REGULATORY CAPITAL REQUIREMENTS	12 Months Ended
	Dec. 31, 2014
Regulatory Capital Requirements [Abstract]
REGULATORY CAPITAL REQUIREMENTS	REGULATORY CAPITAL REQUIREMENTS
	Banner Corporation is a bank holding company registered with the Federal Reserve.  Bank holding companies are subject to capital adequacy requirements of the Federal Reserve under the Bank Holding Company Act of 1956, as amended (BHCA), and the regulations of the Federal Reserve.  Banner Bank and Islanders Bank, as state-chartered federally insured commercial banks, are subject to the capital requirements established by the FDIC.  The Federal Reserve requires Banner to maintain capital adequacy that generally parallels the FDIC requirements.
	Federal statutes establish a supervisory framework based on five capital categories:  well capitalized, adequately capitalized, undercapitalized, significantly undercapitalized and critically undercapitalized.  An institution’s category depends upon where its capital levels are in relation to relevant capital measures, which include a risk-based capital measure, a leverage ratio capital measure and certain other factors.  The federal banking agencies have adopted regulations that implement this statutory framework.  Under these regulations, an institution is treated as well capitalized if its ratio of total capital to risk-weighted assets is 10% or more, its ratio of core capital to risk-weighted assets is 6% or more, its ratio of core capital to adjusted total assets (leverage ratio) is 5% or more, and it is not subject to any federal supervisory order or directive to meet a specific capital level.  In order to be adequately capitalized, an institution must have a total risk-based capital ratio of not less than 8%, a core capital to risk-weighted assets ratio of not less than 4%, and a leverage ratio of not less than 4%.  Any institution which is neither well capitalized nor adequately capitalized is considered undercapitalized.
	Undercapitalized institutions are subject to certain prompt corrective action requirements, regulatory controls and restrictions which become more extensive as an institution becomes more severely undercapitalized.  Failure by either Banner Bank and Islanders Bank to comply with applicable capital requirements would, if unremedied, result in progressively more severe restrictions on their respective activities and lead to enforcement actions, including, but not limited to, the issuance of a capital directive to ensure the maintenance of required capital levels and, ultimately, the appointment of the FDIC as receiver or conservator.  Banking regulators will take prompt corrective action with respect to depository institutions that do not meet minimum capital requirements.  Additionally, approval of any regulatory application filed for their review may be dependent on compliance with capital requirements.
	FDIC regulations recognize two types, or tiers, of capital:  core (Tier 1) capital and supplementary (Tier 2) capital.  Tier 1 capital generally includes common stockholders’ equity and qualifying noncumulative perpetual preferred stock, less most intangible assets.  Tier 2 capital, which is recognized up to 100% of Tier 1 capital for risk-based capital purposes (after any deductions for disallowed intangibles and disallowed deferred tax assets), includes such items as qualifying general loan loss reserves (up to 1.25% of risk-weighted assets), cumulative perpetual preferred stock, long-term preferred stock, certain perpetual preferred stock, hybrid capital instruments including mandatory convertible debt, term subordinated debt, intermediate-term preferred stock (original average maturity of at least five years), and net unrealized holding gains on equity securities (subject to certain limitations); provided, however, the amount of term subordinated debt and intermediate term preferred stock that may be included in Tier 2 capital for risk-based capital purposes is limited to 50% of Tier 1 capital.
	The FDIC currently measures an institution’s capital using a leverage limit together with certain risk-based ratios.  The FDIC’s minimum leverage capital requirement specifies a minimum ratio of Tier 1 capital to average total assets.  Most banks are required to maintain a minimum leverage ratio of at least 3% to 4% of total assets.  The FDIC retains the right to require a particular institution to maintain a higher capital level based on an institution’s particular risk profile.
	FDIC regulations also establish a measure of capital adequacy based on ratios of qualifying capital to risk-weighted assets.  Assets are placed in one of four categories and given a percentage weight—0%, 20%, 50% or 100%—based on the relative risk of the category.  In addition, certain off-balance-sheet items are converted to balance-sheet credit equivalent amounts, and each amount is then assigned to one of the four categories.  Under the guidelines, the ratio of total capital (Tier 1 capital plus Tier 2 capital) to risk-weighted assets must be at least 8%, and the ratio of Tier 1 capital to risk-weighted assets must be at least 4%.  In evaluating the adequacy of a bank’s capital, the FDIC may also consider other factors that may affect the bank’s financial condition.  Such factors may include interest rate risk exposure, liquidity, funding and market risks, the quality and level of earnings, concentration of credit risk, risks arising from nontraditional activities, loan and investment quality, the effectiveness of loan and investment policies, and management’s ability to monitor and control financial operating risks.
	FDIC capital requirements are designated as the minimum acceptable standards for banks whose overall financial condition is fundamentally sound, which are well-managed and have no material or significant financial weaknesses.  The FDIC capital regulations state that, where the FDIC determines that the financial history or condition, including off-balance-sheet risk, managerial resources and/or the future earnings prospects of a bank are not adequate and/or a bank has a significant volume of assets classified substandard, doubtful or loss or otherwise criticized, the FDIC may determine that the minimum adequate amount of capital for the bank is greater than the minimum standards established in the regulation.
	The following table shows the regulatory capital ratios of the Company and the Banks and the minimum regulatory requirements (dollars in thousands):
		Actual				Minimum for Capital Adequacy Purposes				Minimum to be Categorized as “Well-Capitalized” Under Prompt Corrective Action Provisions
		Amount		Ratio		Amount		Ratio		Amount		Ratio
	December 31, 2014:
	The Company—consolidated:
	Total capital to risk-weighted assets	$	684,583	16.8	%	$	326,071	8	%	n/a		n/a
	Tier 1 capital to risk-weighted assets	633,317		15.54		163,036		4		n/a		n/a
	Tier 1 leverage capital to average assets	633,317		13.41		188,885		4		n/a		n/a
	Banner Bank:
	Total capital to risk- weighted assets	605,997		15.53		312,220		8		$	390,274	10	%
	Tier 1 capital to risk- weighted assets	556,897		14.27		156,110		4		234,165		6
	Tier 1 leverage capital to average assets	556,897		12.42		179,304		4		224,130		5
	Islanders Bank:
	Total capital to risk- weighted assets	36,590		19.92		14,693		8		18,367		10
	Tier 1 capital to risk- weighted assets	34,332		18.69		7,347		4		11,020		6
	Tier 1 leverage capital to average assets	34,332		13.68		10,040		4		12,550		5
	December 31, 2013:
	The Company—consolidated:
	Total capital to risk-weighted assets	$	631,674	16.99	%	$	297,493	8	%	n/a		n/a
	Tier 1 capital to risk-weighted assets	584,838		15.73		148,747		4		n/a		n/a
	Tier 1 leverage capital to average assets	584,838		13.64		171,553		4		n/a		n/a
	Banner Bank:
	Total capital to risk- weighted assets	557,253		15.75		282,984		8		$	353,730	10	%
	Tier 1 capital to risk- weighted assets	512,689		14.49		141,192		4		212,238		6
	Tier 1 leverage capital to average assets	512,689		12.65		162,174		4		202,707		5
	Islanders Bank:
	Total capital to risk- weighted assets	34,795		18.73		14,859		8		18,574		10
	Tier 1 capital to risk- weighted assets	32,469		17.48		7,430		4		11,144		6
	Tier 1 leverage capital to average assets	32,469		13.6		9,553		4		11,941		5
	At December 31, 2014, Banner Corporation and the Banks each exceeded all regulatory capital adequacy requirements.  There have been no conditions or events since December 31, 2014 that have materially adversely changed the Tier 1 or Tier 2 capital of the Company or the Banks.  However, events beyond the control of the Banks, such as weak or depressed economic conditions in areas where the Banks have most of their loans, could adversely affect future earnings and, consequently, the ability of the Banks to meet their respective capital requirements.  The Company may not declare or pay cash dividends on, or repurchase, any of its shares of common stock if the effect thereof would cause equity to be reduced below applicable regulatory capital maintenance requirements or if such declaration and payment would otherwise violate regulatory requirements.
	On July 2, 2013, the Federal Reserve approved a final rule (Final Rule) to establish a new comprehensive regulatory capital framework for all U.S. financial institutions and their holding companies. On July 9, 2013, the Final Rule was approved as an interim final rule by the FDIC. The Final Rule implements the “Basel III” regulatory capital reforms and changes required by the Dodd-Frank Act. The final rule includes new risk-based capital and leverage ratios, which are effective January 1, 2015 and revise the definition of what constitutes “capital” for purposes of calculating those ratios.
	Effective January 1, 2015 (with some changes transitioned into full effectiveness over two to four years), Banner and the Banks became subject to the new capital requirements adopted by the Federal Reserve and the FDIC. These new requirements create a new required ratio for common equity Tier 1 (“CET1”) capital, increase the leverage and Tier 1 capital ratios, change the risk-weights of certain assets for purposes of the risk-based capital ratios, create an additional capital conservation buffer over the required capital ratios and change what qualifies as capital for purposes of meeting these various capital requirements. Beginning in 2016, failure to maintain the required capital conservation buffer will limit our ability and the ability of our bank subsidiary to pay dividends, repurchase shares or pay discretionary bonuses. Under the new capital regulations, the minimum capital ratios applicable to Banner and the Banks are: (i) a CETI capital ratio of 4.5%; (ii) a Tier 1 capital ratio of 6% (increased from 4%); (iii) a total capital ratio of 8% (unchanged from prior rules); and (iv) a Tier 1 leverage ratio of 4% for all institutions. CET1 generally consists of common stock; retained earnings; accumulated other comprehensive income (“AOCI”), explained below, unless we elect to exclude AOCI from regulatory capital, as discussed below; and certain minority interests; all subject to applicable regulatory adjustments and deductions. There are a number of changes in what constitutes regulatory capital, some of which are subject to transition periods. These changes include the phasing-out of certain instruments as qualifying capital. Banner and the Banks do not have any of these instruments. Under the new requirements for total capital, Tier 2 capital is no longer limited to the amount of Tier 1 capital included in total capital. Mortgage servicing rights, certain deferred tax assets and investments in unconsolidated subsidiaries over designated percentages of CET1 will be deducted from capital. In addition, Tier 1 capital will include AOCI, which includes all unrealized gains and losses on available for sale debt and equity securities. Because of our asset size, we have the one-time option of deciding in the first quarter of 2015 whether to permanently opt-out of the inclusion of accumulated other comprehensive income in our capital calculations. We are planning to take advantage of this opt-out to reduce the impact of market volatility on our regulatory capital levels.
	The new requirements also include changes in the risk-weights of assets to better reflect credit risk and other risk exposures. These include a 150% risk weight (up from 100%) for certain high volatility commercial real estate acquisition, development and construction loans and for non-residential mortgage loans that are 90 days past due or otherwise in non-accrual status; a 20% (up from 0%) credit conversion factor for the unused portion of a commitment with an original maturity of one year or less that is not unconditionally cancellable (currently set at 0%); a 250% risk weight (up from 100%) for mortgage servicing and deferred tax assets that are not deducted from capital; and increased risk-weights (0% to 600%) for equity exposures.
	In addition to the minimum CET1, Tier 1 and total capital ratios, Banner and the Banks will have to maintain a capital conservation buffer consisting of additional CET1 capital greater than 2.5% of risk-weighted assets above the required minimum levels in order to avoid limitations on paying dividends, engaging in share repurchases, and paying discretionary bonuses based on percentages of eligible retained income that could be utilized for such actions. This new capital conservation buffer requirement will be phased in beginning in January 2016 at 0.625% of risk-weighted assets and increasing each year until fully implemented in January 2019.

CONTINGENCIES

CONTINGENCIES	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
CONTINGENCIES	CONTINGENCIES
	In the normal course of business, the Company and/or its subsidiaries have various legal proceedings and other contingent matters outstanding.  These proceedings and the associated legal claims are often contested and the outcome of individual matters is not always predictable.  These claims and counter-claims typically arise during the course of collection efforts on problem loans or with respect to action to enforce liens on properties in which the Banks hold a security interest.  Based upon the information known to management at this time, the Company and the Banks are not a party to any legal proceedings that management believes would have a material adverse effect on the results of operations or consolidated financial position at December 31, 2014.
	In connection with certain asset sales, the Banks typically make representations and warranties about the underlying assets conforming to specified guidelines.  If the underlying assets do not conform to the specifications, the Bank may have an obligation to repurchase the assets or indemnify the purchaser against any loss.  The Banks believe that the potential for material loss under these arrangements is remote.  Accordingly, the fair value of such obligations is not material.
	In February 2009, for the first time in its history, the State of Washington’s Public Deposit Protection Commission assessed all Qualified Public Depositories participating in the State’s public deposit program an amount that, in aggregate, covered the uninsured portion of the public funds on deposit at a failed Washington bank.  Generally, the maximum liability should any member(s) of the State’s public deposit program default on its uninsured public funds is limited to 10% of the public funds held by the Banks.  A similar program is also in place in Oregon, where Banner Bank also holds public deposits.  Should other bank failures occur in either state, the Banks could be subject to additional assessments; however, the rules for participation have been revised to require 100% collateralization of these deposits in the State of Washington and a range of 50% to 110% in the State of Oregon, depending of an institution's CAMEL rating, which serves to significantly limit the contingent liability that currently exists for Qualified Public Depositories.  As a result of these collateralization requirements, the Banks have generally sought to reduce their reliance on public funds since February 2009. Public funds totaled $138 million at December 31, 2014 as compared to $139 million at December 31, 2013.

INTEREST_RATE_RISK

INTEREST RATE RISK	12 Months Ended
	Dec. 31, 2014
Interest Rate Derivatives [Abstract]
INTEREST RATE RISK	INTEREST RATE RISK
	The financial condition and operation of the Company are influenced significantly by general economic conditions, including the absolute level of interest rates as well as changes in interest rates and the slope of the yield curve.  The Company’s profitability is dependent to a large extent on its net interest income, which is the difference between the interest received from its interest-earning assets and the interest expense incurred on its interest-bearing liabilities.
	The activities of the Company, like all financial institutions, inherently involve the assumption of interest rate risk.  Interest rate risk is the risk that changes in market interest rates will have an adverse effect on the institution’s earnings and underlying economic value.  Interest rate risk is determined by the maturity and repricing characteristics of an institution’s assets, liabilities and off-balance-sheet contracts.  Interest rate risk is measured by the variability of financial performance and economic value resulting from changes in interest rates.  Interest rate risk is the primary market risk impacting the Company’s financial performance.
	The greatest source of interest rate risk to the Company results from the mismatch of maturities or repricing intervals for rate-sensitive assets, liabilities and off-balance-sheet contracts.  Additional interest rate risk results from mismatched repricing indices and formula (basis risk and yield curve risk), product caps and floors, and early repayment or withdrawal provisions (option risk), which may be contractual or market driven, that are generally more favorable to customers than to the Company.
	The Company’s primary monitoring tool for assessing interest rate risk is asset/liability simulation modeling, which is designed to capture the dynamics of balance sheet, interest rate and spread movements, and to quantify variations in net interest income and economic value of equity resulting from those movements under different rate environments.  Another monitoring tool used by the Company to assess interest rate risk is gap analysis.  The matching of repricing characteristics of assets and liabilities may be analyzed by examining the extent to which such assets and liabilities are interest sensitive and by monitoring the Company’s interest sensitivity gap.  Management is aware of the sources of interest rate risk and in its opinion actively monitors and manages it to the extent possible, and considers that the Company’s current level of interest rate risk is reasonable.

OTHER_INTANGIBLE_ASSETS_AND_MO

OTHER INTANGIBLE ASSETS AND MORTGAGE SERVICING RIGHTS	12 Months Ended
	Dec. 31, 2014
Other Intangible Assets and Mortgage Servicing Rights [Abstract]
OTHER INTANGIBLE ASSETS AND MORTGAGE SERVICING RIGHTS	INTANGIBLE ASSETS AND MORTGAGE SERVICING RIGHTS
	Intangible Assets: At December 31, 2014, intangible assets consisted primarily of core deposit intangibles (CDI), which are amounts recorded in business combinations or deposit purchase transactions related to the value of transaction-related deposits and the value of the customer relationships associated with the deposits.
	The Company amortizes CDI over its estimated useful life and reviews it at least annually for events or circumstances that could impair its value.  The CDI assets shown in the table below represent the value ascribed to the long-term deposit relationships acquired in three separate bank acquisitions during 2007, a single branch acquisition in 2013, and the Branch Acquisition in 2014.  These intangible assets are being amortized using an accelerated method over estimated useful lives of three to eight years.  The CDI assets are not estimated to have a significant residual value.  Other intangible assets are amortized over their estimated useful lives and are also reviewed for impairment.
	The following table summarizes the changes in the Company’s CDI and other intangibles for the years ended December 31, 2012, 2013 and 2014 (in thousands):
		CDI			Other			Total
	Balance, December 31, 2011	$	6,322		$	9		$	6,331
	Amortization	(2,092		)	(9		)	(2,101		)
	Balance, December 31, 2012	4,230			—			4,230
	Additions through acquisition	160			—			160
	Amortization	(1,941		)	—			(1,941		)
	Balance, December 31, 2013	2,449			—			2,449
	Additions through acquisition	2,372			—			2,372
	Amortization	(1,990		)	—			(1,990		)
	Balance, December 31, 2014	$	2,831		$	—		$	2,831
	Estimated amortization expense in future years with respect to existing intangibles as of December 31, 2014 (in thousands):
	Year Ended:	CDI
	December 31, 2015	$	1,007
	December 31, 2016	353
	December 31, 2017	321
	December 31, 2018	296
	Thereafter	854
	Net carrying amount	$	2,831
	Mortgage servicing rights are reported in other assets.  Mortgage servicing rights are initially reported at fair value and are amortized in proportion to, and over the period of, the estimated future net servicing income of the underlying financial assets.  Mortgage servicing rights are subsequently evaluated for impairment based upon the fair value of the rights compared to the amortized cost (remaining unamortized initial fair value).  If the fair value is less than the amortized cost, a valuation allowance is created through an impairment charge to servicing fee income.  However, if the fair value is greater than the amortized cost, the amount above the amortized cost is not recognized in the carrying value.  In 2014, the Company did not record any impairment charges or recoveries against mortgage servicing rights. In 2013, the Company recorded a recovery of $1.3 million in previously recognized impairment charges against mortgage servicing rights. In 2012, the Company recorded $400,000 in impairment charges against mortgage servicing rights.  Loans serviced for others totaled $1.391 billion and $1.216 billion at December 31, 2014 and 2013, respectively.  Custodial accounts maintained in connection with this servicing totaled $6.7 million and $5.7 million at December 31, 2014 and 2013, respectively.
	An analysis of the mortgage servicing rights for the years ended December 31, 2014, 2013 and 2012 is presented below (in thousands):
		Years Ended December 31
		2014			2013			2012
	Balance, beginning of the year	$	8,086		$	6,244		$	5,584
	Amounts capitalized	3,023			2,913			3,662
	Amortization (1)	(2,079		)	(2,371		)	(2,602		)
	Valuation adjustments in the period	—			1,300			(400		)
	Balance, end of the year (2)	$	9,030		$	8,086		$	6,244
	(1)	Amortization of mortgage servicing rights is recorded as a reduction of loan servicing income and any unamortized balance is fully written off if the loan repays in full.
	(2)	Balances as of December 31, 2014 and 2013 are net of no valuation allowances, and as of December 31, 2012 are net of a $1.3 million valuation allowance.

FAIR_VALUE_OF_FINANCIAL_INSTRU

FAIR VALUE OF FINANCIAL INSTRUMENTS	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
FAIR VALUE OF FINANCIAL INSTRUMENTS	FAIR VALUE OF FINANCIAL INSTRUMENTS
	The Company has elected to record certain assets and liabilities at fair value. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (that is, not a forced liquidation or distressed sale). GAAP (ASC 820, Fair Value Measurements) establishes a consistent framework for measuring fair value and disclosure requirements about fair value measurements. Among other things, the standard requires us to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect the Company’s estimates for market assumptions. These two types of inputs create the following fair value hierarchy:
	•	Level 1 – Quoted prices in active markets for identical instruments. An active market is a market in which transactions occur with sufficient frequency and volume to provide pricing information on an ongoing basis. A quoted price in an active market provides the most reliable evidence of fair value and shall be used to measure fair value whenever available.
	•	Level 2 – Observable inputs other than Level 1 including quoted prices in active markets for similar instruments, quoted prices in less active markets for identical or similar instruments, or other observable inputs that can be corroborated by observable market data. Our use of Level 2 measurements for these securities is generally based upon a matrix pricing model from an investment reporting and valuation service. Matrix pricing is a mathematical technique used principally to value debt securities without relying exclusively on quoted prices for the specific securities, but rather by relying on the securities’ relationship to other benchmark quoted securities.
	•	Level 3 – Unobservable inputs supported by little or no market activity for financial instruments whose value is determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation; also includes observable inputs from non-binding single dealer quotes not corroborated by observable market data. In developing Level 3 measurements, management incorporates whatever market data might be available and uses discounted cash flow models where appropriate. These calculations include projections of future cash flows, including appropriate default and loss assumptions, and market based discount rates.
	The estimated fair value amounts of financial instruments have been determined by the Company using available market information and appropriate valuation methodologies.  However, considerable judgment is required to interpret data to develop the estimates of fair value.  Accordingly, the estimates presented herein are not necessarily indicative of the amounts the Company could realize in a current market exchange.  The use of different market assumptions and/or estimation methodologies may have a material effect on the estimated fair value amounts.  In addition, reasonable comparability between financial institutions may not be likely due to the wide range of permitted valuation techniques and numerous estimates that must be made given the absence of active secondary markets for many of the financial instruments.  This lack of uniform valuation methodologies also introduces a greater degree of subjectivity to these estimated fair values. Transfers between levels of the fair value hierarchy are deemed to occur at the end of the reporting period.
	Items Measured at Fair Value on a Recurring Basis
	Banner records trading account securities, securities available-for-sale, FHLB advances, junior subordinated debentures and certain derivative transactions at fair value on a recurring basis.
	•	Investment securities primarily consist of U.S. Government and agency obligations, municipal bonds, corporate bonds, single issue trust preferred securities (TPS), pooled trust preferred collateralized debt obligation securities (TRUP CDO), mortgage-backed securities, asset-backed securities, equity securities and certain other financial instruments.
	From mid-2008 through the current year, the lack of active markets and market participants for certain securities resulted in an increase in Level 3 measurements. In particular, the market for our TRUP CDO securities has been generally inactive during this period. This was evidenced first by a significant widening of the bid-ask spread in the brokered markets in which TRUP CDOs trade and then by a significant decrease in the volume of trades relative to historical levels. The new issue market is also inactive as almost no new TRUP CDOs have been issued since 2007. There are still very few market participants who are willing and/or able to transact for these securities. Thus, a low market price for a particular bond may only provide evidence of lack of an active market rather than being an indicator of credit problems with a particular issuer or of the fair value of the security. As of December 31, 2014, Banner owned $10 million in current par value of these securities.
	Given these conditions and the absence of observable transactions in the secondary and new issue markets, management determined that for the TRUP CDOs at December 31, 2014 and 2013:
	•	The few observable transactions and market quotations that were available were not reliable for purposes of determining fair value,
	•	An income valuation approach technique (present value technique) that maximizes the use of relevant observable inputs and minimizes the use of unobservable inputs was equally or more representative of fair value than the market approach valuation technique, and
	•	The Company’s TRUP CDOs should be classified exclusively within Level 3 of the fair value hierarchy because of the significant assumptions required to determine fair value at the measurement date.
	The TRUP CDO valuations were derived using input from independent third parties who used proprietary cash flow models for analyzing collateralized debt obligations.  Their approaches to determining fair value involve considering the credit quality of the collateral, assuming a level of defaults based on the probability of default of each underlying trust preferred security, creating expected cash flows for each TRUP CDO security and discounting that cash flow at an appropriate risk-adjusted rate plus a liquidity premium.
	Where appropriate, management reviewed the valuation methodologies, and assumptions used by the independent third party providers and for certain securities determined that the fair value estimates were reasonable and utilized those estimates in the Company’s reported financial statements, while for other securities management adjusted the third party providers modeling to be more reflective of the characteristics of the Company’s remaining TRUP CDOs. Further, during the year ended December 31, 2014, two of our TRUP CDOs, which had previously incurred significant fair value write downs, were repaid in full, resulting in equally significant fair value gains on those securities in 2014. The net result of the fair value analysis of these Level 3 measurements was a fair value gain of $4.9 million for the year-ended December 31, 2014, primarily a result of repayment of the two securities noted above, compared to a $255,000 fair value loss in the year ended December 31, 2013 and a $3.3 million gain in the year ended December 31, 2012. The small loss in the year ending December 31, 2013, was primarily the result of a modest adjustment to the discount rate which more than offset the impact of the passage of time on the years to maturity in the discounted present value calculation used to estimate the fair value of these securities. In management's opinion the small valuation change was consistent with general market stability for credit spreads supported by other market observations. The more significant gain in the year ended December 31, 2012, was primarily caused by a reduction in the spread between the benchmark credit equivalent indices used to establish an appropriate discount rate and a similar maturity point on the interest rate swap curve, which resulted in a more substantial adjustment to the discount rate.
	At December 31, 2014, Banner also directly owned approximately $19 million in amortized cost of single issuer TPS securities for which no market data or independent valuation source is available. Similar to the TRUP CDOs above, there were too few, if any, issuances of new TPS securities or sales of existing TPS securities to provide Level 1 or even Level 2 fair value measurements for these securities. Management, therefore, utilized a discounted cash-flow model to calculate the present value of each security’s expected future cash flows to determine their respective fair values. Management took into consideration the limited market data that was available regarding similar securities and assessed the performance of the three individual issuers of TPS securities owned by the Company. At December 31, 2014, the Company again sought input from independent third parties to help it establish an appropriate set of parameters to identify a reasonable range of discount rates for use in its fair value model. Management concluded that market yields have been reasonably stable in recent periods but that the indicated spreads and implied yields for non-investment grade securities as well as the yields associated with individual issuers in the third party analyst reports suggested that a 500 basis point spread over the three-month LIBOR index, 25 basis points less than the spread as used a year earlier, was a reasonable basis for determining an appropriate discount rate to estimate the fair value of these securities. These factors were then incorporated into the model at December 31, 2014, where a discount rate equal to three-month LIBOR plus 500 basis points was used to calculate the respective fair values of these securities The result of this Level 3 fair value measurement was a fair value gain of $35,000 in the year ended December 31, 2014, compared to a gain of $74,000 in the year ended December 31, 2013 and a gain of $578,000 in the year ended December 31, 2012. The much larger valuation change in 2012 was the result of decreasing the spreads to 525 basis points from a range of 600–800 used in 2011. The Company has and will continue to assess the appropriate fair value hierarchy for determination of these fair values on a quarterly basis.
	For trading securities other than TRUP CDOs and single-issuer TPS securities and for securities—available-for-sale we used matrix pricing models from investment reporting and valuation services. Management considers this to be a Level 2 input method.
	•	Fair valuations for FHLB advances are estimated using fair market values provided by the lender, the FHLB of Seattle.  The FHLB of Seattle prices advances by discounting the future contractual cash flows for individual advances using its current cost of funds curve to provide the discount rate.  Management considers this to be a Level 2 input method.
	•	The fair valuations of junior subordinated debentures (TPS-related debt that the Company has issued) were also valued using discounted cash flows. These debentures carry interest rates that reset quarterly, using the three-month LIBOR index plus spreads of 1.38% to 3.35%. While the quarterly reset of the index on this debt would seemingly keep its fair value reasonably close to book values, the disparity in the fixed spreads above the index and the inability to determine realistic current market spreads, due to lack of new issuances and trades, resulted in having to rely more heavily on assumptions about what spread would be appropriate if market transactions were to take place. In periods prior to the third quarter of 2008, the discount rate used was based on recent issuances or quotes from brokers on the date of valuation for comparable bank holding companies and was considered to be a Level 2 input method. However, as noted above in the discussion of TPS and TRUP CDOs, due to the unprecedented disruption of certain financial markets, management concluded that there were insufficient transactions or other indicators to continue to reflect these measurements as Level 2 inputs. Due to this reliance on assumptions and not on directly observable transactions, management believes fair value for these instruments should follow a Level 3 input methodology. Since the discount rate used in the fair value modeling is the most sensitive unobservable estimate in the calculation, the Company again utilized input from the same independent third party noted above to help it establish an appropriate set of parameters to identify a reasonable range of discount rates for use in its fair value model. In valuing the debentures at June 30, 2012, these changes in credit quality were the primary factor contributing to a reduction in the discount rate from 800 basis points to 550 basis points. In further valuing the debentures at September 30, 2012, management evaluated the general market tightening of credit spreads as noted above and reduced the discount rate to the period-ending three-month LIBOR plus 525 basis points. This spread of 525 basis points to LIBOR was used to establish discount rates and fair value estimates at December 31, 2012 and 2013. As noted above in the discussion about single-issuer TPS securities, since market spreads have been reasonably stable in recent periods; however, we further reduced the spread to 500 basis points at December 31, 2014, resulting in a fair value loss on these instruments of $4.1 million for the year ended December 31, 2014, compared to a $865,000 loss in the year ended December 31, 2013 and a $23.1 million loss in the year ended December 31, 2012. The fair value adjustment in the current year was primarily the result of the passage of time on the years to maturity in the discounted present value calculation used to estimate the fair value.
	•	Derivative instruments include interest rate commitments related to one- to four family loans and residential mortgage backed securities and interest rate swaps. The fair value of interest rate lock commitments and forward sales commitments are estimated using quoted or published market prices for similar instruments, adjusted for factors such as pull-through rate assumptions based on historical trends, where appropriate. The fair value of interest rate swaps is determined by using current market quotes on similar instruments provided by active broker/dealers in the swap market. Management considers these to be Level 2 input methods. The changes in the fair value of all these derivative instruments are primarily attributable to changes in the level of market interest rates. The Company has elected to record the fair value of these derivative instruments on a net basis.
	The following tables present financial assets and liabilities measured at fair value on a recurring basis and the level within the fair value hierarchy of the fair value measurements for those assets and liabilities as of December 31, 2014 and 2013 (in thousands):
		December 31, 2014
		Level 1				Level 2			Level 3		Total
	Assets:
	Securities—available-for-sale
	U.S. Government and agency	$	—			$	29,770		$	—	$	29,770
	Municipal bonds	—				50,028			—		50,028
	Corporate bonds	—				5,018			—		5,018
	Mortgage-backed securities	—				300,810			—		300,810
	Asset-backed securities	—				25,395			—		25,395
		—				411,021			—		411,021
	Securities—trading
	U.S. Government and agency	—				1,505			—		1,505
	Municipal bonds	—				1,440			—		1,440
	TPS and TRUP CDOs	—				—			19,118		19,118
	Mortgage-backed securities	—				18,136			—		18,136
	Equity securities and other	—				59			—		59
		—				21,140			19,118		40,258
	Derivatives
	Interest rate lock commitments	—				—			317		317
	Interest rate swaps	—				6,290			—		6,290
		$	—			$	438,451		$	19,435	$	457,886
	Liabilities
	Advances from FHLB at fair value	$	—			$	32,250		$	—	$	32,250
	Junior subordinated debentures net of unamortized deferred issuance costs at fair value	—				—			78,001		78,001
	Derivatives
	Interest rate forward sales commitments	—				198			—		198
	Interest rate swaps	—				6,290			—		6,290
		$	—			$	38,738		$	78,001	$	116,739
		December 31, 2013
		Level 1				Level 2			Level 3		Total
	Assets:
	Securities—available-for-sale
	U.S. Government and agency	$	—			$	58,660		$	—	$	58,660
	Municipal bonds	—				52,855			—		52,855
	Corporate bonds	—				6,964			—		6,964
	Mortgage-backed securities	—				326,610			—		326,610
	Asset-backed securities	—				25,191			—		25,191
		—				470,280			—		470,280
	Securities—trading
	U.S. Government and agency	—				1,481			—		1,481
	Municipal bonds	—				5,023			—		5,023
	TPS and TRUP CDOs	—				—			35,140		35,140
Mortgage-backed securities	—				20,760			—		20,760
Equity securities and other	—				68			—		68
	—				27,332			35,140		62,472
Derivatives
Interest rate lock commitments	—				—			130		130
Interest rate swaps	—				4,946			—		4,946
	$	—			$	502,558		$	35,270	$	537,828
Liabilities
Advances from FHLB at fair value	$	—			$	27,250		$	—	$	27,250
Junior subordinated debentures net of unamortized deferred issuance costs at fair value	—				—			73,928		73,928
Derivatives
Interest rate forward sales commitments	—				43			—		43
Interest rate swaps	—				4,946			—		4,946
	$	—			$	32,239		$	73,928	$	106,167
The following table provides a reconciliation of the assets and liabilities measured at fair value using significant unobservable inputs (Level 3) on a recurring basis during the year ended December 31, 2014 and 2013 (in thousands):
	Year Ended December 31, 2014
	Level 3 Fair Value Inputs
	TPS and TRUP				Borrowings—
	CDOs				Junior Subordinated
					Debentures
Beginning balance at December 31, 2013	$	35,140			$	73,928
Total gains or losses recognized
Assets gains (losses)	5,481				—
Liabilities (gains) losses	—				4,073
Purchases, issuances and settlements	—				—
Paydowns and maturities	(21,502		)		—
Transfers in and/or out of Level 3	—				—
Ending balance at December 31, 2014	$	19,119			$	78,001
	Year Ended December 31, 2013
	Level 3 Fair Value Inputs
	TPS and TRUP				Borrowings—
	CDOs				Junior Subordinated
					Debentures
Beginning balance at December 31, 2012	$	35,741			$	73,063
Total gains or losses recognized
Assets gains (losses)	(181		)		—
Liabilities (gains) losses	—				865
Purchases, issuances and settlements	—				—
Paydowns and maturities	(420		)		—
Transfers in and/or out of Level 3	—				—
Ending balance at December 31, 2013	$	35,140			$	73,928
The Company has elected to continue to recognize the interest income and dividends from the securities reclassified to fair value as a component of interest income as was done in prior years when they were classified as available-for-sale.  Interest expense related to the FHLB advances and junior subordinated debentures continues to be measured based on contractual interest rates and reported in interest expense.  The change in fair value of these financial instruments has been recorded as a component of other operating income.
Items Measured at Fair Value on a Non-recurring Basis
Carrying values of certain impaired loans are periodically evaluated to determine if valuation adjustments, or partial write-downs, should be recorded. These non-recurring fair value adjustments are recorded when observable market prices or current appraised values of collateral indicate a shortfall in collateral value or discounted cash flows indicate a shortfall compared to current carrying values of the related loan. If the Company determines that the value of the impaired loan is less than the carrying value of the loan, the Company either establishes an impairment reserve as a specific component of the allowance for loan and lease losses (ALLL) or charges off the impaired amount. The remaining impaired loans are evaluated for reserve needs in homogenous pools within the Company’s ALLL methodology. As of December 31, 2014, the Company reviewed all of its adversely classified loans totaling $64 million and identified $46 million which were considered impaired. Of those $46 million in impaired loans, $34 million were individually evaluated to determine if valuation adjustments, or partial write-downs, should be recorded, or if specific impairment reserves should be established. The $34 million had original carrying values of $37 million which have been reduced by partial write-downs totaling $3 million. In addition to these write-downs, in order to bring the impaired loan balances to fair value, Banner also established $3 million in specific reserves on these impaired loans. Impaired loans that were collectively evaluated for reserve purposes within homogenous pools totaled $11 million and were found to require allowances totaling $126,000. The valuation inputs for impaired loans are considered to be Level 3 inputs.
The Company records REO (acquired through a lending relationship) at fair value on a non-recurring basis. All REO properties are recorded at the lower of the estimated fair value of the properties, less expected selling costs, or the carrying amount of the defaulted loans. From time to time, non-recurring fair value adjustments to REO are recorded to reflect partial write-downs based on an observable market price or current appraised value of property. Banner considers any valuation inputs related to REO to be Level 3 inputs. The individual carrying values of these assets are reviewed for impairment at least annually and any additional impairment charges are expensed to operations. For the years ended December 31, 2014 and 2013, the Company recognized $37,000 and $785,000, respectively of impairment charges related to these types of assets.
Mortgage servicing rights are reported in other assets. Mortgage servicing rights are initially reported at fair value and are amortized in proportion to, and over the period of, the estimated future net servicing income of the underlying financial assets. Mortgage servicing rights are subsequently evaluated for impairment based upon the fair value of the rights compared to the amortized cost (remaining unamortized initial fair value). If the fair value is less than the amortized cost, a valuation allowance is created through an impairment charge to servicing fee income. However, if the fair value is greater than the amortized cost, the amount above the amortized cost is not recognized in the carrying value. In 2014, the Company did not record any impairment charges against mortgage servicing rights. In 2013, the Company reversed $1.3 million in previously recorded impairment charges against mortgage servicing rights.
The following tables present financial assets and liabilities measured at fair value on a non-recurring basis and the level within the fair value hierarchy at December 31, 2014 and 2013 (in thousands):
	At or For the Year Ended December 31, 2014
	Level 1				Level 2			Level 3		Total		Net Losses Recognized During the Period
Impaired loans	$	—			$	—		$	4,725	$	4,725	$	(512	)
REO	—				—			3,352		3,352		(453		)
	At or For the Year Ended December 31, 2013
	Level 1				Level 2			Level 3		Total		Net Losses Recognized During the Period
Impaired loans	$	—			$	—		$	10,627	$	10,627	$	(4,890	)
REO	—				—			4,044		4,044		(853		)
Assets and Liabilities Measured at Fair Value Using Significant Unobservable Inputs (Level 3)
The following table provides a description of the valuation technique, unobservable inputs, and qualitative information about the unobservable inputs for the Company's assets and liabilities classified as Level 3 and measured at fair value on a recurring and nonrecurring basis at December 31, 2014 and 2013:
						31-Dec
						2014		2013
Financial Instruments		Valuation Technique		Unobservable Inputs		Weighted Average Rate		Weighted Average Rate
TPS securities		Discounted cash flows		Discount rate		5.26	%	5.5	%
TRUP CDOs		Discounted cash flows		Discount rate		3.96		3.85
Junior subordinated debentures		Discounted cash flows		Discount rate		5.26		5.5
Impaired loans		Discounted cash flows		Discount rate		Various		Various
		Collateral Valuations		Market values		n/a		n/a
REO		Appraisals		Market values		n/a		n/a
TPS and TRUP CDOs: Management believes that the credit risk-adjusted spread used to develop the discount rate utilized in the fair value measurement of TPS and TRUP CDOs is indicative of the risk premium a willing market participant would require under current market conditions for instruments with similar contractual rates and terms and conditions and issuers with similar credit risk profiles and with similar expected probability of default. Management attributes the change in fair value of these instruments, compared to their par value, primarily to perceived general market adjustments to the risk premiums for these types of assets subsequent to their issuance.
Junior subordinated debentures: Similar to the TPS and TRUP CDOs discussed above, management believes that the credit risk-adjusted spread utilized in the fair value measurement of the junior subordinated debentures is indicative of the risk premium a willing market participant would require under current market conditions for an issuer with Banner's credit risk profile. Management attributes the change in fair value of the junior subordinated debentures, compared to their par value, primarily to perceived general market adjustments to the risk premiums for these types of liabilities subsequent to their issuance. Future contractions in the risk adjusted spread relative to the spread currently utilized to measure the Company's junior subordinated debentures at fair value as of December 31, 2014, or the passage of time, will result in negative fair value adjustments. At December 31, 2014, the discount rate utilized was based on a credit spread of 500 basis points and three month LIBOR of 26 basis points.
Impaired loans: Loans are considered impaired when, based on current information and events; we determine that it is probable that we will be unable to collect all amounts due according to the contractual terms of the loan agreement. Factors involved in determining impairment include, but are not limited to, the financial condition of the borrower, the value of the underlying collateral and the current status of the economy. Impaired loans are measured based on the present value of expected future cash flows discounted at the loan's effective interest rate or, as a practical expedient, at the loan's observable market price or the fair value of collateral if the loan is collateral dependent. If this practical expedient is used, the impaired loans are considered to be held at fair value. Subsequent changes in the value of impaired loans are included within the provision for loan losses in the same manner in which impairment initially was recognized or as a reduction in the provision that would otherwise be reported.
REO: Fair value adjustments on REO are based on updated real estate appraisals, less selling costs,which are based on current market conditions.
MSRs: Management believes that the discount rate utilized in the fair valuation of our MSRs is indicative of a reasonable yield expectation in an orderly transaction between willing market participants at the measurement date. Generally, any significant increases in the prepayment rate and discount rate utilized in the fair value measurement of the mortgage servicing rights will result in negative fair value adjustments and a decrease in the fair value measurement. Alternatively, a decrease in the prepayment rate and discount rate will result in a positive fair value adjustment and increase in the fair value measurement. An increase in the weighted average life assumptions will result in a decrease in the prepayment rate and a decrease in the weighted average life will result in an increase of the prepayment rate.
Fair Values of Financial Instruments
The following table presents estimated fair values of the Company’s financial instruments as of December 31, 2014 and 2013, whether or not recognized or recorded in the consolidated Statements of Financial Condition.  The estimated fair value amounts have been determined by the Company using available market information and appropriate valuation methodologies.  However, considerable judgment is necessary to interpret market data in the development of the estimates of fair value.  Accordingly, the estimates presented herein are not necessarily indicative of the amounts the Company could realize in a current market exchange.  The use of different market assumptions and/or estimation methodologies may have a material effect on the estimated fair value amounts.  The carrying value and estimated fair value of financial instruments at December 31, 2014 and 2013 are as follows (in thousands):
	December 31, 2014							December 31, 2013
	Carrying				Estimated			Carrying		Estimated
	Value				Fair Value			Value		Fair Value
Assets:
Cash and due from banks	$	126,072			$	126,072		$	137,349	$	137,349
Securities—trading	40,258				40,258			62,472		62,472
Securities—available-for-sale	411,021				411,021			470,280		470,280
Securities—held-to-maturity	131,258				137,608			102,513		103,610
Loans receivable held for sale	2,786				2,807			2,734		2,751
Loans receivable	3,831,034				3,722,179			3,415,711		3,297,936
FHLB stock	27,036				27,036			35,390		35,390
BOLI	63,759				63,759			61,945		61,945
Mortgage servicing rights	9,030				12,987			8,086		11,529
Derivatives:
Interest rate swaps	6,290				6,290			4,946		4,946
Interest rate lock commitments	317				317			130		130
Liabilities:
Demand, interest-bearing checking and money market	2,227,292				1,998,649			1,946,467		1,697,095
Regular savings	901,142				784,006			798,764		695,863
Certificates of deposit	770,516				764,549			872,695		867,904
Advances from FHLB at fair value	32,250				32,250			27,250		27,250
Junior subordinated debentures at fair value	78,001				78,001			73,928		73,928
Other borrowings	77,185				77,185			83,056		83,056
Derivatives:
Interest rate swaps	6,290				6,290			4,946		4,946
Interest rate forward sales commitments	198				198			43		43
Fair value estimates, methods and assumptions and the level within the fair value hierarchy of the fair value measurements are set forth below for the Company’s financial and off-balance sheet instruments:
Cash and Due from Banks:  The carrying amount of these items is a reasonable estimate of their fair value. These fair values are considered Level 1 measures.
Securities:  The estimated fair values of investment securities and mortgaged-backed securities are priced using current active market quotes, if available, which are considered Level 1 measurements.  For most of the portfolio, matrix pricing based on the securities’ relationship to other benchmark quoted prices is used to establish the fair value.  These measurements are considered Level 2.  Due to continued credit concerns in the capital markets and inactivity in the trust preferred markets that have limited the observability of market spreads for some of the Company’s TPS and TRUP CDO securities (see earlier discussion above in determining the securities’ fair market value), management has classified these securities as a Level 3 fair value measure.
Loans Receivable Held for Sale: Carrying values are based on the lower of estimated fair values or book values. Fair values are estimated based on secondary market pricing for similar loans. This is considered a Level 2 fair value measure.
Loans Receivable: Fair values are estimated first by stratifying the portfolios of loans with similar financial characteristics.  Loans are segregated by type such as multifamily real estate, residential mortgage, nonresidential mortgage, commercial/agricultural, consumer and other.  Each loan category is further segmented into fixed- and adjustable-rate interest terms and by performing and non-performing categories. A preliminary estimate of fair value is then calculated based on discounted cash flows using as a discount rate the current rate offered on similar products, plus an adjustment for liquidity to reflect the non-homogeneous nature of the loans.  The preliminary estimate is then further reduced by the amount of the allowance for loan losses to arrive at a final estimate of fair value. Fair value for significant non-performing loans is based on recent appraisals or estimated cash flows discounted using rates commensurate with risk associated with the estimated cash flows.  Assumptions regarding credit risk, cash flows and discount rates are judgmentally determined using available market information and specific borrower information. Management considers this to be a Level 2 measurement.
FHLB Stock:  The fair value is based upon the redemption value of the stock which equates to its carrying value. This fair value is considered a Level 3 measure.
Bank-Owned Life Insurance: The fair value of BOLI policies owned are based on the various insurance contracts' cash surrender value. This fair value is considered a Level 1 measure.
Mortgage Servicing Rights: Fair values are estimated based on current pricing for sales of servicing for new loans adjusted up or down based on the serviced loan's interest rate versus current new loan rates. Management considers this to be a Level 3 measure.
Deposit Liabilities:  The fair value of deposits with no stated maturity, such as savings and checking accounts, is estimated by applying decay rate assumptions to segregated portfolios of similar deposit types to generate cash flows which are then discounted using short-term market interest rates.  The market value of certificates of deposit is based upon the discounted value of contractual cash flows.  The discount rate is determined using the rates currently offered on comparable instruments. Fair value estimates for deposits are considered Level 3 measures.
FHLB Advances and Other Borrowings:  Fair valuations for Banner’s FHLB advances are estimated using fair market values provided by the lender, the FHLB of Seattle.  The FHLB of Seattle prices advances by discounting the future contractual cash flows for individual advances using its current cost of funds curve to provide the discount rate.  This is considered to be a Level 2 input method.  Other borrowings are priced using discounted cash flows to the date of maturity based on using current rates at which such borrowings can currently be obtained. This fair value is considered a Level 3 measure.
Junior Subordinated Debentures:  Due to continued credit concerns in the capital markets and inactivity in the trust preferred markets that have limited the observability of market spreads (see earlier discussion above in determining the junior subordinated debentures’ fair market value), junior subordinated debentures have been classified as a Level 3 fair value measure.  Management believes that the credit risk adjusted spread and resulting discount rate utilized is indicative of those that would be used by market participants.
Derivative Instruments: Derivatives include interest rate swap agreements, interest rate lock commitments to originate loans held for sale and forward sales contracts to sell loans and securities related to mortgage banking activities. Fair values for the interest rate swaps which generally change as a result of changes in the level of market interest rates , are estimated based on dealer quotes and secondary market sources. Management considers these to be Level 2 inputs. The fair value of the interest rate lock commitments and forward sales commitments are estimated using quoted or published market prices for similar instruments, adjusted for factors such as pull-through rate assumptions where appropriate. The pull-through rate assumptions are considered Level 3 valuation inputs and are significant to the interest rate lock commitment valuation; as such, the interest rate lock commitment derivatives are classified as Level 3.
Limitations: The fair value estimates presented herein are based on pertinent information available to management as of December 31, 2014 and 2013.  Although management is not aware of any factors that would significantly affect the estimated fair value amounts, such amounts have not been comprehensively revalued for purposes of these financial statements since that date and, therefore, current estimates of fair value may differ significantly from the amounts presented herein.
Fair value estimates are based on existing on- and off-balance-sheet financial instruments without attempting to estimate the value of anticipated future business.  The fair value has not been estimated for assets and liabilities that are not considered financial instruments.  Significant assets and liabilities that are not financial instruments include the deferred tax assets/liabilities; land, buildings and equipment; costs in excess of net assets acquired; and real estate held for sale.

BANNER_CORPORATION_PARENT_COMP

BANNER CORPORATION (PARENT COMPANY ONLY)	12 Months Ended
	Dec. 31, 2014
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
BANNER CORPORATION (PARENT COMPANY ONLY)	BANNER CORPORATION (PARENT COMPANY ONLY)
	Summary financial information is as follows (in thousands):
	Statements of Financial Condition	31-Dec
		2014			2013
	ASSETS
	Cash	$	52,124		$	45,998
	Investment in trust equities	3,716			3,716
	Investment in subsidiaries	611,468			575,023
	Other assets	8,279			7,280
		$	675,587		$	632,017
	LIABILITIES AND STOCKHOLDERS’ EQUITY
	Miscellaneous liabilities	$	2,446		$	6,157
	Deferred tax liability	11,516			12,960
	Junior subordinated debentures at fair value	78,001			73,928
	Stockholders’ equity	583,624			538,972
		$	675,587		$	632,017
	Statements of Operations	Years Ended December 31
		2014			2013			2012
	INTEREST INCOME:
	Interest-bearing deposits	$	96		$	82		$	218
	OTHER INCOME (EXPENSE):
	Dividend income from subsidiaries	26,027			24,725			61,329
	Equity in undistributed income of subsidiaries	33,707			23,994			23,507
	Other income	67			3,016			55
	Net change in valuation of financial instruments carried at fair value	(4,073		)	(865		)	(23,075		)
	Interest on other borrowings	(2,914		)	(2,968		)	(3,395		)
	Other expenses	(2,519		)	(2,794		)	(2,375		)
	Net income before taxes	50,391			45,190			56,264
	BENEFIT FROM INCOME TAXES	(3,774		)	(1,365		)	(8,618		)
	NET INCOME	54,165			46,555			64,882
	PREFERRED STOCK DIVIDEND AND DISCOUNT ACCRETION
	Preferred stock dividend	—			—			4,938
	Preferred stock discount accretion	—			—			3,298
	Gain on repurchase of preferred stock	—			—			(2,471		)
	NET INCOME AVAILABLE TO COMMON SHAREHOLDERS	$	54,165		$	46,555		$	59,117
	Statements of Cash Flows	Years Ended December 31
		2014			2013			2012
	OPERATING ACTIVITIES:
	Net income	$	54,165		$	46,555		$	64,882
	Adjustments to reconcile net income to net cash provided by operating activities:
	Equity in undistributed earnings of subsidiaries	(33,707		)	(23,994		)	(23,507		)
	Increase (decrease) in deferred taxes	(1,444		)	17			(13,030		)
	Net change in valuation of financial instruments carried at fair value	4,073			865			23,075
	(Increase) decrease in other assets	(3,822		)	(4,655		)	(496		)
	Increase (decrease) in other liabilities	222			(1,921		)	4,940
	Net cash provided from operating activities	19,487			16,867			55,864
	INVESTING ACTIVITIES:
	Funds transferred to deferred compensation trust	(26		)	(27		)	(332		)
	Net cash used by investing activities	(26		)	(27		)	(332		)
	FINANCING ACTIVITIES:
	Issuance of stock for stockholder reinvestment program	127			72			36,317
	Redemption of senior preferred stock	—			—			(121,528		)
	Cash dividends paid	(13,462		)	(7,798		)	(6,470		)
	Net cash used by financing activities	(13,335		)	(7,726		)	(91,681		)
	NET INCREASE (DECREASE) IN CASH	6,126			9,114			(36,149		)
	CASH, BEGINNING OF PERIOD	45,998			36,884			73,033
	CASH, END OF PERIOD	$	52,124		$	45,998		$	36,884

STOCK_REPURCHASES

STOCK REPURCHASES	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
STOCK REPURCHASE	STOCK REPURCHASES
	During 2012, the Company repurchased or redeemed all of its Series A Preferred Stock, realizing gains aggregating $2.5 million, which was partially offset by accelerated amortization of a portion of the initial discount recorded at the issuance of the Series A Preferred Stock. As a result, the accrual for the quarterly dividend was reduced by the retirement of the repurchased shares. As of December 31, 2012, all of the Series A Preferred Stock had been retired.
	On March 26, 2014, the Company announced that its Board of Directors had authorized the repurchase of up to 978,826 shares of the Company's common stock, or 5% of the Company's outstanding shares. Under the plan, shares may be repurchased by the Company in open market purchases. The extent to which the Company repurchases its shares and timing of such repurchases will depend upon market conditions and other corporate considerations.
	The Company did not repurchase any of its common stock during the years ended December 31, 2014, 2013 or 2012 except for shares surrendered by employees to satisfy tax withholding obligations upon the vesting of restricted stock grants and shares redeemed relating to the termination of the ESOP.

CALCULATION_OF_EARNINGS_PER_CO

CALCULATION OF EARNINGS PER COMMON SHARE	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
CALCULATION OF EARNINGS PER COMMON SHARE	CALCULATION OF EARNINGS PER COMMON SHARE
	The following tables show the calculation of earnings (loss) per common share (in thousands, except per share data):
		Years Ended December 31
		2014		2013		2012
	Net income	$	54,165	$	46,555	$	64,882
	Preferred stock dividend accrual	—		—		(4,938		)
	Preferred stock discount accretion	—		—		(3,298		)
	Gain on repurchase of preferred stock	—		—		2,471
	Net income available to common shareholders	$	54,165	$	46,555	$	59,117
	Weighted average number of common shares outstanding
	Basic	19,359		19,361		18,650
	Diluted	19,403		19,397		18,723
	Earnings per common share
	Basic	$	2.8	$	2.4	$	3.17
	Diluted	$	2.79	$	2.4	$	3.16
	At December 31, 2014, there were 195,106 issued but unvested restricted stock shares that were included in the computation of diluted earnings per share.
	Options to purchase an additional 10,664 shares of common stock and a warrant to purchase up to 243,998 shares of common stock were not included in the computation of diluted earnings per share because their exercise price resulted in them being anti-dilutive.

SELECTED_QUARTERLY_FINANCIAL_D

SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED)	12 Months Ended
	Dec. 31, 2014
Selected Quarterly Financial Information [Abstract]
SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED)	SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED)
	Results of operations on a quarterly basis for the years ended December 31, 2014, 2013 and 2012 were as follows (dollars in thousands except for per share data):
		Year Ended December 31, 2014
		First		Second			Third			Fourth
		Quarter		Quarter			Quarter			Quarter
	Interest income	$	45,106	$	46,540		$	49,764		$	49,251
	Interest expense	2,767		2,732			2,700			2,590
	Net interest income before provision for loan losses	42,339		43,808			47,064			46,661
	Provision for loan losses	—		—			—			—
	Net interest income	42,339		43,808			47,064			46,661
	Other operating income	8,858		20,133			13,350			11,913
	Other operating expenses	35,581		38,435			38,495			41,230
	Income before provision for income taxes	15,616		25,506			21,919			17,344
	Provision for income taxes	5,046		8,499			7,076			5,599
	Net income	10,570		17,007			14,843			11,745
	Preferred stock dividend	—		—			—			—
	Preferred stock discount accretion	—		—			—			—
	Gain on repurchase and retirement of preferred stock	—		—			—			—
	Net income available to common shareholders	$	10,570	$	17,007		$	14,843		$	11,745
	Basic earnings per share	$	0.55	$	0.88		$	0.77		$	0.61
	Diluted earnings per share	0.54		0.88			0.76			0.6
	Dividends declared	0.18		0.18			0.18			0.18
		Year Ended December 31, 2013
		First		Second			Third			Fourth
		Quarter		Quarter			Quarter			Quarter
	Interest income	$	44,508	$	45,571		$	45,037		$	44,595
	Interest expense	3,540		3,323			3,144			2,988
	Net interest income before provision for loan losses	40,968		42,248			41,893			41,607
	Provision for loan losses	—		—			—			—
	Net interest income	40,968		42,248			41,893			41,607
	Other operating income	9,997		10,623			10,142			12,580
	Other operating expenses	34,099		35,457			34,490			36,929
	Income before provision for income taxes	16,866		17,414			17,545			17,258
	Provision for income taxes	5,284		5,661			5,880			5,704
	Net income	11,582		11,753			11,665			11,554
	Preferred stock dividend	—		—			—			—
	Preferred stock discount accretion	—		—			—			—
	Gain on repurchase and retirement of preferred stock	—		—			—			—
	Net income available to common shareholders	$	11,582	$	11,753		$	11,665		$	11,554
	Basic earnings per share	$	0.6	$	0.6		$	0.6		$	0.6
	Diluted earnings per share	0.6		0.6			0.6			0.6
	Dividends declared	0.12		0.12			0.15			0.15
		Year Ended December 31, 2012
		First		Second			Third			Fourth
		Quarter		Quarter			Quarter			Quarter
	Interest income	$	47,198	$	47,265		$	47,174		$	45,525
	Interest expense	6,072		4,975			4,476			3,991
	Net interest income before provision for loan losses	41,126		42,290			42,698			41,534
	Provision for loan losses	5,000		4,000			3,000			1,000
	Net interest income	36,126		38,290			39,698			40,534
	Other operating income	10,971		(9,064		)	11,684			13,311
	Other operating expenses	37,913		35,666			33,355			34,519
	Income (loss) before provision for income taxes	9,184		(6,440		)	18,027			19,326
	Provision (benefit) for income taxes	—		(31,830		)	2,407			4,638
	Net income	9,184		25,390			15,620			14,688
	Preferred stock dividend	1,550		1,550			1,227			611
	Preferred stock discount accretion	454		454			1,216			1,174
	Gain on repurchase and retirement of preferred stock	—		—			(2,070		)	(401		)
	Net income available to common shareholders	$	7,180	$	23,386		$	15,247		$	13,304
	Basic earnings per share	$	0.4	$	1.27		$	0.81		$	0.69
	Diluted earnings per share	0.4		1.27			0.8			0.69
	Dividends declared	0.01		0.01			0.01			0.01

FINANCIAL_INSTRUMENTS_WITH_OFF

FINANCIAL INSTRUMENTS WITH OFF-BALANCE-SHEET RISK	12 Months Ended
	Dec. 31, 2014
Financial Instruments with Off-Balance-Sheet Risk [Abstract]
FINANCIAL INSTRUMENTS WITH OFF-BALANCE SHEET RISK	FINANCIAL INSTRUMENTS WITH OFF-BALANCE-SHEET RISK
	The Company has financial instruments with off-balance-sheet risk generated in the normal course of business to meet the financing needs of its customers.  These financial instruments include commitments to extend credit, commitments related to standby letters of credit, commitments to originate loans, commitments to sell loans, and commitments to buy or sell securities. These instruments involve, to varying degrees, elements of credit and interest rate risk similar to the risk involved in on-balance sheet items recognized in our Consolidated Statements of Financial Condition.
	Our exposure to credit loss in the event of nonperformance by the other party to the financial instrument from commitments to extend credit and standby letters of credit is represented by the contractual notional amount of those instruments.  We use the same credit policies in making commitments and conditional obligations as for on-balance sheet instruments.
	Outstanding commitments for which no asset or liability for the notional amount has been recorded consisted of the following at the dates indicated (in thousands):
		Contract or Notional Amount
		December 31, 2014		December 31, 2013
	Commitments to extend credit	$	1,166,165	$	1,073,897
	Standby letters of credit and financial guarantees	9,934		6,990
	Commitments to originate loans	20,988		15,776
	Derivatives also included in Note 28:
	Commitments to originate loans held for sale	29,851		21,434
	Commitments to sell loans secured by one- to four-family residential properties	8,714		9,378
	Commitments to sell securities related to mortgage banking activities	25,000		15,200
	Commitments to extend credit are agreements to lend to a customer, as long as there is no violation of any condition established in the contract.  Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee.  Many of the commitments may expire without being drawn upon; therefore, the total commitment amounts do not necessarily represent future cash requirements.  Each customer’s creditworthiness is evaluated on a case-by-case basis.  The amount of collateral obtained, if deemed necessary upon extension of credit, is based on management’s credit evaluation of the customer.  Collateral held varies, but may include accounts receivable, inventory, property, plant and equipment, and income producing commercial properties.
	Standby letters of credit are conditional commitments issued to guarantee a customer’s performance or payment to a third party.  The credit risk involved in issuing letters of credit is essentially the same as that involved in extending loan facilities to customers.
	Interest rates on residential one- to four-family mortgage loan applications are typically rate locked (committed) to customers during the application stage for periods ranging from 30 to 60 days, the most typical period being 45 days. Traditionally, these loan applications with rate lock commitments had the pricing for the sale of these loans locked with various qualified investors under a best-efforts delivery program at or near the time the interest rate is locked with the customer. The Bank then attempts to deliver these loans before their rate locks expired. This arrangement generally required delivery of the loans prior to the expiration of the rate lock. Delays in funding the loans required a lock extension. The cost of a lock extension at times was borne by the customer and at times by the Bank. These lock extension costs have not had a material impact to our operations. In 2012, the Company also began entering into forward commitments at specific prices and settlement dates to deliver either: (1) residential mortgage loans for purchase by secondary market investors (i.e., Freddie Mac or Fannie Mae), or (2) mortgage-backed securities to broker/dealers. The purpose of these forward commitments is to offset the movement in interest rates between the execution of its residential mortgage rate lock commitments with borrowers and the sale of those loans to the secondary market investor. There were no counterparty default losses on forward contracts during 2014 or 2013. Market risk with respect to forward contracts arises principally from changes in the value of contractual positions due to changes in interest rates. The Company limits its exposure to market risk by monitoring differences between commitments to customers and forward contracts with market investors and securities broker/dealers. In the event the Company has forward delivery contract commitments in excess of available mortgage loans, the transaction is completed by either paying or receiving a fee to or from the investor or broker/dealer equal to the increase or decrease in the market value of the forward contract. Changes in the value of rate lock commitments are recorded as assets and liabilities as explained in Note 1: “Derivative Instruments.”

DERIVATIVES_AND_HEDGING_DERIVA

DERIVATIVES AND HEDGING DERIVATIVES AND HEDGING	12 Months Ended
	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVES AND HEDGING	DERIVATIVES AND HEDGING
	The Company, through its Banner Bank subsidiary, is party to various derivative instruments that are used for asset and liability management and customer financing needs. Derivative instruments are contracts between two or more parties that have a notional amount and an underlying variable, require no net investment and allow for the net settlement of positions. The notional amount serves as the basis for the payment provision of the contract and takes the form of units, such as shares or dollars. The underlying variable represents a specified interest rate, index, or other component. The interaction between the notional amount and the underlying variable determines the number of units to be exchanged between the parties and influences the market value of the derivative contract. The Company obtains dealer quotations to value its derivative contracts.
	The Company's predominant derivative and hedging activities involve interest rate swaps related to certain term loans and forward sales contracts associated with mortgage banking activities. Generally, these instruments help the Company manage exposure to market risk and meet customer financing needs. Market risk represents the possibility that economic value or net interest income will be adversely affected by fluctuations in external factors such as market-driven interest rates and prices or other economic factors.
	Derivatives Designated in Hedge Relationships
	The Company's fixed rate loans result in exposure to losses in value or net interest income as interest rates change. The risk management objective for hedging fixed rate loans is to effectively convert the fixed rate received to a floating rate. The Company has hedged exposure to changes in the fair value of certain fixed rate loans through the use of interest rate swaps. For a qualifying fair value hedge, changes in the value of the derivatives are recognized in current period earnings along with the corresponding changes in the fair value of the designated hedged item attributable to the risk being hedged.
	In a program brought to Banner Bank through its merger with F&M Bank in 2007, customers received fixed interest rate commercial loans and the Bank subsequently hedged that fixed rate loan by entering into an interest rate swap with a dealer counterparty. The Bank receives fixed rate payments from the customers on the loans and makes similar fixed rate payments to the dealer counterparty on the swaps in exchange for variable rate payments based on the one-month LIBOR index. Some of these interest rate swaps are designated as fair value hedges. Through application of the “short cut method of accounting,” there is an assumption that the hedges are effective. The Bank discontinued originating interest rate swaps under this program in 2008.
	As of December 31, 2014 and December 31, 2013, the notional values or contractual amounts and fair values of the Company's derivatives designated in hedge relationships were as follows (in thousands):
		Asset Derivatives													Liability Derivatives
		December 31, 2014								December 31, 2013					December 31, 2014					December 31, 2013
		Notional/				Fair				Notional/		Fair			Notional/			Fair		Notional/		Fair
		Contract Amount				Value (1)				Contract Amount		Value (1)			Contract Amount			Value (2)		Contract Amount		Value (2)
	Interest rate swaps	$	7,089			$	1,165			$	7,420	$	1,295		$	7,089		$	1,165	$	7,420	$	1,295
	(1)	Included in Loans Receivable on the Consolidated Statement of Financial Condition.
	(2)	Included in Other Liabilities on the Consolidated Statement of Financial Condition.
	Derivatives Not Designated in Hedge Relationships
	Interest Rate Swaps: Banner Bank, has been using an interest rate swap program for commercial loan customers, termed the Back-to-Back Program, since 2010. In the Back-to-Back Program, the Bank provides the client with a variable rate loan and enters into an interest rate swap in which the client receives a variable rate payment in exchange for a fixed rate payment. The Bank offsets its risk exposure by entering into an offsetting interest rate swap with a dealer counterparty for the same notional amount and length of term as the client interest rate swap providing the dealer counterparty with a fixed rate payment in exchange for a variable rate payment. There are also a few interest rate swaps from prior to 2009 that were not designated in hedge relationships that are included in these totals. These swaps do not qualify as designated hedges; therefore, each swap is accounted for as a free standing derivative.
	Mortgage Banking: In the normal course of business, the Company sells originated mortgage loans into the secondary mortgage loan markets. During the period of loan origination and prior to the sale of the loans in the secondary market, the Company has exposure to movements in interest rates associated with written rate lock commitments with potential borrowers to originate loans that are intended to be sold and for closed loans that are awaiting sale and delivery into the secondary market.
	Written loan commitments that relate to the origination of mortgage loans that will be held for resale are considered free-standing derivatives and do not qualify for hedge accounting. Written loan commitments generally have a term of up to 60 days before the closing of the loan. The loan commitment does not bind the potential borrower to enter into the loan, nor does it guarantee that the Company will approve the potential borrower for the loan. Therefore, when determining fair value, the Company makes estimates of expected “fallout” (loan commitments not expected to close), using models which consider cumulative historical fallout rates, current market interest rates and other factors.
	Written loan commitments in which the borrower has locked in an interest rate results in market risk to the Company to the extent market interest rates change from the rate quoted to the borrower. The Company economically hedges the risk of changing interest rates associated with its interest rate lock commitments by entering into forward sales contracts.
	Mortgage loans which are held for sale are subject to changes in fair value due to fluctuations in interest rates from the loan's closing date through the date of sale of the loans into the secondary market. Typically, the fair value of these loans declines when interest rates increase and rises when interest rates decrease. To mitigate this risk, the Company enters into forward sales contracts on a significant portion of these loans to provide an economic hedge against those changes in fair value. Mortgage loans held for sale and the forward sales contracts are recorded at fair value with ineffective changes in value recorded in current earnings as loan sales and servicing income.
	As of December 31, 2014 and December 31, 2013, the notional values or contractual amounts and fair values of the Company's derivatives not designated in hedge relationships were as follows (in thousands):
		Asset Derivatives													Liability Derivatives
		December 31, 2014								December 31, 2013					December 31, 2014					December 31, 2013
		Notional/				Fair				Notional/		Fair			Notional/			Fair		Notional/		Fair
		Contract Amount				Value (1)				Contract Amount		Value (1)			Contract Amount			Value (2)		Contract Amount		Value (2)
	Interest rate swaps	$	134,512			$	5,125			$	135,122	$	3,651		$	134,512		$	5,125	$	135,122	$	3,651
	Mortgage loan commitments	29,311				317				14,107		57			—			—		7,326		43
	Forward sales contracts	—				—				22,526		73			33,174			198		—		—
		$	163,823			$	5,442			$	171,755	$	3,781		$	167,686		$	5,323	$	142,448	$	3,694
	(1)	Included in Other Assets on the Consolidated Statements of Financial Condition, with the exception of those interest rate swaps from prior to 2009 that were not designated in hedge relationships (with a fair value of $558,000 at December 31, 2014 and $791,000 at December 31, 2013), which are included in Loans Receivable.
	(2)	Included in Other Liabilities on the Consolidated Statements of Financial Condition.
	Gains (losses) recognized in income on non-designated hedging instruments for the years ended December 31, 2014 and 2013 were as follows (in thousands):
				For the Year Ended December 31
		Location on Income Statement		2014				2013
	Mortgage loan commitments	Mortgage banking operations		$	221			$	(174	)
	Forward sales contracts	Mortgage banking operations		(188		)		310
				$	33			$	136
	The Company is exposed to credit-related losses in the event of nonperformance by the counterparty to these agreements. Credit risk of the financial contract is controlled through the credit approval, limits, and monitoring procedures and management does not expect the counterparties to fail their obligations.
	In connection with the interest rate swaps between Banner Bank and the dealer counterparties, the agreements contain a provision where if Banner Bank fails to maintain its status as a well/adequately capitalized institution, then the counterparty could terminate the derivative positions and Banner Bank would be required to settle its obligations. Similarly, Banner Bank could be required to settle its obligations under certain of its agreements if specific regulatory events occur, such as a publicly issued prompt corrective action directive, cease and desist order, or a capital maintenance agreement that required Banner Bank to maintain a specific capital level. If Banner Bank had breached any of these provisions at December 31, 2014 or December 31, 2013, it could have been required to settle its obligations under the agreements at the termination value. As of December 31, 2014 and 2013, the termination value of derivatives in a net liability position related to these agreements was $6.3 million and $2.7 million, respectively. The Company generally posts collateral against derivative liabilities in the form of government agency-issued bonds, mortgage-backed securities, or commercial mortgage-backed securities. Collateral posted against derivative liabilities was $11.1 million and $8.9 million as of December 31, 2014 and 2013, respectively.
	Derivative assets and liabilities are recorded at fair value on the balance sheet and do not take into account the effects of master netting agreements. Master netting agreements allow the Company to settle all derivative contracts held with a single counterparty on a net basis and to offset net derivative positions with related collateral where applicable.
	The following table illustrates the potential effect of the Company's derivative master netting arrangements, by type of financial instrument, on the Company's Consolidated Statements of Financial Condition as of December 31, 2014 and December 31, 2013 (in thousands):
		December 31, 2014
												Gross Amounts of Financial Instruments Not Offset in the Statement of Financial Condition
		Gross Amounts Recognized				Amounts offset in the Statement				Net Amounts		Netting Adjustment Per Applicable Master Netting Agreements			Fair Value			Net Amount
						of Financial Condition				in the Statement					of Financial Collateral
										of Financial Condition					in the Statement
															of Financial Condition
	Derivative assets
	Interest rate swaps	$	6,290			$	—			$	6,290	$	(6	)	$	—		$	6,284
		$	6,290			$	—			$	6,290	$	(6	)	$	—		$	6,284
	Derivative liabilities
	Interest rate swaps	$	6,290			$	—			$	6,290	$	(6	)	$	(6,279	)	$	5
		$	6,290			$	—			$	6,290	$	(6	)	$	(6,279	)	$	5
		December 31, 2013
												Gross Amounts of Financial Instruments Not Offset in the Statement of Financial Condition
		Gross Amounts Recognized				Amounts offset in the Statement				Net Amounts		Netting Adjustment Per Applicable Master Netting Agreements			Fair Value			Net Amount
						of Financial Condition				in the Statement					of Financial Collateral
										of Financial Condition					in the Statement
															of Financial Condition
	Derivative assets
	Interest rate swaps	$	4,946			$	—			$	4,946	$	(554	)	$	—		$	4,392
		$	4,946			$	—			$	4,946	$	(554	)	$	—		$	4,392
	Derivative liabilities
	Interest rate swaps	$	4,946			$	—			$	4,946	$	(554	)	$	(2,657	)	$	1,735
	$	4,946			$	—			$	4,946	$	(554	)	$	(2,657	)	$	1,735

BASIS_OF_PRESENTATION_AND_SUMM1

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Principles of Consolidation	Principles of Consolidation:  The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries.  All material intercompany transactions, profits and balances have been eliminated.
Subsequent Events	Subsequent Events: The Company has evaluated events and transactions subsequent to December 31, 2014 for potential recognition or disclosure through March 16, 2015, which is the date the financial statements were available to be issued.
Business Combinations	Business Combinations: Business combinations are accounted for using the acquisition method of accounting. Under the acquisition method of accounting, assets acquired and liabilities assumed are recorded at estimated fair value at the date of acquisition. Any difference in purchase consideration over the fair value of assets acquired and liabilities assumed results in the recognition of goodwill should purchase consideration exceed net estimated fair values, or a bargain purchase gain, should estimated fair values exceed purchase consideration. Expenses incurred in connection with a business combination are expensed as incurred. Changes in deferred tax asset valuation allowances acquired tax uncertainties after the measurement period are recognized in net income.
Use of Estimates	Use of Estimates:  In the opinion of management, the accompanying consolidated statements of financial condition and related consolidated statements of operations, comprehensive income (loss), changes in stockholders’ equity and cash flows reflect all adjustments (which include reclassification and normal recurring adjustments) that are necessary for a fair presentation in conformity with U.S. Generally Accepted Accounting Principles (GAAP).  The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect amounts reported in the financial statements.  Various elements of the Company’s accounting policies, by their nature, are inherently subject to estimation techniques, valuation assumptions and other subjective assessments.  In particular, management has identified several accounting policies that, due to the judgments, estimates and assumptions inherent in those policies, are critical to an understanding of Banner’s financial statements.  These policies relate to (i) the methodology for the recognition of interest income, (ii) determination of the provision and allowance for loan and lease losses, (iii) the valuation of financial assets and liabilities recorded at fair value, including other-than-temporary impairment (OTTI) losses, (iv) the valuation of intangibles, such as core deposit intangibles and mortgage servicing rights, (v) the valuation of real estate held for sale and (vi) the valuation of or recognition of deferred tax assets and liabilities.  These policies and judgments, estimates and assumptions are described in greater detail in subsequent notes to the consolidated financial statements and Management’s Discussion and Analysis of Financial Condition and Results of Operations (Critical Accounting Policies) in this Annual Report on Form 10-K for the year ended December 31, 2014 filed with the Securities and Exchange Commission (SEC).  Management believes that the judgments, estimates and assumptions used in the preparation of the financial statements are appropriate based on the factual circumstances at the time.  However, given the sensitivity of the financial statements to these critical accounting policies, the use of other judgments, estimates and assumptions could result in material differences in the Company’s results of operations or financial condition.  Further, subsequent changes in economic or market conditions could have a material impact on these estimates and the Company’s financial condition and operating results in future periods.
Securities	Securities: Securities are classified as held-to-maturity when the Company has the ability and positive intent to hold them to maturity.  Securities classified as available-for-sale are available for future liquidity requirements and may be sold prior to maturity.  Securities classified as trading are also available for future liquidity requirements and may be sold prior to maturity.  Purchase premiums and discounts are recognized in interest income using the interest method over the terms of the securities.  Securities classified as held-to-maturity are carried at cost, adjusted for amortization of premiums and accretion of discounts to maturity and, if appropriate, any other-than-temporary impairment losses.  Securities classified as available-for-sale are recorded at fair value.  Unrealized holding gains and losses on securities classified as available-for-sale are excluded from earnings and are reported net of tax as accumulated other comprehensive income (loss), a component of stockholders’ equity, until realized.  Securities classified as trading are also recorded at fair value.  Unrealized holding gains and losses on securities classified as trading are included in earnings.  (See Note 22 for a more complete discussion of accounting for the fair value of financial instruments.)  Declines in the fair value of securities below their cost that are deemed to be other-than-temporary are recognized in earnings as realized losses.  Realized gains and losses on sale are computed on the specific identification method and are included in earnings on the trade date sold.
	The Company reviews investment securities on an ongoing basis for the presence of OTTI or permanent impairment, taking into consideration current market conditions, fair value in relationship to cost, extent and nature of the change in fair value, issuer rating changes and trends, whether the Company intends to sell a security or if it is likely that it will be required to sell the security before recovery of the amortized cost basis of the investment, which may be maturity, and other factors.
	For debt securities, if the Company intends to sell the security or it is likely that the Company will be required to sell the security before recovering its cost basis, the entire impairment loss would be recognized in earnings as an OTTI.  If the Company does not intend to sell the security and it is not likely that the Company will be required to sell the security but the Company does not expect to recover the entire amortized cost basis of the security, only the portion of the impairment loss representing credit losses would be recognized in earnings.  The credit loss on a security is measured as the difference between the amortized cost basis and the present value of the cash flows expected to be collected.  Projected cash flows are discounted by the original or current effective interest rate depending on the nature of the security being measured for potential OTTI.  The remaining impairment related to all other factors, the difference between the present value of the cash flows expected to be collected and fair value, is recognized as a charge to other comprehensive income (OCI).  Impairment losses related to all other factors are presented as separate categories within OCI.
	For investment securities transferred from held-to-maturity to available-for-sale, unrealized gains or losses from the time of transfer are accreted or amortized over the remaining life of the debt security based on the amount and timing of future estimated cash flows.  The accretion or amortization of the amount recorded in OCI increases the carrying value of the investment and does not affect earnings.
Investment in FHLB Stock	Investment in FHLB Stock: At December 31, 2014, the Company had $27.0 million in FHLB stock, compared to $35.4 million at December 31, 2013. The Banks' investments in FHLB stock are generally viewed as a long-term investment and are carried at par value ($100 per share), which reasonably approximates its fair value. FHLB stock does not have a readily determinable fair value. Ownership of FHLB stock is restricted to the FHLB and member institutions and can only be purchased and redeemed at par. As members of the FHLB system, the Banks are required to maintain a minimum level of investment in FHLB stock based on specific percentages of their outstanding FHLB advances.
	Management periodically evaluates FHLB stock for impairment. Management's determination of whether these investments are impaired is based on its assessment of the ultimate recoverability of cost rather than by recognizing temporary declines in value. The determination of whether a decline affects the ultimate recoverability of cost is influenced by criteria such as (1) the significance of any decline in net assets of the FHLB as compared to the capital stock amount for the FHLB and the length of time this situation has persisted, (2) commitments by the FHLB to make payments required by law or regulation and the level of such payments in relation to the operating performance of the FHLB, (3) the impact of legislative and regulatory changes on institutions and, accordingly, the customer base of the FHLB, and (4) the liquidity position of the FHLB.
	The FHLB of Seattle announced that it had a risk-based capital deficiency under the regulations of the Federal Housing Finance Agency (the FHFA), its primary regulator, as of December 31, 2008, and that it would suspend future dividends and the repurchase and redemption of outstanding common stock. The FHLB of Seattle announced on September 7, 2012 that the FHFA now considers the FHLB of Seattle to be adequately capitalized. Dividends on, or repurchases of, the FHLB of Seattle stock continue to require consent of the FHFA. The FHFA subsequently approved the repurchase of portions of FHLB of Seattle stock, and as of December 31, 2014, the FHLB had repurchased $9.7 million of the Banks' stock. For the years ended December 31, 2012 and 2011, the Banks did not receive any dividend income on FHLB stock. The FHLB continued to progress and on November 11, 2013 an Amended Consent Arrangement was agreed to with the FHLB's regulator. During the year ended December 31, 2013, the FHLB of Seattle paid two dividends, one in August and one in October, totaling $18,000 in dividend income for that year. During the year ended December 31, 2014, the FHLB of Seattle paid four dividends totaling $34,000 in dividend income for the Banks for the year.
	On September 25, 2014, the FHLB Seattle and FHLB Des Moines announced a proposed merger. Under this proposal, each of our Banks would become a member of FHLB Des Moines and all shares of our FHLB Seattle stock would convert to equal shares of FHLB Des Moines stock. If the merger is terminated by either the FHLB Des Moines or the FHLB Seattle, the terminating FHLB must pay $57 million in termination fees. If the FHLB Seattle were to terminate the agreement, this could result in significant impairment to our investment in the FHLB Seattle, potentially decreasing our earnings and shareholders' equity. The Company will continue to monitor the financial condition of the FHLB of Seattle as it relates to, among other things, the recoverability of Banner's investment. Based on the above, the Company has determined there is not any impairment on the FHLB stock investment as of December 31, 2014.
Loans Receivable	Loans Receivable:  The Banks originate residential mortgage loans for both portfolio investment and sale in the secondary market.  At the time of origination, mortgage loans are designated as held for sale or held for investment.  Loans held for sale are stated at lower of cost or estimated market value determined on an aggregate basis.  Net unrealized losses on loans held for sale are recognized through a valuation allowance by charges to income.  The Banks also originate construction and land development, commercial and multifamily real estate, commercial business, agricultural and consumer loans for portfolio investment.  Loans receivable not designated as held for sale are recorded at the principal amount outstanding, net of allowance for loan losses, deferred fees, discounts and premiums.  Premiums, discounts and deferred loan fees are amortized to maturity using the level-yield methodology.
	Some of the Company’s loans are reported as troubled debt restructures (TDRs).  Loans are reported as restructured when the Bank grants a concession(s) to a borrower experiencing financial difficulties that it would not otherwise consider.  Examples of such concessions include forgiveness of principal or accrued interest, extending the maturity date(s) or providing a lower interest rate than would be normally available for a transaction of similar risk.  As a result of these concessions, loans identified as TDRs are impaired as the Bank will not collect all amounts due, both principal and interest, in accordance with the terms of the original loan agreement.  TDRs are accounted for in accordance with the Banks’ impaired loan accounting policies.
Income Recognition on Nonaccrual and Impaired Loans	Income Recognition on Nonaccrual and Impaired Loans:  Interest on loans and securities is accrued as earned unless management doubts the collectability of the asset or the unpaid interest.  Interest accruals on loans are generally discontinued when loans become 90 days past due for payment of interest and the loans are then placed on nonaccrual status.  All previously accrued but uncollected interest is deducted from interest income upon transfer to nonaccrual status.  For any future payments collected, interest income is recognized only upon management’s assessment that there is a strong likelihood that the full amount of a loan will be repaid or recovered.  A loan may be put on nonaccrual status sooner than this policy would dictate if, in management’s judgment, the interest may be uncollectable.  While less common, similar interest reversal and nonaccrual treatment is applied to investment securities if their ultimate collectability becomes questionable.
Provision and Allowance for Loan Losses	Provision and Allowance for Loan Losses:  The provision for loan losses reflects the amount required to maintain the allowance for losses at an appropriate level based upon management’s evaluation of the adequacy of general and specific loss reserves.  The Company maintains an allowance for loan losses consistent in all material respects with generally accepted accounting principles.  The Company has established systematic methodologies for the determination of the adequacy of the Company’s allowance for loan losses.  The methodologies are set forth in a formal policy and take into consideration the need for a general valuation allowance as well as specific allowances that are tied to individual problem loans.  The Company increases its allowance for loan losses by charging provisions for probable loan losses against its income and values impaired loans consistent with accounting guidelines.
	The allowance for losses on loans is maintained at a level sufficient to provide for estimated losses based on evaluating known and inherent risks in the loan portfolio and upon the Company’s continuing analysis of the factors underlying the quality of the loan portfolio.  These factors include, among others, changes in the size and composition of the loan portfolio, delinquency rates, actual loan loss experience, current and anticipated economic conditions, detailed analysis of individual loans for which full collectability may not be assured, and determination of the existence and realizable value of the collateral and guarantees securing the loans.  Realized losses related to specific assets are applied as a reduction of the carrying value of the assets and charged immediately against the allowance for loan loss reserve.  Recoveries on previously charged off loans are credited to the allowance.  The reserve is based upon factors and trends identified by Banner at the time financial statements are prepared.  Although the Company uses the best information available, future adjustments to the allowance may be necessary due to economic, operating, regulatory and other conditions beyond the Company’s control.  The adequacy of general and specific reserves is based on a continuing evaluation of the pertinent factors underlying the quality of the loan portfolio as well as individual review of certain large balance loans.  Large groups of smaller-balance homogeneous loans are collectively evaluated for impairment.  Loans that are collectively evaluated for impairment include residential real estate and consumer loans and, as appropriate, smaller balance non-homogeneous loans.  Larger balance non-homogeneous residential construction and land, commercial real estate, commercial business loans and unsecured loans are individually evaluated for impairment.  Loans are considered impaired when, based on current information and events, the Company determines that it is probable that it will be unable to collect all amounts due according to the contractual terms of the loan agreement.  Factors involved in determining impairment include, but are not limited to, the financial condition of the borrower and the value of the underlying collateral.  Impaired loans are measured based on the present value of expected future cash flows discounted at the loan’s effective interest rate or, as a practical expedient, at the loan’s observable market price or the fair value of collateral if the loan is collateral dependent.  Subsequent changes in the value of impaired loans are included within the provision for loan losses in the same manner in which impairment initially was recognized or as a reduction in the provision that would otherwise be reported.
	The Company’s methodology for assessing the appropriateness of the allowance consists of several key elements, which include specific allowances, an allocated formula allowance and an unallocated allowance.  Losses on specific loans are provided for when the losses are probable and estimable.  General loan loss reserves are established to provide for inherent loan portfolio risks not specifically provided for.  The level of general reserves is based on analysis of potential exposures existing in the loan portfolio including evaluation of historical trends, current market conditions and other relevant factors identified by us at the time the financial statements are prepared.  The formula allowance is calculated by applying loss factors to outstanding loans, excluding those loans that are subject to individual analysis for specific allowances.  Loss factors are based on the Company’s historical loss experience adjusted for significant environmental considerations, including the experience of other banking organizations, which in the judgment of management affects the collectability of the portfolio as of the evaluation date.  The unallocated allowance is based upon the Company’s evaluation of various factors that are not directly measured in the determination of the formula and specific allowances.
	While the Company believes the estimates and assumptions used in the determination of the adequacy of the allowance are reasonable, there can be no assurance that such estimates and assumptions will not be proved incorrect in the future, or that the actual amount of future provisions will not exceed the amount of past provisions or that any increased provisions that may be required will not adversely impact the financial condition and results of operations of the Company.  In addition, the determination of the amount of the allowance for loan losses is subject to review by bank regulators as part of the routine examination process, which may result in the adjustment of reserves based upon their judgment of information available to them at the time of their examination.
Loan Origination and Commitment Fees	Loan Origination and Commitment Fees:  Loan origination fees, net of certain specifically defined direct loan origination costs, are deferred and recognized as an adjustment of the loans’ interest yield using the level-yield method over the contractual term of each loan adjusted for actual loan prepayment experience.  Net deferred fees or costs related to loans held for sale are recognized in income at the time the loans are sold.  Loan commitment fees are deferred until the expiration of the commitment period unless management believes there is a remote likelihood that the underlying commitment will be exercised, in which case the fees are amortized to fee income using the straight-line method over the commitment period.  If a loan commitment is exercised, the deferred commitment fee is accounted for in the same manner as a loan origination fee.  Deferred commitment fees associated with expired commitments are recognized as fee income.
Real Estate Held for Sale	Real Estate Held for Sale: Property acquired by foreclosure or deed in lieu of foreclosure is recorded at the lower of the estimated fair value of the property, less expected selling costs, or the carrying value of the defaulted loan.  Development and improvement costs relating to the property are capitalized while direct holding costs are expensed.  The carrying value of the property is periodically evaluated by management and, if necessary, allowances are established to reduce the carrying value to net realizable value.  Gains or losses at the time the property is sold are charged or credited to operations in the period in which they are realized.  The amounts the Banks will ultimately recover from real estate held for sale may differ substantially from the carrying value of the assets because of market factors beyond the Banks’ control or because of changes in the Banks’ strategies for recovering the investment.
Property and Equipment	Property and Equipment:  The provision for depreciation is based upon the straight-line method applied to individual assets and groups of assets acquired in the same year at rates adequate to charge off the related costs over their estimated useful lives:
	Buildings and leased improvements	10–30 years
	Furniture and equipment	3–10 years
	Routine maintenance, repairs and replacement costs are expensed as incurred.  Expenditures which significantly increase values or extend useful lives are capitalized.  The Company reviews buildings, leasehold improvements and equipment for impairment whenever events or changes in circumstances indicate that the undiscounted cash flows for the property are less than its carrying value.  If identified, an impairment loss is recognized through a charge to earnings based on the fair value of the property.
Other Intangible Assets	Other Intangible Assets:  Other intangible assets consist primarily of core deposit intangibles (CDI), which are amounts recorded in business combinations or deposit purchase transactions related to the value of transaction-related deposits and the value of the customer relationships associated with the deposits.  Core deposit intangibles are being amortized on an accelerated basis over a weighted average estimated useful life of three to eight years.  These assets are reviewed at least annually for events or circumstances that could impact their recoverability.  These events could include loss of the underlying core deposits, increased competition or adverse changes in the economy.  To the extent other identifiable intangible assets are deemed unrecoverable, impairment losses are recorded in other non-interest expense to reduce the carrying amount of the assets.
Mortgage Servicing Rights	Mortgage Servicing Rights: Servicing assets are recognized as separate assets when rights are acquired through purchase or sale of loans.  Generally, purchased servicing rights are capitalized at the cost to acquire the rights.  For sales of mortgage loans, the value of the servicing right is estimated and capitalized.  Fair value is based on market prices for comparable mortgage servicing contracts.  Capitalized servicing rights are reported in other assets and are amortized into non-interest income in proportion to, and over the period of, the estimated future net servicing income of the underlying financial assets.
	Servicing assets are evaluated for impairment based upon the fair value of the rights as compared to amortized cost.  Impairment is determined by stratifying rights into tranches based on predominant risk characteristics for the underlying loans, such as interest rate, balance outstanding, loan type, age and remaining term, and investor type.  Impairment is recognized through a valuation allowance for an individual tranche, to the extent that fair value is less than the capitalized amount for the tranche.  If the Company later determines that all or a portion of the impairment no longer exists for a particular tranche, a reduction of the allowance may be recorded as an increase to income.
	Servicing fee income is recorded for fees earned for servicing loans and is reflected in mortgage banking operations on the consolidated statement of operations.  The fees are based on a contractual percentage of the outstanding principal or a fixed amount per loan and are recorded as income when earned.  The amortization of mortgage servicing rights is netted against loan servicing fee income.
Bank-Owned Life Insurance (BOLI)	Bank-Owned Life Insurance (BOLI):  The Banks have purchased, or acquired through mergers, life insurance policies in connection with the implementation of certain executive supplemental income, salary continuation and deferred compensation retirement plans.  These policies provide protection against the adverse financial effects that could result from the death of a key employee and provide tax-exempt income to offset expenses associated with the plans.  It is the Banks’ intent to hold these policies as a long-term investment; however, there may be an income tax impact if the Bank chooses to surrender certain policies.  Although the lives of individual current or former management-level employees are insured, the Banks are the respective owners and sole or partial beneficiaries.  At December 31, 2014 and 2013, the cash surrender value of these policies was $63.8 million and $61.9 million, respectively.
Derivative Instruments	Derivative Instruments:  Derivatives include “off-balance-sheet” financial products, the value of which is dependent on the value of underlying financial assets, such as stock, bonds, foreign currency, or a reference rate or index.  Such derivatives include “forwards,” “futures,” “options” or “swaps.”  As a result of the 2007 acquisition of F&M Bank, Banner Bank became a party to approximately $23 million ($13 million as of December 31, 2014) in notional amounts of interest rate swaps.  Some of these swaps serve as hedges to an equal amount of fixed rate loans which include market value prepayment penalties that mirror the provision of the specifically matched interest rate swaps.  In addition, in 2011 we began actively marketing interest rate swaps to certain loan customers in connection with longer-term floating rate loans, allowing them to effectively fix their loan interest rates.  These customer swaps are matched with third party swaps with qualified broker/dealer or banks to offset the risk.  As of December 31, 2014, we had $129 million in notional amounts of these customer interest rate swaps outstanding, with an equal amount of offsetting third party swaps also in place.  The fair value adjustments for these swaps and the related loans are reflected in other assets or other liabilities as appropriate, and in the carrying value of the related loans.
	Further, as a part of its mortgage banking activities, the Company issues “rate lock” commitments to borrowers and obtains offsetting “best efforts” delivery commitments from purchasers of loans. The Company also uses forward contracts for the sale of mortgage-backed securities and mandatory delivery commitments for the sale of loans to hedge "rate lock" commitments and loans held for sale.  The commitments to originate mortgage loans held for sale and the related delivery contracts are considered derivatives.  The Company recognizes all derivatives as either assets or liabilities in the balance sheet and requires measurement of those instruments at fair value through adjustments to current earnings.  None of these residential mortgage loan related derivatives are designated as hedging instruments for accounting purposes.  Rather, they are accounted for as free-standing derivatives, or economic hedges, and the Company reports changes in fair values of its derivatives in current period net income.  The fair value of the derivative loan commitments is estimated using the present value of expected future cash flows.  Assumptions used include rate assumptions based on historical information, current mortgage interest rates, the stage of completion of the underlying application and underwriting process, the time remaining until the expiration of the derivative loan commitment, and the expected net future cash flows related to the associated servicing of the loan (see Note 28 for a more complete discussion of derivatives and hedging).
Transfers of Financial Assets	Transfers of Financial Assets:  Transfers of financial assets are accounted for as sales when control over the assets has been surrendered.  Control over transferred assets is deemed to be surrendered when (1) the assets have been isolated from the Banks, (2) the transferee obtains the right (free of conditions that constrain it from taking advantage of that right) to pledge or exchange the transferred assets, and (3) the Banks do not maintain effective control over the transferred assets through an agreement to repurchase them before their maturity.
Advertising Expenses	Advertising Expenses:  Advertising costs are expensed as incurred.  Costs related to production of advertising are considered incurred when the advertising is first used.
Income Taxes	Income Taxes:  The Company files a consolidated income tax return including all of its wholly-owned subsidiaries on a calendar year basis.  Income taxes are accounted for using the asset and liability method.  Under this method, a deferred tax asset or liability is determined based on the enacted tax rates which will be in effect when the differences between the financial statement carrying amounts and tax bases of existing assets and liabilities are expected to be reported in the Company’s income tax returns.  The effect on deferred taxes of a change in tax rates is recognized in income in the period of change. A valuation allowance is recognized as a reduction to deferred tax assets when management determines it is more likely than not that deferred tax assets will not be available to offset future income tax liabilities.
	Accounting standards for income taxes prescribe a recognition threshold and measurement process for financial statement recognition and measurement of uncertain tax positions taken or expected to be taken in a tax return, and also provides guidance on the de-recognition of previously recorded benefits and their classification, as well as the proper recording of interest and penalties, accounting in interim periods, disclosures and transition.  The Company periodically reviews its income tax positions based on tax laws and regulations and financial reporting considerations, and records adjustments as appropriate.  This review takes into consideration the status of current taxing authorities’ examinations of the Company’s tax returns, recent positions taken by the taxing authorities on similar transactions, if any, and the overall tax environment.
	As of December 31, 2014, the Company had an insignificant amount of unrecognized tax benefits for uncertain tax positions, none of which would materially affect the effective tax rate if recognized. The Company does not anticipate that the amount of unrecognized tax benefits will significantly increase or decrease in the next twelve months. The Company’s policy is to recognize interest and penalties on unrecognized tax benefits in the income tax expense. The amount of interest and penalties accrued for the years ended December 31, 2014 and 2013 is immaterial. The Company files consolidated income tax returns in Oregon and Idaho and for federal purposes. The Company has tax years 2011–2013 open for tax examination under the statute of limitation provisions of the Internal Revenue Code of 1986 (Code). Tax years 2008–2010 are not open for assessment of additional tax, but remain open for adjustment to the amount of Net Operating Losses (NOLs), credit, and other carryforwards utilized in open years or to be utilized in the future.
Employee Stock Ownership Plan	Employee Stock Ownership Plan: In 1995, the Company established an ESOP and related trust for eligible employees of Banner Bank as of January 1, 1995 and eligible employees of the Banks or Company employed after such date. No ESOP contributions were made for the years ended December 31, 2014, 2013 or 2012. On December 17, 2013, the Company's Board of Directors elected to terminate the ESOP effective January 1, 2014. Termination of the ESOP had no impact on the net equity position of the Company or its current and future operating results.
Share-Based Compensation	Share-Based Compensation:  At December 31, 2014, the Company had the following share-based employee/director compensation plans as approved by the shareholders:  the 1998 Stock Option Plan, and the 2001 Stock Option Plan (collectively, the SOPs), the 2012 Restricted Stock and Incentive Bonus Plan, the 2006 Banner Corporation Long-Term Incentive Plan and the Banner Corporation 2014 Omnibus Incentive Plan.  In addition, in 2011 and 2010, the Company made restricted stock grants to Mark Grescovich, President and CEO of Banner Bank and Banner Corporation, in accordance with his employment agreement.
	The Company has adopted the fair value recognition for recognizing stock compensation expense, using the modified-prospective-transition method.  Under that method, compensation costs are recognized based upon grant date fair value.  This method requires the cash flows resulting from the tax benefits of tax deductions in excess of the compensation cost recognized for those options (excess tax benefits) to be classified as financing cash flows.  The restricted stock grants value shares awarded at their fair value, which is their intrinsic value on the date of the award grant.  The expense of the award grants are accrued ratably over the vesting period from the date of each award. These plans are described more fully in Note 16.
	The Banner Corporation Long-Term Incentive Plan (the Plan) was initiated in June 2006.  The Plan is an account-based type of benefit, the value of which is directly related to changes in the value of the Company’s common stock (the excess of the fair market value of a share of the Company’s common stock on the date of vesting over the fair market value of such share on the date granted) plus, for certain awards, dividends declared on the Company’s common stock and changes in Banner Bank’s average earnings rate.  Awards granted through the Plan are considered stock appreciation rights (SARs) and are included in deferred compensation.  The Company remeasures the fair value of a SAR each reporting period until the award is settled and compensation expense is recognized each reporting period for changes in the SAR’s fair value and vesting.
Comprehensive Income	Comprehensive Income (Loss):  Accounting principles generally require that recognized revenue, expenses, gains and losses be included in net income.  In addition, certain changes in assets and liabilities, such as unrealized gains and losses on available-for-sale securities, are reported as a separate component of the equity section of the Consolidated Statements of Financial Condition, and such items, along with net income, are components of comprehensive income (loss) which is reported in the Consolidated Statements of Comprehensive Income (Loss).
Business Segments	Business Segments:  The Company is managed by legal entity and not by lines of business.  Each of the Banks is a community oriented commercial bank chartered in the State of Washington.  The Banks’ primary business is that of a traditional banking institution, gathering deposits and originating loans for portfolio in its respective primary market areas.  The Banks offer a wide variety of deposit products to their consumer and commercial customers.  Lending activities include the origination of real estate, commercial/agriculture business and consumer loans.  Banner Bank is also an active participant in the secondary market, originating residential loans for sale on both a servicing released and servicing retained basis.  In addition to interest income on loans and investment securities, the Banks receive other income from deposit service charges, loan servicing fees and from the sale of loans and investments.  The performance of the Banks is reviewed by the Company’s executive management and Board of Directors on a monthly basis.  All of the executive officers of the Company are members of Banner Bank’s management team.
	Generally Accepted Accounting Principles establish standards to report information about operating segments in annual financial statements and require reporting of selected information about operating segments in interim reports to stockholders.  The Company has determined that its current business and operations consist of a single business segment.
Reclassification	Reclassification:  Certain reclassifications have been made to the prior years’ consolidated financial statements and/or schedules to conform to the current year’s presentation.  These reclassifications may have affected certain reported amounts and ratios for the prior periods.  These reclassifications had no effect on retained earnings (accumulated deficit) or net income as previously presented and the effect of these reclassifications is considered immaterial.

BASIS_OF_PRESENTATION_AND_SUMM2

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Property and Equipment Useful Lives	The provision for depreciation is based upon the straight-line method applied to individual assets and groups of assets acquired in the same year at rates adequate to charge off the related costs over their estimated useful lives:
	Buildings and leased improvements	10–30 years
	Furniture and equipment	3–10 years

BUSINESS_COMBINATIONS_BUSINESS1

BUSINESS COMBINATIONS BUSINESS COMBINATIONS (Tables)	12 Months Ended
	Dec. 31, 2014
Business Acquisition [Line Items]
Schedule of Components of Business Acquisition	The following table displays the fair value as of the acquisition date for each major class of assets acquired and liabilities assumed (in thousands):
		Fair Value at Acquisition
		20-Jun-14
	Assets:
	Cash	$	127,557
	Loans receivable (contractual amount of $88.3 million)	87,923
	Property and equipment	3,079
	Core deposit intangible	2,372
	Other assets	275
	Total assets	221,206
	Liabilities:
	Deposits	212,085
	Other liabilities	42
	Total liabilities	212,127
	Acquisition bargain purchase gain	$	9,079
Schedule of Acquisition Related Costs	The following table presents the key components of acquisition related costs in connection with the Branch Acquisition, the acquisition of Siuslaw, and the proposed acquisition of AmericanWest for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Years Ended December 31
		2014		2013		2012
	Acquisition-related costs recognized in other operating expenses:
	Non-capitalized equipment and repairs	$	105	$	—	$	—
	Client communications	327		—		—
	Information/computer data services	334		—		—
	Payment and processing expenses	185		—		—
	Professional services	2,953		550		—
	Miscellaneous	421		—		—
		$	4,325	$	550	$	—

CASH_AND_SECURITIES_Tables

CASH AND SECURITIES (Tables)	12 Months Ended
	Dec. 31, 2014
Schedule of Investments [Line Items]
Schedule of Cash and Cash Equivalents	Cash, due from bank and cash equivalents consisted of the following at the dates indicated (in thousands):
		31-Dec
		2014		2013
	Cash on hand and due from banks	$	125,689	$	136,810
	Cash equivalents:
	Short-term cash investments	383		539
		$	126,072	$	137,349
	Federal regulations require depository institutions to maintain certain minimum reserve balances.  Included in cash and demand deposits were required reserves of $33.0 million and $30.0 million at December 31, 2014 and 2013, respectively.
Schedule of Investments	The following table sets forth a summary of Banner’s interest-bearing deposits and securities at the dates indicated (includes securities—trading, available-for-sale and held-to-maturity, all at carrying value) (in thousands):
		31-Dec
		2014		2013
	Interest-bearing deposits included in cash and due from banks	$	54,995	$	67,638
	U.S. Government and agency obligations	33,421		61,327
	Municipal bonds:
	Taxable	29,566		34,216
	Tax exempt	141,853		119,588
	Total municipal bonds	171,419		153,804
	Corporate bonds	25,936		44,154
	Mortgage-backed or related securities:
	One- to four-family residential agency guaranteed	58,825		58,117
	One- to four-family residential other	713		1,051
	Multifamily agency guaranteed	256,272		281,319
	Multifamily other	10,497		10,234
	Total mortgage-backed securities	326,307		350,721
	Asset-backed securities:
	Student Loan Marketing Association (SLMA)	15,629		15,681
	Other asset-backed securities	9,766		9,510
	Total asset-backed securities	25,395		25,191
	Equity securities (excludes FHLB stock)	59		68
	Total securities	582,537		635,265
	FHLB stock	27,036		35,390
		$	664,568	$	738,293
Schedule of Trading Securities	The amortized cost and estimated fair value of securities—trading at December 31, 2014 and 2013 are summarized as follows (dollars in thousands):
		December 31, 2014								December 31, 2013
		Amortized		Fair Value			Percent of			Amortized				Fair Value			Percent of
		Cost					Total			Cost							Total
	U.S. Government and agency obligations	$	1,340	$	1,505		3.7	%		$	1,370			$	1,481		2.4	%
	Municipal bonds:
	Tax exempt	1,405		1,440			3.6			4,969				5,023			8
	Corporate bonds	27,995		19,118			47.5			49,498				35,140			56.2
	Mortgage-backed or related securities:
	One- to four-family residential agency guaranteed	8,077		8,726			21.7			10,483				11,230			18
	Multifamily agency guaranteed	8,649		9,410			23.4			8,816				9,530			15.3
	Total mortgage-backed or related securities	16,726		18,136			45.1			19,299				20,760			33.3
	Equity securities	14		59			0.1			14				68			0.1
		$	47,480	$	40,258		100	%		$	75,150			$	62,472		100	%
Schedule of Available-for-sale Securities	The amortized cost, gross unrealized losses and gains and estimated fair value of securities— available-for-sale at December 31, 2014 and 2013 are summarized as follows (dollars in thousands):
		December 31, 2014
		Amortized Cost		Gross Unrealized Gains			Gross Unrealized Losses				Fair Value				Percent of Total
	U.S. Government and agency obligations	$	29,973	$	8		$	(211	)		$	29,770			7.2	%
	Municipal bonds:
	Taxable	16,565		65			(52		)		16,578				4
	Tax exempt	33,394		125			(69		)		33,450				8.2
	Total municipal bonds	49,959		190			(121		)		50,028				12.2
	Corporate bonds	5,000		18			—				5,018				1.2
	Mortgage-backed or related securities:
	One- to four-family residential agency guaranteed	48,001		758			(240		)		48,519				11.8
	One- to four-family residential other	675		38			—				713				0.2
	Multifamily agency guaranteed	241,800		627			(1,346		)		241,081				58.7
	Multifamily other	10,503		6			(12		)		10,497				2.5
	Total mortgage-backed or related securities	300,979		1,429			(1,598		)		300,810				73.2
	Asset-backed securities:
	SLMA	15,462		167			—				15,629				3.8
	Other asset-backed securities	10,051		—			(285		)		9,766				2.4
	Total asset-backed securities	25,513		167			(285		)		25,395				6.2
		$	411,424	$	1,812		$	(2,215	)		$	411,021			100	%
		December 31, 2013
		Amortized Cost		Gross Unrealized Gains			Gross Unrealized Losses				Fair Value				Percent of Total
	U.S. Government and agency obligations	$	59,178	$	117		$	(635	)		$	58,660			12.5	%
	Municipal bonds:
	Taxable	23,842		100			(278		)		23,664				5
	Tax exempt	29,229		170			(208		)		29,191				6.2
	Total municipal bonds	53,071		270			(486		)		52,855				11.2
	Corporate bonds	7,001		2			(39		)		6,964				1.5
	Mortgage-backed or related securities:
	One- to four-family residential agency guaranteed	47,077		648			(838		)		46,887				10
	One- to four-family residential other	988		63			—				1,051				0.2
	Multifamily agency guaranteed	271,428		402			(3,392		)		268,438				57.1
	Multifamily other	10,604		—			(370		)		10,234				2.2
	Total mortgage-backed or related securities	330,097		1,113			(4,600		)		326,610				69.5
	Asset-backed securities:
	SLMA	15,553		128			—				15,681				3.3
	Other asset-backed securities	10,060		—			(550		)		9,510				2
	Total asset-backed securities	25,613		128			(550		)		25,191				5.3
		$	474,960	$	1,630		$	(6,310	)		$	470,280			100	%
Schedule of Available-for-sale Securities with Continuous Loss Position	At December 31, 2014 and 2013, an aging of unrealized losses and fair value of related securities—available-for-sale was as follows (in thousands):
		December 31, 2014
		Less Than 12 Months					12 Months or More								Total
		Fair Value		Unrealized			Fair Value				Unrealized				Fair Value			Unrealized
				Losses							Losses							Losses
	U.S. Government and agency obligations	$	15,983	$	(58	)	$	9,847			$	(153	)		$	25,830		$	(211	)
	Municipal bonds:
	Taxable	7,247		(23		)	3,461				(29		)		10,708			(52		)
	Tax exempt	9,075		(38		)	3,668				(31		)		12,743			(69		)
	Total municipal bonds	16,322		(61		)	7,129				(60		)		23,451			(121		)
	Mortgage-backed or related securities:
	One- to four-family residential agency guaranteed	6,287		(57		)	11,744				(183		)		18,031			(240		)
	Multifamily agency guaranteed	76,309		(167		)	95,522				(1,179		)		171,831			(1,346		)
	Multifamily other	8,450		(12		)	—				—				8,450			(12		)
	Total mortgage-backed or related securities	91,046		(236		)	107,266				(1,362		)		198,312			(1,598		)
	Asset-backed securities:
	Other asset-backed securities	—		—			9,765				(285		)		9,765			(285		)
		$	123,351	$	(355	)	$	134,007			$	(1,860	)		$	257,358		$	(2,215	)
		December 31, 2013
		Less Than 12 Months					12 Months or More								Total
		Fair Value		Unrealized			Fair Value				Unrealized				Fair Value			Unrealized
				Losses							Losses							Losses
	U.S. Government and agency obligations	$	39,621	$	(633	)	$	998			$	(2	)		$	40,619		$	(635	)
	Municipal bonds:
	Taxable	15,580		(261		)	413				(17		)		15,993			(278		)
	Tax exempt	8,217		(205		)	487				(3		)		8,704			(208		)
	Total municipal bonds	23,797		(466		)	900				(20		)		24,697			(486		)
	Corporate bonds	4,961		(39		)	—				—				4,961			(39		)
	Mortgage-backed or related securities:
	One- to four-family residential agency guaranteed	14,972		(133		)	22,560				(705		)		37,532			(838		)
	Multifamily agency guaranteed	199,407		(3,162		)	10,096				(230		)		209,503			(3,392		)
	Multifamily other	10,234		(370		)	—				—				10,234			(370		)
	Total mortgage-backed or related securities	224,613		(3,665		)	32,656				(935		)		257,269			(4,600		)
	Asset-backed securities:
	Other asset-backed securities	—		—			9,510				(550		)		9,510			(550		)
		$	292,992	$	(4,803	)	$	44,064			$	(1,507	)		$	337,056		$	(6,310	)
Schedule of Held-to-maturity Securities	The amortized cost, gross gains and losses and estimated fair value of securities—held-to-maturity at December 31, 2014 and 2013 are summarized as follows (dollars in thousands):
		December 31, 2014
		Amortized Cost		Gross Unrealized Gains			Gross Unrealized Losses				Fair Value				Percent of Total Amortized Cost
	U.S. Government and agency obligations	$	2,146	$	—		$	(19	)		$	2,127			1.6	%
	Municipal bonds:
	Taxable	12,988		371			(1		)		13,358				9.9
	Tax exempt	106,963		5,948			(47		)		112,864				81.5
	Total municipal bonds	119,951		6,319			(48		)		126,222				91.4
	Corporate bonds	1,800		—			—				1,800				1.4
	Mortgage-backed or related securities:
	One- to four-family residential agency guaranteed	1,580		1			(7		)		1,574				1.2
	Multifamily agency guaranteed	5,781		104			—				5,885				4.4
	Total mortgage-backed or related securities	7,361		105			(7		)		7,459				5.6
		$	131,258	$	6,424		$	(74	)		$	137,608			100	%
		December 31, 2013
		Amortized Cost		Gross Unrealized Gains			Gross Unrealized Losses				Fair Value				Percent of Total Amortized Cost
	U.S. Government and agency obligations	$	1,186	$	—		$	(80	)		$	1,106			1.1	%
	Municipal bonds:
	Taxable	10,552		193			(204		)		10,541				10.3
	Tax exempt	85,374		2,545			(1,299		)		86,620				83.3
	Total municipal bonds	95,926		2,738			(1,503		)		97,161				93.6
	Corporate bonds	2,050		—			—				2,050				2
	Mortgage-backed or related securities:
	Multifamily agency guaranteed	3,351		—			(58		)		3,293				3.3
		$	102,513	$	2,738		$	(1,641	)		$	103,610			100	%
Schedule of Held-to-maturity Securities with Continuous Loss Position	At December 31, 2014 and 2013, an age analysis of unrealized losses and fair value of related securities—held-to-maturity was as follows (in thousands):
		December 31, 2014
		Less Than 12 Months					12 Months or More								Total
		Fair Value		Unrealized			Fair Value				Unrealized				Fair Value			Unrealized
				Losses							Losses							Losses
	U.S. Government and agency obligations	$	—	$	—		$	1,127			$	(19	)		$	1,127		$	(19	)
	Municipal bonds:
	Taxable	724		(1		)	—				—				724			(1		)
	Tax exempt	9,097		(43		)	592				(4		)		9,689			(47		)
	Total municipal bonds	9,821		(44		)	592				(4		)		10,413			(48		)
	Mortgage-backed or related securities:
	One- to four-family residential agency guaranteed	1,018		(7		)	—				—				1,018			(7		)
		$	10,839	$	(51	)	$	1,719			$	(23	)		$	12,558		$	(74	)
		December 31, 2013
		Less Than 12 Months					12 Months or More								Total
		Fair Value		Unrealized			Fair Value				Unrealized				Fair Value			Unrealized
				Losses							Losses							Losses
	U.S. Government and agency obligations	$	1,106	$	(80	)	$	—			$	—			$	1,106		$	(80	)
	Municipal bonds:
	Taxable	3,344		(110		)	2,964				(94		)		6,308			(204		)
	Tax exempt	31,234		(1,282		)	303				(17		)		31,537			(1,299		)
	Total municipal bonds	34,578		(1,392		)	3,267				(111		)		37,845			(1,503		)
	Mortgage-backed or related securities:
	Multifamily agency guaranteed	3,293		(58		)	—				—				3,293			(58		)
		$	38,977	$	(1,530	)	$	3,267			$	(111	)		$	42,244		$	(1,641	)
Schedule of Pledged Financial Instruments, Not Separately Reported	The following table presents, as of December 31, 2014, investment securities which were pledged to secure borrowings, public deposits or other obligations as permitted or required by law (in thousands):
		Carrying Value		Amortized Cost			Fair Value
	Purpose or beneficiary:
	State and local governments public deposits	$	116,273	$	116,242		$	122,130
	Interest rate swap counterparties	11,051		10,648			11,051
	Retail repurchase transaction accounts	98,735		98,435			98,735
	Other	248		248			248
	Total pledged securities	$	226,307	$	225,573		$	232,164
Schedule of Income from Securities	The following table sets forth the composition of interest income from securities and cash equivalents for the periods indicated (in thousands):
		Years Ended December 31
		2014		2013			2012
	Mortgage-backed securities interest	$	5,779	$	5,168		$	4,176
	Other taxable interest income	3,101		3,601			5,087
	Tax-exempt interest income	4,206		3,721			3,577
	FHLB stock—dividend income	34		18			—
	Total interest income from securities and cash equivalents	$	13,120	$	12,508		$	12,840
Trading Securities [Member]
Schedule of Investments [Line Items]
Schedule of Securities by Contractual Maturity Date	The amortized cost and estimated fair value of securities—trading at December 31, 2014 and 2013, by contractual maturity, are shown below (in thousands).  Expected maturities will differ from contractual maturities because some securities may be called or prepaid with or without call or prepayment penalties.
		December 31, 2014					December 31, 2013
		Amortized Cost		Fair Value			Amortized Cost				Fair Value
	Maturing in one year or less	$	1,071	$	1,094		$	260			$	263
	Maturing after one year through five years	6,595		7,097			7,056				7,298
	Maturing after five years through ten years	7,035		7,727			12,602				13,572
	Maturing after ten years through twenty years	11,196		10,083			33,335				27,472
	Maturing after twenty years	21,569		14,198			21,883				13,799
		47,466		40,199			75,136				62,404
	Equity securities	14		59			14				68
		$	47,480	$	40,258		$	75,150			$	62,472
Available-for-sale Securities [Member]
Schedule of Investments [Line Items]
Schedule of Securities by Contractual Maturity Date	The amortized cost and estimated fair value of securities—available-for-sale at December 31, 2014 and 2013, by contractual maturity, are shown below (in thousands).  Expected maturities will differ from contractual maturities because some securities may be called or prepaid with or without call or prepayment penalties.
		December 31, 2014					December 31, 2013
		Amortized Cost		Fair Value			Amortized Cost				Fair Value
	Maturing in one year or less	$	9,334	$	9,364		$	25,136			$	25,256
	Maturing after one year through five years	278,629		277,439			322,493				319,489
	Maturing after five years through ten years	45,425		45,610			58,468				57,782
	Maturing after ten years through twenty years	13,846		13,879			15,535				15,135
	Maturing after twenty years	64,190		64,729			53,328				52,618
		$	411,424	$	411,021		$	474,960			$	470,280
Held-to-maturity Securities [Member]
Schedule of Investments [Line Items]
Schedule of Securities by Contractual Maturity Date	The amortized cost and estimated fair value of securities—held-to-maturity at December 31, 2014 and 2013, by contractual maturity, are shown below (in thousands).  Expected maturities will differ from contractual maturities because some securities may be called or prepaid with or without call or prepayment penalties.
		December 31, 2014					December 31, 2013
		Amortized Cost		Fair Value			Amortized Cost				Fair Value
	Maturing in one year or less	$	767	$	771		$	1,270			$	1,281
	Maturing after one year through five years	14,962		15,184			10,834				11,206
	Maturing after five years through ten years	24,233		24,678			17,948				17,908
	Maturing after ten years through twenty years	76,029		81,361			59,643				60,791
	Maturing after twenty years	15,267		15,614			12,818				12,424
		$	131,258	$	137,608		$	102,513			$	103,610

LOANS_RECEIVABLE_AND_THE_ALLOW1

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Tables)	12 Months Ended
	Dec. 31, 2014
Receivables [Abstract]
Schedule of Loans Receivable, Including Loans Held for Sale	Loans receivable, including loans held for sale, at December 31, 2014 and 2013 are summarized as follows (dollars in thousands):
		December 31, 2014							December 31, 2013
		Amount				Percent of Total			Amount				Percent of Total
	Commercial real estate:
	Owner-occupied	$	546,783			14.3	%		$	502,601			14.7	%
	Investment properties	856,942				22.3			692,457				20.2
	Multifamily real estate	167,524				4.4			137,153				4
	Commercial construction	17,337				0.4			12,168				0.4
	Multifamily construction	60,193				1.6			52,081				1.5
	One- to four-family construction	219,889				5.7			200,864				5.9
	Land and land development:
	Residential	102,435				2.7			75,695				2.2
	Commercial	11,152				0.3			10,450				0.3
	Commercial business	723,964				18.9			682,169				20
	Agricultural business, including secured by farmland	238,499				6.2			228,291				6.7
	One- to four-family residential	539,894				14.1			529,494				15.5
	Consumer:
	Consumer secured by one- to four-family	222,205				5.8			173,188				5.1
	Consumer—other	127,003				3.3			121,834				3.5
	Total loans outstanding	3,833,820				100	%		3,418,445				100	%
	Less allowance for loan losses	(75,907		)					(74,258		)
	Net loans	$	3,757,913						$	3,344,187
	Loan amounts are net of unearned, unamortized loan fees (and costs) of approximately $5.8 million at December 31, 2014 and approximately $8.3 million at December 31, 2013.
Schedule of Loans Receivable by Geographic Location	The Company’s loans by geographic concentration at December 31, 2014 were as follows (dollars in thousands):
		Washington				Oregon				Idaho				Other			Total
	Commercial real estate:
	Owner-occupied	$	383,950			$	86,937			$	56,348			$	19,548		$	546,783
	Investment properties	523,806				124,604				60,053				148,479			856,942
	Multifamily real estate	116,793				35,527				14,759				445			167,524
	Commercial construction	15,599				—				1,738				—			17,337
	Multifamily construction	50,931				8,850				412				—			60,193
	One- to four-family construction	129,499				88,468				1,922				—			219,889
	Land and land development:
	Residential	56,675				44,707				1,053				—			102,435
	Commercial	5,781				2,529				2,842				—			11,152
	Commercial business	397,103				125,235				85,580				116,046			723,964
	Agricultural business, including secured by farmland	119,617				69,843				48,997				42			238,499
	One- to four-family residential	341,944				172,974				24,223				753			539,894
	Consumer:
	Consumer secured by one- to four-family	136,888				69,172				14,984				1,161			222,205
	Consumer—other	79,520				40,803				6,243				437			127,003
	Total loans	$	2,358,106			$	869,649			$	319,154			$	286,911		$	3,833,820
	Percent of total loans	61.5		%		22.7		%		8.3		%		7.5		%	100		%
Schedule of Land and Land Development Loans Receivable by State	The geographic concentrations of land and land development loans by state at December 31, 2014 were as follows (dollars in thousands):
		Washington				Oregon				Idaho				Total
	Residential:
	Acquisition and development	$	28,901			$	24,378			$	916			$	54,195
	Improved land and lots	21,703				17,262				137				39,102
	Unimproved land	6,071				3,067				—				9,138
	Commercial and industrial:
	Improved land and lots	3,750				478				1,783				6,011
	Unimproved land	2,031				2,051				1,059				5,141
	Total land and land development loans	$	62,456			$	47,236			$	3,895			$	113,587
	Percent of land and land development loans	55		%		41.6		%		3.4		%		100		%
Schedule of Adjustable and Fixed Rate Loans by Contractual Maturity Date	At December 31, 2014 and 2013, the maturity and repricing composition of those loans, less undisbursed amounts and deferred fees and origination costs, were as follows (in thousands):
		31-Dec
		2014				2013
	Fixed-rate (term to maturity):
	Maturing in one year or less	$	115,571			$	122,313
	Maturing after one year through three years	184,707				143,322
	Maturing after three years through five years	180,449				187,279
	Maturing after five years through ten years	240,742				209,869
	Maturing after ten years	572,793				439,004
	Total fixed-rate loans	1,294,262				1,101,787
	Adjustable-rate (term to rate adjustment):
	Maturing or repricing in one year or less	1,468,316				1,390,579
	Maturing or repricing after one year through three years	416,433				279,791
	Maturing or repricing after three years through five years	566,371				541,529
	Maturing or repricing after five years through ten years	87,506				99,503
	Maturing or repricing after ten years	932				5,256
	Total adjustable-rate loans	2,539,558				2,316,658
	Total loans	$	3,833,820			$	3,418,445
Schedule of Loans to Related Parties	Such loans had the following balances and activity during the years ended December 31, 2014 and 2013 (in thousands):
		Years Ended December 31
		2014				2013
	Balance at beginning of year	$	15,976			$	12,463
	New loans or advances	38,241				39,921
	Repayments and adjustments	(45,608		)		(36,408		)
	Balance at end of period	$	8,609			$	15,976
Schedule of Impaired Loans and Related Allocated Reserve for Loan Losses	The amount of impaired loans and the related allocated reserve for loan losses at the dates indicated were as follows (in thousands):
		December 31, 2014								December 31, 2013
		Loan Amount				Allocated				Loan Amount				Allocated
						Reserves								Reserves
	Impaired loans:
	Nonaccrual loans
	Commercial real estate:
	Owner-occupied	$	1,365			$	20			$	2,466			$	31
	Investment properties	32				5				3,821				89
	One- to four-family construction	—				—				269				—
	Land and land development:
	Residential	1,275				—				924				6
	Commercial business	537				46				724				104
	Agricultural business, including secured by farmland	1,597				26				—				—
	One- to four-family residential	8,507				35				12,532				250
	Consumer:
	Consumer secured by one- to four-family	838				47				903				13
	Consumer—other	411				—				269				1
	Total nonaccrual loans	14,562				179				21,908				494
	Loans 90 days past due and still accruing
	Agricultural business, including secured by farmland	—				—				105				8
	One- to four-family residential	2,095				10				2,611				16
	Consumer:
	Consumer secured by one- to four-family	80				—				13				—
	Consumer—other	—				—				131				1
	Total loans 90 days past due and still accruing	2,175				10				2,860				25
	Troubled debt restructuring on accrual status:
	Commercial real estate:
	Owner-occupied	184				4				186				4
	Investment properties	6,021				724				5,367				415
	Multifamily real estate	786				86				5,744				1,139
	One- to four-family construction	3,923				640				6,864				1,002
	Land and land development:
	Residential	1,279				346				4,061				754
	Commercial business	739				82				1,299				222
	One- to four-family residential	15,792				987				23,302				1,355
	Consumer:
	Consumer secured by one- to four-family	233				28				360				33
	Consumer—other	197				6				245				34
	Total troubled debt restructurings on accrual status	29,154				2,903				47,428				4,958
	Total impaired loans	$	45,891			$	3,092			$	72,196			$	5,477
	As of December 31, 2014 and 2013, the Company had commitments to advance funds up to an additional amount of $2.1 million and $225,000, respectively, related to TDRs.
Schedule of Impaired Loans With and Without Specific Reserves	The following tables provide additional information on impaired loans with and without specific allowance reserves as of December 31, 2014 and December 31, 2013.  Recorded investment includes the unpaid principal balance or the carrying amount of loans less charge-offs and net deferred loan fees (in thousands):
		At or For the Year Ended December 31, 2014
		Recorded Investment				Unpaid				Related				Average			Interest
						Principal				Allowance				Recorded Investment			Income
						Balance											Recognized
	Without a specific allowance reserve (1)
	Commercial real estate:
	Owner-occupied	$	399			$	449			$	20			$	526		$	—
	Investment properties	32				32				5				44			—
	Commercial business	537				763				46				566			—
	Agricultural business, including secured by farmland	853				853				26				1,122			—
	One- to four-family residential	8,546				9,244				18				7,284			29
	Consumer:
	Consumer secured by one- to four-family	783				888				11				838			3
	Consumer—other	295				305				—				270			—
		11,445				12,534				126				10,650			32
	With a specific allowance reserve (2)
	Commercial real estate:
	Owner-occupied	1,149				1,149				4				1,315			12
	Investment properties	6,022				6,426				724				6,101			315
	Multifamily real estate	786				786				86				795			45
	One- to four-family construction	3,923				3,923				640				2,655			118
	Land and land development:
	Residential	2,554				3,710				346				2,872			89
	Commercial business	739				739				82				762			41
	Agricultural business, including secured by farmland	744				744				—				744			—
	One- to four-family residential	17,848				18,611				1,014				18,809			841
	Consumer:
	Consumer secured by one- to four-family	368				368				64				410			16
	Consumer—other	313				329				6				327			19
		34,446				36,785				2,966				34,790			1,496
	Total
	Commercial real estate:
	Owner occupied	1,548				1,598				24				1,841			12
	Investment properties	6,054				6,458				729				6,145			315
	Multifamily real estate	786				786				86				795			45
	One- to four-family construction	3,923				3,923				640				2,655			118
	Land and land development:
	Residential	2,554				3,710				346				2,872			89
	Commercial business	1,276				1,502				128				1,328			41
	Agricultural business, including secured by farmland	1,597				1,597				26				1,866			—
	One- to four-family residential	26,394				27,855				1,032				26,093			870
	Consumer:
	Consumer secured by one- to four-family	1,151				1,256				75				1,248			19
	Consumer—other	608				634				6				597			19
		$	45,891			$	49,319			$	3,092			$	45,440		$	1,528
		At or For the Year Ended December 31, 2013
		Recorded Investment				Unpaid				Related				Average			Interest
						Principal				Allowance				Recorded Investment			Income
						Balance											Recognized
	Without a specific allowance reserve (1)
	Commercial real estate:
	Owner-occupied	$	534			$	584			$	31			$	569		$	—
	Investment properties	429				974				89				624			—
	Commercial business	724				1,040				104				896			—
	Agricultural business, including secured by farmland	105				105				8				110			8
	One- to four-family residential	8,611				9,229				42				8,889			31
	Consumer:
	Consumer secured by one- to four-family	870				1,013				13				900			1
	Consumer—other	276				285				2				287			8
		11,549				13,230				289				12,275			48
	With a specific allowance reserve (2)
	Commercial real estate:
	Owner-occupied	2,118				2,118				4				2,192			12
Investment properties	8,759				10,395				415				8,353			241
Multifamily real estate	5,744				5,744				1,139				5,705			298
One- to four-family construction	7,133				7,213				1,002				5,870			239
Land and land development:
Residential	4,985				6,140				760				6,053			221
Commercial business	1,298				1,298				222				1,340			59
One- to four-family residential	29,834				31,440				1,579				31,668			1,032
Consumer:
Consumer secured by one- to four-family	406				407				33				503			24
Consumer—other	370				386				34				390			21
	60,647				65,141				5,188				62,074			2,147
Total
Commercial real estate:
Owner-occupied	2,652				2,702				35				2,761			12
Investment properties	9,188				11,369				504				8,977			241
Multifamily real estate	5,744				5,744				1,139				5,705			298
One- to four-family construction	7,133				7,213				1,002				5,870			239
Land and land development:
Residential	4,985				6,140				760				6,053			221
Commercial business	2,022				2,338				326				2,236			59
Agricultural business, including secured by farmland	105				105				8				110			8
One- to four-family residential	38,445				40,669				1,621				40,557			1,063
Consumer:
Consumer secured by one- to four-family	1,276				1,420				46				1,403			25
Consumer—other	646				671				36				677			29
	$	72,196			$	78,371			$	5,477			$	74,349		$	2,195
(1)	Loans without a specific allowance reserve have not been individually evaluated for impairment, but have been included in pools of homogeneous loans for evaluation of related allowance reserves.
(2)	Loans with a specific allowance reserve have been individually evaluated for impairment using either a discounted cash flow analysis or, for collateral dependent loans, current appraisals to establish realizable value. These analyses may identify a specific impairment amount needed or may conclude that no reserve is needed. Any specific impairment that is identified is included in the category’s "Related Allowance" column.
Schedule of Troubled Debt Restructurings	The following tables present TDRs at December 31, 2014 and 2013 (in thousands):
		December 31, 2014
		Accrual				Nonaccrual				Total
		Status				Status				TDRs
	Commercial real estate:
	Owner-occupied	$	183			$	109			$	292
	Investment properties	6,021				32				6,053
	Multifamily real estate	786				—				786
	One- to four-family construction	3,923				—				3,923
	Land and land development:
	Residential	1,279				525				1,804
	Commercial business	739				87				826
	One- to four-family residential	15,793				1,363				17,156
	Consumer:
	Consumer secured by one- to four-family	233				117				350
	Consumer—other	197				116				313
		$	29,154			$	2,349			$	31,503
		December 31, 2013
		Accrual				Nonaccrual				Total
		Status				Status				TDRs
	Commercial real estate:
	Owner-occupied	$	186			$	613			$	799
	Investment properties	5,367				1,630				6,997
	Multifamily real estate	5,744				—				5,744
	One- to four-family construction	6,864				269				7,133
	Land and land development:
	Residential	4,061				174				4,235
	Commercial business	1,299				164				1,463
	One- to four-family residential	23,302				2,474				25,776
	Consumer:
	Consumer secured by one- to four-family	360				252				612
	Consumer—other	245				123				368
		$	47,428			$	5,699			$	53,127
Schedule of Newly Restructured Loans	The following tables present new TDRs that occurred during the years ended December 31, 2014 and 2013 (dollars in thousands):
		Year Ended December 31, 2014
		Number of			Pre-modification Outstanding Recorded Investment				Post-modification Outstanding Recorded Investment
		Contracts
	Recorded Investment (1) (2)
	Commercial real estate:
	Owner-occupied	1			$	203			$	203
	One- to four-family construction	10			2,153				2,153
	Commercial business	1			100				100
	One- to four-family residential	4			905				862
	Consumer - other	1			9				9
		17			$	3,370			$	3,327
		Year Ended December 31, 2013
		Number of			Pre-modification Outstanding Recorded Investment				Post-modification Outstanding Recorded Investment
		Contracts
	Recorded Investment (1) (2)
	Commercial real estate:
	Owner-occupied	1			$	1,246			$	1,246
	Multifamily real estate	1			375				375
	One- to four-family construction	8			3,082				3,082
	Land and land development:
	Residential	2			1,029				1,029
	Commercial business	1			100				100
	One- to four-family residential	10			2,726				2,726
		23			$	8,558			$	8,558
	(1)	Since most loans were already considered classified and/or on non-accrual status prior to restructuring, the modifications did not have a material effect on the Company’s determination of the allowance for loan losses.
	(2)	The majority of these modifications do not fit into one separate type, such as: rate, term, amount, interest-only or payment; but instead are a combination of multiple types of modifications, therefore they are disclosed in aggregate.
Schedule of Troubled Debt Restructurings Which Incurred A Payment Default	The following table presents TDRs which incurred a payment default within the years ended December 31, 2014 and 2013, for which the payment default occurred within twelve months of the restructure date.  A default on a restructured loan results in a transfer to nonaccrual status, a charge-off or a combination of both (in thousands):
		Years Ended December 31
		2014							2013
		Number of Loans			Amount				Number of Loans			Amount
	Construction and land	—			$	—			2			$	483
	Commercial business	—			—				2			321
	One- to four-family residential	—			—				2			222
	Total	—			$	—			6			$	1,026
Schedule of the Portfolio of Risk-Rated Loans and Non-Risk-Rated Loans by Grade or Other Characteristic	The following table shows Banner’s portfolio of risk-rated loans and non-risk-rated loans by grade or other characteristic as of December 31, 2014 (in thousands):
		December 31, 2014
		Commercial				Multifamily				Construction				Commercial Business			Agricultural Business			One- to Four-Family Residential			Consumer			Total Loans
		Real Estate				Real Estate				and Land
	Risk-rated loans:
	Pass (Risk Ratings 1-5) (1)	$	1,375,885			$	166,712			$	395,356			$	691,143		$	234,101		$	527,384		$	346,456		$	3,737,037
	Special mention	3,717				—				—				27,453			1,055			63			140			32,428
	Substandard	24,123				812				15,650				5,368			3,343			12,447			2,601			64,344
	Doubtful	—				—				—				—			—			—			11			11
	Total loans	$	1,403,725			$	167,524			$	411,006			$	723,964		$	238,499		$	539,894		$	349,208		$	3,833,820
	Performing loans	$	1,402,328			$	167,524			$	409,731			$	723,427		$	236,902		$	529,292		$	347,880		$	3,817,084
	Non-performing loans (2)	1,397				—				1,275				537			1,597			10,602			1,328			16,736
	Total loans	$	1,403,725			$	167,524			$	411,006			$	723,964		$	238,499		$	539,894		$	349,208		$	3,833,820
	(1)	The Pass category includes some performing loans that are part of homogenous pools which are not individually risk-rated.  This includes all consumer loans, all one- to four-family residential loans and, as of December 31, 2014, in the commercial business category, $115 million of credit-scored small business loans.  As loans in these pools become non-performing, they are individually risk-rated.
	(2)	Non-performing loans include loans on non-accrual status and loans more than 90 days delinquent, but still accruing interest.
	The following table shows Banner’s portfolio of risk-rated loans and non-risk-rated loans by grade or other characteristic as of December 31, 2013 (in thousands):
		December 31, 2013
		Commercial				Multifamily				Construction				Commercial Business			Agricultural Business			One- to Four-Family Residential			Consumer			Total Loans
		Real Estate				Real Estate				and Land
	Risk-rated loans:
	Pass (Risk Ratings 1-5) (1)	$	1,160,921			$	131,523			$	332,150			$	655,007		$	225,329		$	511,967		$	291,992		$	3,308,889
	Special mention	6,614				—				350				10,484			561			—			106			18,115
	Substandard	26,979				5,630				18,758				16,669			2,401			17,527			2,924			90,888
	Doubtful	544				—				—				9			—			—			—			553
	Total loans	$	1,195,058			$	137,153			$	351,258			$	682,169		$	228,291		$	529,494		$	295,022		$	3,418,445
	Performing loans	$	1,188,771			$	137,153			$	350,065			$	681,445		$	228,187		$	514,351		$	293,705		$	3,393,677
	Non-performing loans (2)	6,287				—				1,193				724			104			15,143			1,317			24,768
	Total loans	$	1,195,058			$	137,153			$	351,258			$	682,169		$	228,291		$	529,494		$	295,022		$	3,418,445
	(1)	The Pass category includes some performing loans that are part of homogenous pools which are not individually risk-rated.  This includes all consumer loans, all one- to four-family residential loans and, as of December 31, 2013, in the commercial business category, $94 million of credit-scored small business loans.  As loans in these pools become non-performing, they are individually risk-rated.
	(2)	Non-performing loans include loans on non-accrual status and loans more than 90 days delinquent, but still accruing interest.
Schedule of the Age Analysis of the Company's Past Due Loans	The following tables provide additional detail on the age analysis of Banner’s past due loans as of December 31, 2014 and 2013 (in thousands):
		December 31, 2014
		30–59 Days Past Due				60–89 Days Past Due				90 Days or More Past Due				Total Past Due			Current			Total Loans			Loans 90 Days or More Past Due and Accruing
	Commercial real estate:
	Owner-occupied	$	—			$	1,984			$	—			$	1,984		$	544,799		$	546,783		$	—
	Investment properties	639				—				—				639			856,303			856,942			—
	Multifamily real estate	—				—				—				—			167,524			167,524			—
	Commercial construction	—				—				—				—			17,337			17,337			—
	Multifamily construction	—				—				—				—			60,193			60,193			—
	One- to four-family construction	840				—				—				840			219,049			219,889			—
	Land and land development:
	Residential	759				—				750				1,509			100,926			102,435			—
	Commercial	—				—				—				—			11,152			11,152			—
	Commercial business	775				35				100				910			723,054			723,964			—
	Agricultural business, including secured by farmland	597				466				744				1,807			236,692			238,499			—
	One- to four-family residential (1)	877				1,623				7,526				10,026			529,868			539,894			2,095
	Consumer:
	Consumer secured by one- to four-family	59				60				139				258			221,947			222,205			80
	Consumer—other	491				88				293				872			126,131			127,003			—
	Total	$	5,037			$	4,256			$	9,552			$	18,845		$	3,814,975		$	3,833,820		$	2,175
		December 31, 2013
		30–59 Days Past Due				60–89 Days Past Due				90 Days or More Past Due				Total Past Due			Current			Total Loans			Loans 90 Days or More Past Due and Accruing
	Commercial real estate:
	Owner-occupied	$	883			$	550			$	813			$	2,246		$	500,355		$	502,601		$	—
	Investment properties	—				—				—				—			692,457			692,457			—
	Multifamily real estate	1,845				785				—				2,630			134,523			137,153			—
	Commercial construction	—				—				—				—			12,168			12,168			—
	Multifamily construction	—				—				—				—			52,081			52,081			—
	One- to four-family construction	9				7				4				20			200,844			200,864			—
	Land and land development:
	Residential	—				—				251				251			75,444			75,695			—
	Commercial	—				—				—				—			10,450			10,450			—
	Commercial business	2,001				2				299				2,302			679,867			682,169			—
	Agricultural business, including secured by farmland	—				—				—				—			228,291			228,291			105
	One- to four-family residential (1)	521				2,550				9,142				12,213			517,281			529,494			2,611
	Consumer:
	Consumer secured by one- to four-family	723				93				918				1,734			171,454			173,188			13
	Consumer—other	384				99				131				614			121,220			121,834			131
	Total	$	6,366			$	4,086			$	11,558			$	22,010		$	3,396,435		$	3,418,445		$	2,860
Schedule of the Allowance for Loan Losses and Loan Balances Individually and Collectively Evaluated for Impairment	The following tables provide additional information on the allowance for loan losses and loan balances individually and collectively evaluated for impairment at or for the year ended December 31, 2014 (in thousands):
		For the Year Ended December 31, 2014
		Commercial				Multifamily				Construction and Land				Commercial Business			Agricultural Business			One- to Four-Family Residential			Consumer			Unallocated			Total
		Real Estate				Real Estate
	Allowance for loan losses:
	Beginning balance	$	16,759			$	5,306			$	17,640			$	11,773		$	2,841		$	11,486		$	1,335		$	7,118		$	74,258
	Provision for loan losses	1,757				(724		)		6,336				626			(417		)	(5,772		)	90			(1,896		)	—
	Recoveries	1,507				—				1,776				988			1,576			618			528			—			6,993
	Charge-offs	(1,239		)		(20		)		(207		)		(1,344		)	(179		)	(885		)	(1,470		)	—			(5,344		)
	Ending balance	$	18,784			$	4,562			$	25,545			$	12,043		$	3,821		$	5,447		$	483		$	5,222		$	75,907
		December 31, 2014
		Commercial				Multifamily				Construction and Land				Commercial Business			Agricultural Business			One- to Four-Family Residential			Consumer			Unallocated			Total
		Real Estate				Real Estate
	Allowance individually evaluated for impairment	$	728			$	86			$	986			$	82		$	—		$	1,014		$	70		$	—		$	2,966
	Allowance collectively evaluated for impairment	18,056				4,476				24,559				11,961			3,821			4,433			413			5,222			72,941
	Total allowance for loan losses	$	18,784			$	4,562			$	25,545			$	12,043		$	3,821		$	5,447		$	483		$	5,222		$	75,907
		December 31, 2014
		Commercial				Multifamily				Construction				Commercial Business			Agricultural Business			One- to Four-Family Residential			Consumer			Unallocated			Total
		Real Estate				Real Estate				and Land
	Loan balances:
	Loans individually evaluated for impairment	$	7,171			$	786			$	6,477			$	739		$	744		$	17,848		$	681		$	—		$	34,446
	Loans collectively evaluated for impairment	1,396,554				166,738				404,529				723,225			237,755			522,046			348,527			—			3,799,374
	Total loans	$	1,403,725			$	167,524			$	411,006			$	723,964		$	238,499		$	539,894		$	349,208		$	—		$	3,833,820
	The following tables provide additional information on the allowance for loan losses and loan balances individually and collectively evaluated for impairment at or for the year ended December 31, 2013 (in thousands):
		For the Year Ended December 31, 2013
		Commercial				Multifamily				Construction				Commercial Business			Agricultural Business			One- to Four-Family Residential			Consumer			Unallocated			Total
		Real Estate				Real Estate				and Land
	Allowance for loan losses:
	Beginning balance	$	15,322			$	4,506			$	14,991			$	9,957		$	2,295		$	16,475		$	1,348		$	11,865		$	76,759
	Provision for loan losses	1,639				800				2,195				1,925			97			(2,995		)	1,086			(4,747		)	—
	Recoveries	2,367				—				2,275				1,673			697			145			340			—			7,497
	Charge-offs	(2,569		)		—				(1,821		)		(1,782		)	(248		)	(2,139		)	(1,439		)	—			(9,998		)
	Ending balance	$	16,759			$	5,306			$	17,640			$	11,773		$	2,841		$	11,486		$	1,335		$	7,118		$	74,258
		December 31, 2013
		Commercial				Multifamily				Construction				Commercial Business			Agricultural Business			One- to Four-Family Residential			Consumer			Unallocated			Total
		Real Estate				Real Estate				and Land
	Allowance individually evaluated for impairment	$	419			$	1,139			$	1,762			$	222		$	—		$	1,579		$	67		$	—		$	5,188
	Allowance collectively evaluated for impairment	16,340				4,167				15,878				11,551			2,841			9,907			1,268			7,118			69,070
	Total allowance for loan losses	$	16,759			$	5,306			$	17,640			$	11,773		$	2,841		$	11,486		$	1,335		$	7,118		$	74,258
		December 31, 2013
		Commercial				Multifamily				Construction				Commercial Business			Agricultural Business			One- to Four-Family Residential			Consumer			Unallocated			Total
		Real Estate				Real Estate				and Land
	Loan balances:
	Loans individually evaluated for impairment	$	10,877			$	5,744			$	12,118			$	1,298		$	—		$	29,834		$	776		$	—		$	60,647
	Loans collectively evaluated for impairment	1,184,181				131,409				339,140				680,871			228,291			499,660			294,246			—			3,357,798
	Total loans	$	1,195,058			$	137,153			$	351,258			$	682,169		$	228,291		$	529,494		$	295,022		$	—		$	3,418,445

REAL_ESTATE_OWNED_HELD_FOR_SAL1

REAL ESTATE OWNED, HELD FOR SALE, NET (Tables)	12 Months Ended
	Dec. 31, 2014
Real Estate [Abstract]
Schedule of Changes in Real Estate Owned, Net of Valuation Allowance	The following table presents the changes in real estate owned (REO), net of valuation allowance, for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Years Ended December 31
		2014			2013			2012
	Balance, beginning of period	$	4,044		$	15,778		$	42,965
	Additions from loan foreclosures	3,264			3,166			13,930
	Additions from capitalized costs	30			348			300
	Proceeds from dispositions of REO	(4,923		)	(16,944		)	(40,965		)
	Gain on sale of REO	973			2,481			4,725
	Valuation adjustments in the period	(36		)	(785		)	(5,177		)
	Balance, end of period	$	3,352		$	4,044		$	15,778
Schedule of Real Estate Owned by Type and Geographic Location by State	The following table shows REO by type and geographic location by state as of December 31, 2014 (dollars in thousands):
		Washington			Oregon			Idaho			Total
	Land development—residential	259			1,271			32			1,562
	One- to four-family real estate	1,435			355			—			1,790
	Total REO	$	1,694		$	1,626		$	32		$	3,352
	Percent of total REO	50.5		%	48.5		%	1		%	100		%

PROPERTY_AND_EQUIPMENT_NET_Tab

PROPERTY AND EQUIPMENT, NET (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Land, buildings and equipment owned by the Company and its subsidiaries at December 31, 2014 and 2013 are summarized as follows (in thousands):
		31-Dec
		2014			2013
	Land	$	21,969		$	19,974
	Buildings and leasehold improvements	98,901			99,351
	Furniture and equipment	72,152			65,912
		193,022			185,237
	Less accumulated depreciation	(101,837		)	(94,970		)
	Property and equipment, net	$	91,185		$	90,267
Schedule of Future Minimum Rental Payments for Operating Leases	The Company’s obligations under long-term property leases are as follows:
	Year		Amount
	2015		$ 7.6 million
	2016		5.7 million
	2017		4.7 million
	2018		4.2 million
	2019		3.4 million
	Thereafter		9.6 million
	Total		$ 35.2 million

DEPOSITS_Tables

DEPOSITS (Tables)	12 Months Ended
	Dec. 31, 2014
Banking and Thrift [Abstract]
Schedule of Deposit Liabilities	Deposits consist of the following at December 31, 2014 and 2013 (dollars in thousands):
		31-Dec
		2014				2013
		Amount		Percent of		Amount			Percent of
				Total					Total
	Non-interest-bearing checking	$	1,298,866	33.3	%	$	1,115,346		30.8	%
	Interest-bearing checking	439,480		11.3		422,910			11.7
	Regular savings accounts	901,142		23.1		798,764			22.1
	Money market accounts	488,946		12.5		408,211			11.3
	Total transaction and savings accounts	3,128,434		80.2		2,745,231			75.9
	Certificates of deposit:
	Up to 1.00%	643,065		16.5		723,891			20
	1.01% to 2.00%	87,661		2.3		95,663			2.6
	2.01% to 3.00%	32,184		0.8		43,062			1.2
	3.01% to 4.00%	3,024		0.1		6,663			0.2
	4.01% and greater	4,582		0.1		3,416			0.1
	Total certificates of deposit	770,516		19.8		872,695			24.1
	Total deposits	$	3,898,950	100	%	$	3,617,926		100	%
	Included in total deposits:
	Public fund transaction accounts	$	102,854	2.6	%	$	87,521		2.4	%
	Public fund interest-bearing certificates	35,346		0.9		51,465			1.4
	Total public deposits	$	138,200	3.5	%	$	138,986		3.8	%
	Total brokered deposits	$	4,799	0.1	%	$	4,291		0.1	%
	Deposits at December 31, 2014 and 2013 included deposits from the Company’s directors, executive officers and related entities totaling $6.2 million and $6.7 million, respectively.
Schedule of Certificate Accounts by Total Balance	Certificate of deposit accounts by total balance at December 31, 2014 and 2013 were as follows (in thousands):
		31-Dec
		2014		2013
	Certificates of deposit less than $100,000	$	358,189	$	386,745
	Certificates of deposit $100,000 through $250,000	275,156		308,130
	Certificates of deposit more than $250,000	137,171		177,820
	Total certificates of deposit	$	770,516	$	872,695
	Certificates of deposit of $250,000 and greater totaled $141 million and $184 million at December 31, 2014 and 2013, respectively.
Schedule Maturities and Weighted Average Interest Rates of Certificates of Deposit	Scheduled maturities and weighted average interest rates of certificate accounts at December 31, 2014 and 2013 are as follows (dollars in thousands):
		31-Dec
		2014				2013
		Amount		Weighted		Amount			Weighted
				Average Rate					Average Rate
	Maturing in one year or less	$	564,501	0.46	%	$	660,394		0.47	%
	Maturing after one year through two years	117,724		0.89		117,789			1.05
	Maturing after two years through three years	46,378		1.19		47,362			1.34
	Maturing after three years through four years	20,016		1.42		26,443			1.56
	Maturing after four years through five years	17,338		1.22		17,075			1.34
	Maturing after five years	4,559		2.09		3,632			1.78
	Total certificates of deposit	$	770,516	1.06	%	$	872,695		0.65	%
Schedule of Deposit Liabilities Activities	The following table sets forth the deposit activities for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Years Ended December 31
		2014		2013			2012
	Balance at beginning of year	$	3,617,926	$	3,557,804		$	3,475,654
	Net increase before interest credited	273,446		50,385			67,043
	Interest credited	7,578		9,737			15,107
	Net increase in deposits	281,024		60,122			82,150
	Balance at end of year	$	3,898,950	$	3,617,926		$	3,557,804
Schedule of Interest Expense Deposit Liabilities by Type	Deposit interest expense by type for the years ended December 31, 2014, 2013 and 2012 was as follows (in thousands):
		Years Ended December 31
		2014		2013			2012
	Certificates of deposit (1)	$	5,145	$	6,836		$	11,458
	Demand, interest-bearing checking and money market accounts	1,123		1,329			1,824
	Regular savings	1,310		1,572			1,825
		$	7,578	$	9,737		$	15,107
	(1)	Interest expense on certificate of deposit accounts with balances of $100,000 or more totaled $3.1 million, $4.0 million, and $6.7 million for the years ended December 31, 2014, 2013 and 2012, respectively.

ADVANCES_FROM_FEDERAL_HOME_LOA1

ADVANCES FROM FEDERAL HOME LOAN BANK OF SEATTLE (Tables)	12 Months Ended
	Dec. 31, 2014
Advances from Federal Home Loan Banks [Abstract]
Schedule of Federal Home Loan Bank Advances, Fiscal Year Maturity	At December 31, 2014 and 2013, FHLB advances were scheduled to mature as follows (dollars in thousands):
		31-Dec
		2014						2013
		Amount			Weighted Average Rate			Amount				Weighted Average Rate
	Maturing in one year or less	$	32,000		0.27	%		$	27,000			0.23	%
	Maturing after one year through three years	—			—			—				—
	Maturing after three years through five years	—			—			—				—
	Maturing after five years	196			5.94			203				5.94
	Total FHLB advances, at par	32,196			0.27			27,203				0.27
	Fair value adjustment	54						47
	Total FHLB advances, carried at fair value	$	32,250					$	27,250
Schedule of Federal Home Loan Bank Advances, Activity for Year	The maximum, average outstanding and year-end balances (excluding fair value adjustments) and average interest rates on advances from the FHLB were as follows at or for the years ended December 31, 2014, 2013 and 2012 (dollars in thousands):
		At or For the Years Ended December 31
		2014			2013				2012
	Maximum outstanding at any month end, at par	$	105,450		$	60,377			$	10,216
	Average outstanding, at par	39,121			18,935				10,215
	Year-end outstanding, at par	32,196			27,203				10,210
	Weighted average interest rates:
	Annual	0.32		%	0.52		%		2.49		%
	End of period	0.27		%	0.27		%		2.45		%
	Interest expense during the period	$	125		$	99			$	254

OTHER_BORROWINGS_Tables

OTHER BORROWINGS (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Schedule of Other Borrowings, Maturity	A summary of all other borrowings at December 31, 2014 and 2013 by the period remaining to maturity is as follows (dollars in thousands):
		At or for the Years Ended December 31
		2014				2013
		Amount		Weighted		Amount			Weighted
				Average Rate					Average Rate
	Retail repurchase agreements:
	Maturing in one year or less	$	77,185	0.2	%	$	83,056		0.2	%
	Maturing after one year through two years	—		—		—			—
	Maturing after two years	—		—		—			—
	Total year-end outstanding	$	77,185	0.2		$	83,056		0.2
	Average outstanding	$	83,965	0.2		$	84,877		0.23
	Maximum outstanding at any month-end	89,921		n/a		91,964			n/a
Schedule of Interest Expense for Other Borrowings	The table below summarizes interest expense for other borrowings for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Years Ended December 31
		2014		2013			2012
	Retail repurchase agreements	$	172	$	192		$	281
	FDIC guaranteed debt	—		—			477
	Total expense	$	172	$	192		$	758

JUNIOR_SUBORDINATED_DEBENTURES1

JUNIOR SUBORDINATED DEBENTURES AND MANDATORILY REDEEMABLE TRUST PREFERRED SECURITIES (Tables)	12 Months Ended
	Dec. 31, 2014
Other Liabilities Disclosure [Abstract]
Schedule of Trust Preferred Securities	The following table is a summary of trust preferred securities at December 31, 2014 (dollars in thousands):
	Name of Trust	Aggregate Liquidation Amount of Trust Preferred Securities		Aggregate Liquidation Amount of Common Capital Securities		Aggregate Principal Amount of Junior Subordinated Debentures			Stated Maturity	Current Interest Rate		Reset Period	Interest Rate Spread	Interest Deferral Period	Redemption Option
	Banner Capital Trust II	$	15,000	$	464	$	15,464		2033	3.58	%	Quarterly	Three-month	20 Consecutive	On or after
													LIBOR + 3.35%	Quarters	7-Jan-08
	Banner Capital Trust III	15,000		465		15,465			2033	3.13		Quarterly	Three-month	20 Consecutive	On or after
													LIBOR + 2.90%	Quarters	8-Oct-08
	Banner Capital Trust IV	15,000		465		15,465			2034	3.08		Quarterly	Three-month	20 Consecutive	On or after
													LIBOR + 2.85%	Quarters	7-Apr-09
	Banner Capital Trust V	25,000		774		25,774			2035	1.8		Quarterly	Three-month	20 Consecutive	On or after
													LIBOR + 1.57%	Quarters	23-Nov-10
	Banner Capital Trust VI	25,000		774		25,774			2037	1.86		Quarterly	Three-month	20 Consecutive	On or after
													LIBOR + 1.62%	Quarters	1-Mar-12
	Banner Capital Trust VII	25,000		774		25,774			2037	1.62		Quarterly	Three-month	20 Consecutive	On or after
													LIBOR + 1.38%	Quarters	31-Jul-12
	Total TPS liability at par	$	120,000	$	3,716	123,716				2.32	%
	Fair value adjustment					(45,715		)
	Total TPS liability at fair value					$	78,001

INCOME_TAXES_Tables

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	The following table presents the components of the provision for income tax (benefit) expense included in the Consolidated Statement of Operations for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Years Ended December 31
		2014				2013				2012
	Current	$	24,855			$	12,121			$	10,759
	Deferred	1,365				10,407				841
	Increase (decrease) in valuation allowance	—				—				(36,385		)
	Provision for (benefit from) income taxes	$	26,220			$	22,528			$	(24,785	)
Schedule of Effective Income Tax Rate Reconciliation	The following tables present the reconciliation of the provision for income taxes computed at the federal statutory rate to the actual effective rate for the years ended December 31, 2014, 2013 and 2012 (dollars in thousands):
		Years Ended December 31
		2014				2013				2012
	Provision for (benefit from) income taxes computed at federal statutory rate	$	28,134			$	24,179			$	14,034
	Increase (decrease) in taxes due to:
	Tax-exempt interest	(2,084		)		(1,633		)		(1,710		)
	Investment in life insurance	(626		)		(707		)		(894		)
	State income taxes (benefit), net of federal tax offset	916				824				539
	Tax credits	(661		)		(636		)		(788		)
	Valuation allowance	—				—				(36,385		)
	Other	541				501				419
	Provision for (benefit from) income taxes	$	26,220			$	22,528			$	(24,785	)
		Years Ended December 31
		2014			2013			2012
	Federal income tax statutory rate	35	%		35	%		35	%
	Increase (decrease) in tax rate due to:
	Tax-exempt interest	(2.6	)		(2.4	)		(4.3	)
	Investment in life insurance	(0.8	)		(1.0	)		(2.2	)
	State income taxes (benefit), net of federal tax offset	1.1			1.2			1.3
	Tax credits	(0.8	)		(0.9	)		(2.0	)
	Valuation allowance	—			—			(90.7	)
	Other	0.7			0.7			1.1
	Effective income tax rate	32.6	%		32.6	%		(61.8	)%
Schedule of Net Deferred Tax Asset	The following table reflects the effect of temporary differences that gave rise to the components of the net deferred tax asset as of December 31, 2014 and 2013 (in thousands):
		31-Dec
		2014				2013
	Deferred tax assets:
	REO and loan loss reserves	$	26,536			$	17,326
	Deferred compensation	9,223				7,305
	Net operating loss carryforward	17,577				27,639
	Low income housing tax credits	3,676				3,676
	State net operating losses	1,009				957
	Other	1,344				1,235
	Total deferred tax assets	59,365				58,138
	Deferred tax liabilities:
	FHLB stock dividends	(4,805		)		(5,875		)
	Depreciation	(4,479		)		(4,074		)
	Deferred loan fees, servicing rights and loan origination costs	(7,843		)		(6,444		)
	Intangibles	(975		)		(833		)
	Financial instruments accounted for under fair value accounting	(15,611		)		(15,118		)
	Loan discount	(1,190		)		—
	Total deferred tax liabilities	(34,903		)		(32,344		)
	Deferred income tax asset	24,462				25,794
	Unrealized loss on securities—available-for-sale	145				1,685
	Deferred tax asset, net	$	24,607			$	27,479

STOCKBASED_COMPENSATION_PLANS_

STOCK-BASED COMPENSATION PLANS (Tables)	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Unvested Restricted Stock	A summary of the Company's Restricted Stock award activity during the years ended December 31, 2012, 2013 and 2014 follows:
		Shares			Weighted Average
					Grant-Date
					Fair Value
	Unvested at December 31, 2011	28,735			$	14.5
	Granted	92,035			21.77
	Vested	(11,419	)		14.6
	Forfeited	(1,500	)		21.94
	Unvested at December 31, 2012	107,851			20.59
	Granted	98,891			30.81
	Vested	(42,250	)		19.85
	Forfeited	—			—
	Unvested at December 31, 2013	164,492			26.94
	Granted	90,181			40.07
	Vested	(56,307	)		24.81
	Forfeited	(3,260	)		31
	Unvested at December 31, 2014	195,106			32.83
Schedule of Stock Option Award Activity	A summary of the Company’s stock option award activity for the years ended December 31, 2012, 2013 and 2014 follows:
		Shares			Weighted			Weighted		Aggregate
					Average			Average		Intrinsic Value
					Exercise Price			Remaining
								Contractual
								Term, In Years
	Outstanding at December 31, 2011	51,729			$	168.98		2.4		n/a
	Granted	—			—
	Exercised	—			—
	Forfeited	(9,208	)		145.97
	Outstanding at December 31, 2012	42,521			173.98			1.75		n/a
	Granted	—			—
	Exercised	—			—
	Forfeited	(16,157	)		121.29
	Outstanding at December 31, 2013	26,364			206.27			1.58		n/a
	Granted	—			—
	Exercised	—			—
	Forfeited	(15,700	)		206.44
	Outstanding at December 31, 2014	10,664			206.03			1.9		n/a
	Outstanding at December 31, 2014, net of expected forfeitures	—			—			n/a		n/a
	Exercisable at December 31, 2014	10,664			206.03			1.9
Schedule of Financial Data Pertaining to Outstanding Stock Options, by Exercise Price Range	At December 31, 2014, financial data pertaining to outstanding stock options was as follows:
	Exercise Price		Weighted Average Exercise Price of Option Shares Granted				Number of Option Shares Granted		Weighted Average Option Shares Vested and Exercisable			Weighted Average Exercise Price of Option Shares Exercisable		Remaining Contractual Life
	$0.00 to $184.00		$	176.72			2,593		2,593			$	176.72	0.1 years
	$184.01 to $220.00		212.96				8,071		8,071			212.96		1.8 years
			206.44				10,664		10,664			206.27
Schedule of Stock-based Compensation Costs	The following are the stock-option compensation costs recognized in the Company’s consolidated statements of operations for the years ended December 31, 2014, 2013 and 2012 (in thousands):
		Years Ended December 31
		2014				2013			2012
	Salary and employee benefits	$	—			$	—		$	11
	Decrease in provision for income taxes	—				—			(4		)
	Decrease in equity, net	$	—			$	—		$	7

REGULATORY_CAPITAL_REQUIREMENT1

REGULATORY CAPITAL REQUIREMENTS (Tables)	12 Months Ended
	Dec. 31, 2014
Regulatory Capital Requirements [Abstract]
Schedule of the Regulatory Capital Ratios and Minimum Regulatory Requirements	The following table shows the regulatory capital ratios of the Company and the Banks and the minimum regulatory requirements (dollars in thousands):
		Actual				Minimum for Capital Adequacy Purposes				Minimum to be Categorized as “Well-Capitalized” Under Prompt Corrective Action Provisions
		Amount		Ratio		Amount		Ratio		Amount		Ratio
	December 31, 2014:
	The Company—consolidated:
	Total capital to risk-weighted assets	$	684,583	16.8	%	$	326,071	8	%	n/a		n/a
	Tier 1 capital to risk-weighted assets	633,317		15.54		163,036		4		n/a		n/a
	Tier 1 leverage capital to average assets	633,317		13.41		188,885		4		n/a		n/a
	Banner Bank:
	Total capital to risk- weighted assets	605,997		15.53		312,220		8		$	390,274	10	%
	Tier 1 capital to risk- weighted assets	556,897		14.27		156,110		4		234,165		6
	Tier 1 leverage capital to average assets	556,897		12.42		179,304		4		224,130		5
	Islanders Bank:
	Total capital to risk- weighted assets	36,590		19.92		14,693		8		18,367		10
	Tier 1 capital to risk- weighted assets	34,332		18.69		7,347		4		11,020		6
	Tier 1 leverage capital to average assets	34,332		13.68		10,040		4		12,550		5
	December 31, 2013:
	The Company—consolidated:
	Total capital to risk-weighted assets	$	631,674	16.99	%	$	297,493	8	%	n/a		n/a
	Tier 1 capital to risk-weighted assets	584,838		15.73		148,747		4		n/a		n/a
	Tier 1 leverage capital to average assets	584,838		13.64		171,553		4		n/a		n/a
	Banner Bank:
	Total capital to risk- weighted assets	557,253		15.75		282,984		8		$	353,730	10	%
	Tier 1 capital to risk- weighted assets	512,689		14.49		141,192		4		212,238		6
	Tier 1 leverage capital to average assets	512,689		12.65		162,174		4		202,707		5
	Islanders Bank:
	Total capital to risk- weighted assets	34,795		18.73		14,859		8		18,574		10
	Tier 1 capital to risk- weighted assets	32,469		17.48		7,430		4		11,144		6
	Tier 1 leverage capital to average assets	32,469		13.6		9,553		4		11,941		5

OTHER_INTANGIBLE_ASSETS_AND_MO1

OTHER INTANGIBLE ASSETS AND MORTGAGE SERVICING RIGHTS (Tables)	12 Months Ended
	Dec. 31, 2014
Other Intangible Assets and Mortgage Servicing Rights [Abstract]
Schedule of Changes in Intangible Assets	The following table summarizes the changes in the Company’s CDI and other intangibles for the years ended December 31, 2012, 2013 and 2014 (in thousands):
		CDI			Other			Total
	Balance, December 31, 2011	$	6,322		$	9		$	6,331
	Amortization	(2,092		)	(9		)	(2,101		)
	Balance, December 31, 2012	4,230			—			4,230
	Additions through acquisition	160			—			160
	Amortization	(1,941		)	—			(1,941		)
	Balance, December 31, 2013	2,449			—			2,449
	Additions through acquisition	2,372			—			2,372
	Amortization	(1,990		)	—			(1,990		)
	Balance, December 31, 2014	$	2,831		$	—		$	2,831
Schedule of Estimated Annual Amortization Expense	Estimated amortization expense in future years with respect to existing intangibles as of December 31, 2014 (in thousands):
	Year Ended:	CDI
	December 31, 2015	$	1,007
	December 31, 2016	353
	December 31, 2017	321
	December 31, 2018	296
	Thereafter	854
	Net carrying amount	$	2,831
Schedule of Mortgage Servicing Rights at Amortized Value	An analysis of the mortgage servicing rights for the years ended December 31, 2014, 2013 and 2012 is presented below (in thousands):
		Years Ended December 31
		2014			2013			2012
	Balance, beginning of the year	$	8,086		$	6,244		$	5,584
	Amounts capitalized	3,023			2,913			3,662
	Amortization (1)	(2,079		)	(2,371		)	(2,602		)
	Valuation adjustments in the period	—			1,300			(400		)
	Balance, end of the year (2)	$	9,030		$	8,086		$	6,244
	(1)	Amortization of mortgage servicing rights is recorded as a reduction of loan servicing income and any unamortized balance is fully written off if the loan repays in full.
	(2)	Balances as of December 31, 2014 and 2013 are net of no valuation allowances, and as of December 31, 2012 are net of a $1.3 million valuation allowance.

FAIR_VALUE_OF_FINANCIAL_INSTRU1

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following tables present financial assets and liabilities measured at fair value on a recurring basis and the level within the fair value hierarchy of the fair value measurements for those assets and liabilities as of December 31, 2014 and 2013 (in thousands):
		December 31, 2014
		Level 1				Level 2			Level 3		Total
	Assets:
	Securities—available-for-sale
	U.S. Government and agency	$	—			$	29,770		$	—	$	29,770
	Municipal bonds	—				50,028			—		50,028
	Corporate bonds	—				5,018			—		5,018
	Mortgage-backed securities	—				300,810			—		300,810
	Asset-backed securities	—				25,395			—		25,395
		—				411,021			—		411,021
	Securities—trading
	U.S. Government and agency	—				1,505			—		1,505
	Municipal bonds	—				1,440			—		1,440
	TPS and TRUP CDOs	—				—			19,118		19,118
	Mortgage-backed securities	—				18,136			—		18,136
	Equity securities and other	—				59			—		59
		—				21,140			19,118		40,258
	Derivatives
	Interest rate lock commitments	—				—			317		317
	Interest rate swaps	—				6,290			—		6,290
		$	—			$	438,451		$	19,435	$	457,886
	Liabilities
	Advances from FHLB at fair value	$	—			$	32,250		$	—	$	32,250
	Junior subordinated debentures net of unamortized deferred issuance costs at fair value	—				—			78,001		78,001
	Derivatives
	Interest rate forward sales commitments	—				198			—		198
	Interest rate swaps	—				6,290			—		6,290
		$	—			$	38,738		$	78,001	$	116,739
		December 31, 2013
		Level 1				Level 2			Level 3		Total
	Assets:
	Securities—available-for-sale
	U.S. Government and agency	$	—			$	58,660		$	—	$	58,660
	Municipal bonds	—				52,855			—		52,855
	Corporate bonds	—				6,964			—		6,964
	Mortgage-backed securities	—				326,610			—		326,610
	Asset-backed securities	—				25,191			—		25,191
		—				470,280			—		470,280
	Securities—trading
	U.S. Government and agency	—				1,481			—		1,481
	Municipal bonds	—				5,023			—		5,023
	TPS and TRUP CDOs	—				—			35,140		35,140
	Mortgage-backed securities	—				20,760			—		20,760
	Equity securities and other	—				68			—		68
		—				27,332			35,140		62,472
	Derivatives
	Interest rate lock commitments	—				—			130		130
	Interest rate swaps	—				4,946			—		4,946
		$	—			$	502,558		$	35,270	$	537,828
	Liabilities
	Advances from FHLB at fair value	$	—			$	27,250		$	—	$	27,250
	Junior subordinated debentures net of unamortized deferred issuance costs at fair value	—				—			73,928		73,928
	Derivatives
	Interest rate forward sales commitments	—				43			—		43
	Interest rate swaps	—				4,946			—		4,946
		$	—			$	32,239		$	73,928	$	106,167
Schedule of Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	The following table provides a reconciliation of the assets and liabilities measured at fair value using significant unobservable inputs (Level 3) on a recurring basis during the year ended December 31, 2014 and 2013 (in thousands):
		Year Ended December 31, 2014
		Level 3 Fair Value Inputs
		TPS and TRUP				Borrowings—
		CDOs				Junior Subordinated
						Debentures
	Beginning balance at December 31, 2013	$	35,140			$	73,928
	Total gains or losses recognized
	Assets gains (losses)	5,481				—
	Liabilities (gains) losses	—				4,073
	Purchases, issuances and settlements	—				—
	Paydowns and maturities	(21,502		)		—
	Transfers in and/or out of Level 3	—				—
	Ending balance at December 31, 2014	$	19,119			$	78,001
		Year Ended December 31, 2013
		Level 3 Fair Value Inputs
		TPS and TRUP				Borrowings—
		CDOs				Junior Subordinated
						Debentures
	Beginning balance at December 31, 2012	$	35,741			$	73,063
	Total gains or losses recognized
	Assets gains (losses)	(181		)		—
	Liabilities (gains) losses	—				865
	Purchases, issuances and settlements	—				—
	Paydowns and maturities	(420		)		—
	Transfers in and/or out of Level 3	—				—
	Ending balance at December 31, 2013	$	35,140			$	73,928
Schedule of Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis	The following tables present financial assets and liabilities measured at fair value on a non-recurring basis and the level within the fair value hierarchy at December 31, 2014 and 2013 (in thousands):
		At or For the Year Ended December 31, 2014
		Level 1				Level 2			Level 3		Total		Net Losses Recognized During the Period
	Impaired loans	$	—			$	—		$	4,725	$	4,725	$	(512	)
	REO	—				—			3,352		3,352		(453		)
		At or For the Year Ended December 31, 2013
		Level 1				Level 2			Level 3		Total		Net Losses Recognized During the Period
	Impaired loans	$	—			$	—		$	10,627	$	10,627	$	(4,890	)
	REO	—				—			4,044		4,044		(853		)
Schedule of Valuation Technique, Unobservable Input, and Qualitative Information for Unobservable Inputs	The following table provides a description of the valuation technique, unobservable inputs, and qualitative information about the unobservable inputs for the Company's assets and liabilities classified as Level 3 and measured at fair value on a recurring and nonrecurring basis at December 31, 2014 and 2013:
							31-Dec
							2014		2013
	Financial Instruments		Valuation Technique		Unobservable Inputs		Weighted Average Rate		Weighted Average Rate
	TPS securities		Discounted cash flows		Discount rate		5.26	%	5.5	%
	TRUP CDOs		Discounted cash flows		Discount rate		3.96		3.85
	Junior subordinated debentures		Discounted cash flows		Discount rate		5.26		5.5
	Impaired loans		Discounted cash flows		Discount rate		Various		Various
			Collateral Valuations		Market values		n/a		n/a
	REO		Appraisals		Market values		n/a		n/a
Schedule of Fair Value of Financial Instruments, by Balance Sheet Grouping	The following table presents estimated fair values of the Company’s financial instruments as of December 31, 2014 and 2013, whether or not recognized or recorded in the consolidated Statements of Financial Condition.  The estimated fair value amounts have been determined by the Company using available market information and appropriate valuation methodologies.  However, considerable judgment is necessary to interpret market data in the development of the estimates of fair value.  Accordingly, the estimates presented herein are not necessarily indicative of the amounts the Company could realize in a current market exchange.  The use of different market assumptions and/or estimation methodologies may have a material effect on the estimated fair value amounts.  The carrying value and estimated fair value of financial instruments at December 31, 2014 and 2013 are as follows (in thousands):
		December 31, 2014							December 31, 2013
		Carrying				Estimated			Carrying		Estimated
		Value				Fair Value			Value		Fair Value
	Assets:
	Cash and due from banks	$	126,072			$	126,072		$	137,349	$	137,349
	Securities—trading	40,258				40,258			62,472		62,472
	Securities—available-for-sale	411,021				411,021			470,280		470,280
	Securities—held-to-maturity	131,258				137,608			102,513		103,610
	Loans receivable held for sale	2,786				2,807			2,734		2,751
	Loans receivable	3,831,034				3,722,179			3,415,711		3,297,936
	FHLB stock	27,036				27,036			35,390		35,390
	BOLI	63,759				63,759			61,945		61,945
	Mortgage servicing rights	9,030				12,987			8,086		11,529
	Derivatives:
	Interest rate swaps	6,290				6,290			4,946		4,946
	Interest rate lock commitments	317				317			130		130
	Liabilities:
	Demand, interest-bearing checking and money market	2,227,292				1,998,649			1,946,467		1,697,095
	Regular savings	901,142				784,006			798,764		695,863
	Certificates of deposit	770,516				764,549			872,695		867,904
	Advances from FHLB at fair value	32,250				32,250			27,250		27,250
	Junior subordinated debentures at fair value	78,001				78,001			73,928		73,928
	Other borrowings	77,185				77,185			83,056		83,056
	Derivatives:
	Interest rate swaps	6,290				6,290			4,946		4,946
	Interest rate forward sales commitments	198				198			43		43

BANNER_CORPORATION_PARENT_COMP1

BANNER CORPORATION (PARENT COMPANY ONLY) (Tables)	12 Months Ended
	Dec. 31, 2014
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Schedule of Condensed Financial Condition	Summary financial information is as follows (in thousands):
	Statements of Financial Condition	31-Dec
		2014			2013
	ASSETS
	Cash	$	52,124		$	45,998
	Investment in trust equities	3,716			3,716
	Investment in subsidiaries	611,468			575,023
	Other assets	8,279			7,280
		$	675,587		$	632,017
	LIABILITIES AND STOCKHOLDERS’ EQUITY
	Miscellaneous liabilities	$	2,446		$	6,157
	Deferred tax liability	11,516			12,960
	Junior subordinated debentures at fair value	78,001			73,928
	Stockholders’ equity	583,624			538,972
		$	675,587		$	632,017
Schedule of Condensed Statement of Operations
	Statements of Operations	Years Ended December 31
		2014			2013			2012
	INTEREST INCOME:
	Interest-bearing deposits	$	96		$	82		$	218
	OTHER INCOME (EXPENSE):
	Dividend income from subsidiaries	26,027			24,725			61,329
	Equity in undistributed income of subsidiaries	33,707			23,994			23,507
	Other income	67			3,016			55
	Net change in valuation of financial instruments carried at fair value	(4,073		)	(865		)	(23,075		)
	Interest on other borrowings	(2,914		)	(2,968		)	(3,395		)
	Other expenses	(2,519		)	(2,794		)	(2,375		)
	Net income before taxes	50,391			45,190			56,264
	BENEFIT FROM INCOME TAXES	(3,774		)	(1,365		)	(8,618		)
	NET INCOME	54,165			46,555			64,882
	PREFERRED STOCK DIVIDEND AND DISCOUNT ACCRETION
	Preferred stock dividend	—			—			4,938
	Preferred stock discount accretion	—			—			3,298
	Gain on repurchase of preferred stock	—			—			(2,471		)
	NET INCOME AVAILABLE TO COMMON SHAREHOLDERS	$	54,165		$	46,555		$	59,117
Schedule of Condensed Statement of Cash Flows
	Statements of Cash Flows	Years Ended December 31
		2014			2013			2012
	OPERATING ACTIVITIES:
	Net income	$	54,165		$	46,555		$	64,882
	Adjustments to reconcile net income to net cash provided by operating activities:
	Equity in undistributed earnings of subsidiaries	(33,707		)	(23,994		)	(23,507		)
	Increase (decrease) in deferred taxes	(1,444		)	17			(13,030		)
	Net change in valuation of financial instruments carried at fair value	4,073			865			23,075
	(Increase) decrease in other assets	(3,822		)	(4,655		)	(496		)
	Increase (decrease) in other liabilities	222			(1,921		)	4,940
	Net cash provided from operating activities	19,487			16,867			55,864
	INVESTING ACTIVITIES:
	Funds transferred to deferred compensation trust	(26		)	(27		)	(332		)
	Net cash used by investing activities	(26		)	(27		)	(332		)
	FINANCING ACTIVITIES:
	Issuance of stock for stockholder reinvestment program	127			72			36,317
	Redemption of senior preferred stock	—			—			(121,528		)
	Cash dividends paid	(13,462		)	(7,798		)	(6,470		)
	Net cash used by financing activities	(13,335		)	(7,726		)	(91,681		)
	NET INCREASE (DECREASE) IN CASH	6,126			9,114			(36,149		)
	CASH, BEGINNING OF PERIOD	45,998			36,884			73,033
	CASH, END OF PERIOD	$	52,124		$	45,998		$	36,884

CALCULATION_OF_EARNINGS_PER_CO1

CALCULATION OF EARNINGS PER COMMON SHARE (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Weighted Shares Outstanding	The following tables show the calculation of earnings (loss) per common share (in thousands, except per share data):
		Years Ended December 31
		2014		2013		2012
	Net income	$	54,165	$	46,555	$	64,882
	Preferred stock dividend accrual	—		—		(4,938		)
	Preferred stock discount accretion	—		—		(3,298		)
	Gain on repurchase of preferred stock	—		—		2,471
	Net income available to common shareholders	$	54,165	$	46,555	$	59,117
	Weighted average number of common shares outstanding
	Basic	19,359		19,361		18,650
	Diluted	19,403		19,397		18,723
	Earnings per common share
	Basic	$	2.8	$	2.4	$	3.17
	Diluted	$	2.79	$	2.4	$	3.16

SELECTED_QUARTERLY_FINANCIAL_D1

SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Tables)	12 Months Ended
	Dec. 31, 2014
Selected Quarterly Financial Information [Abstract]
Schedule of Quarterly Financial Information	Results of operations on a quarterly basis for the years ended December 31, 2014, 2013 and 2012 were as follows (dollars in thousands except for per share data):
		Year Ended December 31, 2014
		First		Second			Third			Fourth
		Quarter		Quarter			Quarter			Quarter
	Interest income	$	45,106	$	46,540		$	49,764		$	49,251
	Interest expense	2,767		2,732			2,700			2,590
	Net interest income before provision for loan losses	42,339		43,808			47,064			46,661
	Provision for loan losses	—		—			—			—
	Net interest income	42,339		43,808			47,064			46,661
	Other operating income	8,858		20,133			13,350			11,913
	Other operating expenses	35,581		38,435			38,495			41,230
	Income before provision for income taxes	15,616		25,506			21,919			17,344
	Provision for income taxes	5,046		8,499			7,076			5,599
	Net income	10,570		17,007			14,843			11,745
	Preferred stock dividend	—		—			—			—
	Preferred stock discount accretion	—		—			—			—
	Gain on repurchase and retirement of preferred stock	—		—			—			—
	Net income available to common shareholders	$	10,570	$	17,007		$	14,843		$	11,745
	Basic earnings per share	$	0.55	$	0.88		$	0.77		$	0.61
	Diluted earnings per share	0.54		0.88			0.76			0.6
	Dividends declared	0.18		0.18			0.18			0.18
		Year Ended December 31, 2013
		First		Second			Third			Fourth
		Quarter		Quarter			Quarter			Quarter
	Interest income	$	44,508	$	45,571		$	45,037		$	44,595
	Interest expense	3,540		3,323			3,144			2,988
	Net interest income before provision for loan losses	40,968		42,248			41,893			41,607
	Provision for loan losses	—		—			—			—
	Net interest income	40,968		42,248			41,893			41,607
	Other operating income	9,997		10,623			10,142			12,580
	Other operating expenses	34,099		35,457			34,490			36,929
	Income before provision for income taxes	16,866		17,414			17,545			17,258
	Provision for income taxes	5,284		5,661			5,880			5,704
	Net income	11,582		11,753			11,665			11,554
	Preferred stock dividend	—		—			—			—
	Preferred stock discount accretion	—		—			—			—
	Gain on repurchase and retirement of preferred stock	—		—			—			—
	Net income available to common shareholders	$	11,582	$	11,753		$	11,665		$	11,554
	Basic earnings per share	$	0.6	$	0.6		$	0.6		$	0.6
	Diluted earnings per share	0.6		0.6			0.6			0.6
	Dividends declared	0.12		0.12			0.15			0.15
		Year Ended December 31, 2012
		First		Second			Third			Fourth
		Quarter		Quarter			Quarter			Quarter
	Interest income	$	47,198	$	47,265		$	47,174		$	45,525
	Interest expense	6,072		4,975			4,476			3,991
	Net interest income before provision for loan losses	41,126		42,290			42,698			41,534
	Provision for loan losses	5,000		4,000			3,000			1,000
	Net interest income	36,126		38,290			39,698			40,534
	Other operating income	10,971		(9,064		)	11,684			13,311
	Other operating expenses	37,913		35,666			33,355			34,519
	Income (loss) before provision for income taxes	9,184		(6,440		)	18,027			19,326
	Provision (benefit) for income taxes	—		(31,830		)	2,407			4,638
	Net income	9,184		25,390			15,620			14,688
	Preferred stock dividend	1,550		1,550			1,227			611
	Preferred stock discount accretion	454		454			1,216			1,174
	Gain on repurchase and retirement of preferred stock	—		—			(2,070		)	(401		)
	Net income available to common shareholders	$	7,180	$	23,386		$	15,247		$	13,304
	Basic earnings per share	$	0.4	$	1.27		$	0.81		$	0.69
	Diluted earnings per share	0.4		1.27			0.8			0.69
	Dividends declared	0.01		0.01			0.01			0.01

FINANCIAL_INSTRUMENTS_WITH_OFF1

FINANCIAL INSTRUMENTS WITH OFF-BALANCE-SHEET RISK (Tables)	12 Months Ended
	Dec. 31, 2014
Financial Instruments with Off-Balance-Sheet Risk [Abstract]
Schedule of Financial Instruments With Off-Balance-Sheet Risks	Outstanding commitments for which no asset or liability for the notional amount has been recorded consisted of the following at the dates indicated (in thousands):
		Contract or Notional Amount
		December 31, 2014		December 31, 2013
	Commitments to extend credit	$	1,166,165	$	1,073,897
	Standby letters of credit and financial guarantees	9,934		6,990
	Commitments to originate loans	20,988		15,776
	Derivatives also included in Note 28:
	Commitments to originate loans held for sale	29,851		21,434
	Commitments to sell loans secured by one- to four-family residential properties	8,714		9,378
	Commitments to sell securities related to mortgage banking activities	25,000		15,200

DERIVATIVES_AND_HEDGING_DERIVA1

DERIVATIVES AND HEDGING DERIVATIVES AND HEDGING (Tables)	12 Months Ended
	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	As of December 31, 2014 and December 31, 2013, the notional values or contractual amounts and fair values of the Company's derivatives designated in hedge relationships were as follows (in thousands):
		Asset Derivatives													Liability Derivatives
		December 31, 2014								December 31, 2013					December 31, 2014					December 31, 2013
		Notional/				Fair				Notional/		Fair			Notional/			Fair		Notional/		Fair
		Contract Amount				Value (1)				Contract Amount		Value (1)			Contract Amount			Value (2)		Contract Amount		Value (2)
	Interest rate swaps	$	7,089			$	1,165			$	7,420	$	1,295		$	7,089		$	1,165	$	7,420	$	1,295
	(1)	Included in Loans Receivable on the Consolidated Statement of Financial Condition.
	(2)	Included in Other Liabilities on the Consolidated Statement of Financial Condition.
Schedule of Other Derivatives Not Designated as Hedging Instruments, Statements of Financial Performance and Financial Position, Location	As of December 31, 2014 and December 31, 2013, the notional values or contractual amounts and fair values of the Company's derivatives not designated in hedge relationships were as follows (in thousands):
		Asset Derivatives													Liability Derivatives
		December 31, 2014								December 31, 2013					December 31, 2014					December 31, 2013
		Notional/				Fair				Notional/		Fair			Notional/			Fair		Notional/		Fair
		Contract Amount				Value (1)				Contract Amount		Value (1)			Contract Amount			Value (2)		Contract Amount		Value (2)
	Interest rate swaps	$	134,512			$	5,125			$	135,122	$	3,651		$	134,512		$	5,125	$	135,122	$	3,651
	Mortgage loan commitments	29,311				317				14,107		57			—			—		7,326		43
	Forward sales contracts	—				—				22,526		73			33,174			198		—		—
		$	163,823			$	5,442			$	171,755	$	3,781		$	167,686		$	5,323	$	142,448	$	3,694
	(1)	Included in Other Assets on the Consolidated Statements of Financial Condition, with the exception of those interest rate swaps from prior to 2009 that were not designated in hedge relationships (with a fair value of $558,000 at December 31, 2014 and $791,000 at December 31, 2013), which are included in Loans Receivable.
	(2)	Included in Other Liabilities on the Consolidated Statements of Financial Condition.
	Gains (losses) recognized in income on non-designated hedging instruments for the years ended December 31, 2014 and 2013 were as follows (in thousands):
				For the Year Ended December 31
		Location on Income Statement		2014				2013
	Mortgage loan commitments	Mortgage banking operations		$	221			$	(174	)
	Forward sales contracts	Mortgage banking operations		(188		)		310
				$	33			$	136
Offsetting Assets and Liabilities	The following table illustrates the potential effect of the Company's derivative master netting arrangements, by type of financial instrument, on the Company's Consolidated Statements of Financial Condition as of December 31, 2014 and December 31, 2013 (in thousands):
		December 31, 2014
												Gross Amounts of Financial Instruments Not Offset in the Statement of Financial Condition
		Gross Amounts Recognized				Amounts offset in the Statement				Net Amounts		Netting Adjustment Per Applicable Master Netting Agreements			Fair Value			Net Amount
						of Financial Condition				in the Statement					of Financial Collateral
										of Financial Condition					in the Statement
															of Financial Condition
	Derivative assets
	Interest rate swaps	$	6,290			$	—			$	6,290	$	(6	)	$	—		$	6,284
		$	6,290			$	—			$	6,290	$	(6	)	$	—		$	6,284
	Derivative liabilities
	Interest rate swaps	$	6,290			$	—			$	6,290	$	(6	)	$	(6,279	)	$	5
		$	6,290			$	—			$	6,290	$	(6	)	$	(6,279	)	$	5
		December 31, 2013
												Gross Amounts of Financial Instruments Not Offset in the Statement of Financial Condition
		Gross Amounts Recognized				Amounts offset in the Statement				Net Amounts		Netting Adjustment Per Applicable Master Netting Agreements			Fair Value			Net Amount
						of Financial Condition				in the Statement					of Financial Collateral
										of Financial Condition					in the Statement
															of Financial Condition
	Derivative assets
	Interest rate swaps	$	4,946			$	—			$	4,946	$	(554	)	$	—		$	4,392
		$	4,946			$	—			$	4,946	$	(554	)	$	—		$	4,392
	Derivative liabilities
	Interest rate swaps	$	4,946			$	—			$	4,946	$	(554	)	$	(2,657	)	$	1,735
		$	4,946			$	—			$	4,946	$	(554	)	$	(2,657	)	$	1,735

BASIS_OF_PRESENTATION_AND_SUMM3

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Investment in FHLB Stock) (Details) (USD $)	12 Months Ended			24 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Federal Home Loan Bank stock	$27,036	$35,390		$27,036
Federal Home Loan Bank Stock, Par Value Per Share	$100			$100
Proceeds from FHLB stock repurchase program	8,354	1,315	666	9,700
FHLB stock—dividend income	34	18	0
Investment in Federal Home Loan Bank Stock [Member]
Schedule of Equity Method Investments [Line Items]
Federal Home Loan Bank Stock, Impairment	$0

BASIS_OF_PRESENTATION_AND_SUMM4

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Property, Plant and Equipment Useful Lives) (Details)	12 Months Ended
	Dec. 31, 2014
Buildings and leased improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	10 years
Buildings and leased improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	30 years
Furniture and equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	3 years
Furniture and equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	10 years

BASIS_OF_PRESENTATION_AND_SUMM5

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Textuals) (Details) (USD $)	12 Months Ended			9 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014	Dec. 31, 2007
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Number of wholly-owned subsidiaries	2			2
Cash surrender value of bank-owned life insurance policies	63,800,000	61,900,000		63,800,000
Subsidiary, Banner Bank [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Number of offices	90			90
Number of production offices	10			10
Subsidiary, Islanders Bank [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Number of locations	3			3
Minimum [Member] | Core Deposit Intangibles [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Intangible asset, useful life	3 years
Maximum [Member] | Core Deposit Intangibles [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Intangible asset, useful life	8 years
Loans Receivable [Member] | Interest Rate Swap [Member] | F&M Bank [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Derivative Asset, Notional Amount	13,000,000			13,000,000	23,000,000
Other assets [Member] | Interest Rate Swap [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Derivative Asset, Notional Amount	129,000,000			129,000,000
Restricted Stock [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Granted	90,181	98,891	92,035
Restricted Stock [Member] | 2014 Omnibus Incentive Plan [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Number of shares authorized	900,000			900,000
Granted				9,352

RECENT_DEVELOPMENTS_AND_SIGNIF1

RECENT DEVELOPMENTS AND SIGNIFICANT EVENTS RECENT DEVELOPMENTS AND SIGNIFICANT EVENTS (Proposed Acquisition of AmericanWest Bank) (Details) (Scenario, Plan [Member], USD $)	12 Months Ended
Share data in Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014
AmericanWest Bank [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Business Combination, Aggregate Consideration, Cash	$130,000,000
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable, Shares	13.23
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable, Acquiree Equity Interest in Acquirer	38.80%
AmericanWest Bank, excluding Greater Sacramento Bancorp
Business Combination, Separately Recognized Transactions [Line Items]
Business Combination, Acquired Assets		4,100,000,000
Business Combination, Acquired Receivables		2,500,000,000
Business Combination, Acquired Deposits		3,300,000,000
Business Combination, Equity of Acquired Entity		561,300,000
Greater Sacramento Bancorp [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Business Combination, Acquired Assets		481,000,000
Business Combination, Acquired Deposits		410,000,000
Business Combination, Equity of Acquired Entity		$39,000,000

RECENT_DEVELOPMENTS_AND_SIGNIF2

RECENT DEVELOPMENTS AND SIGNIFICANT EVENTS (Stockholder Equity Transactions) (Details) (USD $)	3 Months Ended												12 Months Ended			0 Months Ended	32 Months Ended	0 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Apr. 24, 2012	Dec. 31, 2014	Nov. 21, 2008	Dec. 31, 2011	Mar. 29, 2012	Mar. 26, 2014
Participation in the U.S. Treasury's Capital Purchase Program:
Preferred stock issued, value	$0				$0								$0	$0			0
Gain on repurchase of preferred stock	0	0	0	0	0	0	0	0	401,000	2,070,000	0	0	0	0	2,471,000
Restricted Stock [Member]
Restricted Stock Grants:
Granted													90,181	98,891	92,035
Vested													-56,307	-42,250	-11,419
Unvested, Ending Balance	195,106				164,492				107,851				195,106	164,492	107,851		195,106		28,735
2012 Restricted Stock and Incentive Bonus Plan [Member] | Restricted Stock [Member]
Restricted Stock Grants:
Number of shares authorized	300,000												300,000				300,000
Award vesting period																3 years
Plan maximum contractual term																10 years
Granted																	266,778
Vested																	-81,241
Unvested, Ending Balance	185,537												185,537				185,537
2012 Restricted Stock and Incentive Bonus Plan [Member] | Restricted Stock [Member] | Chief Executive Officer [Member]
Restricted Stock Grants:
Vesting increments																3
Series A Preferred Stock [Member] | Participation in the U.S. Treasury Capital Purchase Program [Member]
Stockholders Equity Transactions
Preferred stock aggregate liquidation preference																		124,000,000
Participation in the U.S. Treasury's Capital Purchase Program:
Preferred stock issued, value																				124,000,000
Preferred stock, liquidation value per share																		$1,000
Common Stock [Member] | Participation in the U.S. Treasury Capital Purchase Program [Member] | Warrant [Member]
Participation in the U.S. Treasury's Capital Purchase Program:
U.S. Treasury warrants, aggregate exercise price																		$18,600,000
Warrant, option to purchase common stock (in shares)																		243,998
U.S. Treasury warrants, term (in years)																		10 years
Banner Corporation Share Repurchase Plan [Member] | Common Stock [Member]
Restricted Stock Grants:
Stock Repurchase Program, Number of Shares Authorized to be Repurchased																					978,826

BUSINESS_COMBINATIONS_BUSINESS2

BUSINESS COMBINATIONS BUSINESS COMBINATIONS (Textual) (Details) (USD $)	12 Months Ended	3 Months Ended
	Dec. 31, 2014	Mar. 16, 2015	Jun. 20, 2014	Mar. 06, 2015
	location
Six Oregon Branches [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition	20-Jun-14
Business Combination, Number of Branches	6
Business Combination, Acquired Receivables			$87,923,000
Business Combination, Acquired Assets			221,206,000
Business Combination, Acquired Deposits			212,085,000
Acquisition bargain purchase gain			9,079,000
Discount on net asset acquired			7,000,000
Net fair value adjustments on acquired assets and assumed liabilities			300,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	8 years
Business Acquisition [Member] | Siuslaw Financial Group, Inc [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition		6-Mar-15
Business Combination, Aggregate Consideration, Total		63,900,000
Business Combination, Aggregate Consideration, Cash		5,800,000
Business Combination, Aggregate Consideration, Common Stock Issued		58,100,000
Business Combination, Acquired Receivables				252,000,000
Business Combination, Acquired Assets				370,000,000
Business Combination, Acquired Deposits				$318,000,000

BUSINESS_COMBINATIONS_BUSINESS3

BUSINESS COMBINATIONS BUSINESS COMBINATIONS (Schedule of Components of Acquisition) (Details) (Six Oregon Branches [Member], USD $)	Jun. 20, 2014
Six Oregon Branches [Member]
ASSETS
Cash	$127,557,000
Loans receivable (contractual amount of $88.3 million)	87,923,000
Property and equipment	3,079,000
Core deposit intangible	2,372,000
Other assets	275,000
Total assets	221,206,000
LIABILITIES
Deposits	212,085,000
Other liabilities	42,000
Total liabilities	212,127,000
Net assets acquired (Acquisition bargain purchase gain)	9,079,000
Business Combination, Acquired Receivables, Gross Contractual Amount	$88,300,000

BUSINESS_COMBINATIONS_BUSINESS4

BUSINESS COMBINATIONS BUSINESS COMBINATIONS (Schedule of Acquisition Related Costs) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Business Combinations [Abstract]
Non-capitalized equipment and repairs	$105	$0	$0
Client communications	327	0	0
Information/computer data services	334	0	0
Payment and processing expenses	185	0	0
Professional services	2,953	550	0
Miscellaneous	421	0	0
Total acquisition related costs	$4,325	$550	$0

CASH_AND_SECURITIES_Cash_and_C

CASH AND SECURITIES (Cash and Cash Equivalents) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Cash and Cash Equivalents, at Carrying Value [Abstract]
Cash on hand and due from banks	$125,689	$136,810
Cash equivalents:
Short-term cash investments	383	539
Cash and due from banks	$126,072	$137,349	$181,298	$132,436

CASH_AND_SECURITIES_Schedule_o

CASH AND SECURITIES (Schedule of Investments) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Investments [Line Items]
Interest-bearing deposits included in cash and due from banks	$54,995	$67,638
Marketable securities	582,537	635,265
Federal Home Loan Bank stock	27,036	35,390
Interest-bearing deposits and marketable securities	664,568	738,293
U.S. Government and agency obligations [Member]
Schedule of Investments [Line Items]
Marketable securities	33,421	61,327
Total municipal bonds [Member]
Schedule of Investments [Line Items]
Marketable securities	171,419	153,804
Taxable municipal bonds [Member]
Schedule of Investments [Line Items]
Marketable securities	29,566	34,216
Tax exempt municipal bonds [Member]
Schedule of Investments [Line Items]
Marketable securities	141,853	119,588
Corporate bonds [Member]
Schedule of Investments [Line Items]
Marketable securities	25,936	44,154
Total Mortgage-backed or related securities [Member]
Schedule of Investments [Line Items]
Marketable securities	326,307	350,721
1-4 residential agency guaranteed [Member]
Schedule of Investments [Line Items]
Marketable securities	58,825	58,117
1-4 residential other [Member]
Schedule of Investments [Line Items]
Marketable securities	713	1,051
Multifamily agency guaranteed [Member]
Schedule of Investments [Line Items]
Marketable securities	256,272	281,319
Multifamily other [Member]
Schedule of Investments [Line Items]
Marketable securities	10,497	10,234
Asset-backed securities [Member]
Schedule of Investments [Line Items]
Marketable securities	25,395	25,191
Student Loan Marketing Association SLMA [Member]
Schedule of Investments [Line Items]
Marketable securities	15,629	15,681
Other Asset-Backed Securities [Member]
Schedule of Investments [Line Items]
Marketable securities	9,766	9,510
Equity securities (excludes FHLB stock) [Member]
Schedule of Investments [Line Items]
Marketable securities	$59	$68

CASH_AND_SECURITIES_Trading_Se

CASH AND SECURITIES (Trading Securities) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amortized Cost	$47,480	$75,150
Securities—trading, Fair Value	40,258	62,472
Percent of Total	100.00%	100.00%
U.S. Government and agency obligations [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amortized Cost	1,340	1,370
Securities—trading, Fair Value	1,505	1,481
Percent of Total	3.70%	2.40%
Tax exempt municipal bonds [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amortized Cost	1,405	4,969
Securities—trading, Fair Value	1,440	5,023
Percent of Total	3.60%	8.00%
Corporate bonds [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amortized Cost	27,995	49,498
Securities—trading, Fair Value	19,118	35,140
Percent of Total	47.50%	56.20%
Total Mortgage-backed or related securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amortized Cost	16,726	19,299
Securities—trading, Fair Value	18,136	20,760
Percent of Total	45.10%	33.30%
1-4 residential agency guaranteed [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amortized Cost	8,077	10,483
Securities—trading, Fair Value	8,726	11,230
Percent of Total	21.70%	18.00%
Multifamily agency guaranteed [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amortized Cost	8,649	8,816
Securities—trading, Fair Value	9,410	9,530
Percent of Total	23.40%	15.30%
Equity securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Amortized Cost	14	14
Securities—trading, Fair Value	$59	$68
Percent of Total	0.10%	0.10%

CASH_AND_SECURITIES_Trading_Se1

CASH AND SECURITIES (Trading Securities Debt Maturities) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Amortized Cost
Maturing in one year or less	$1,071	$260
Maturing after one year through five years	6,595	7,056
Maturing after five years through ten years	7,035	12,602
Maturing after ten years through twenty years	11,196	33,335
Maturing after twenty years	21,569	21,883
Total with maturity date	47,466	75,136
Equity securities	14	14
Amortized Cost	47,480	75,150
Fair Value
Maturing in one year or less	1,094	263
Maturing after one year through five years	7,097	7,298
Maturing after five years through ten years	7,727	13,572
Maturing after ten years through twenty years	10,083	27,472
Maturing after twenty years	14,198	13,799
Total with maturity date	40,199	62,404
Equity securities	59	68
Securities—trading, Fair Value	$40,258	$62,472

CASH_AND_SECURITIES_Availablef

CASH AND SECURITIES (Available-for-sale Securities) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$411,424	$474,960
Gross Unrealized Gains	1,812	1,630
Gross Unrealized Losses	-2,215	-6,310
Fair Value	411,021	470,280
Percent of Total	100.00%	100.00%
U.S. Government and agency obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	29,973	59,178
Gross Unrealized Gains	8	117
Gross Unrealized Losses	-211	-635
Fair Value	29,770	58,660
Percent of Total	7.20%	12.50%
Total municipal bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	49,959	53,071
Gross Unrealized Gains	190	270
Gross Unrealized Losses	-121	-486
Fair Value	50,028	52,855
Percent of Total	12.20%	11.20%
Taxable municipal bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	16,565	23,842
Gross Unrealized Gains	65	100
Gross Unrealized Losses	-52	-278
Fair Value	16,578	23,664
Percent of Total	4.00%	5.00%
Tax exempt municipal bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	33,394	29,229
Gross Unrealized Gains	125	170
Gross Unrealized Losses	-69	-208
Fair Value	33,450	29,191
Percent of Total	8.20%	6.20%
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,000	7,001
Gross Unrealized Gains	18	2
Gross Unrealized Losses	0	-39
Fair Value	5,018	6,964
Percent of Total	1.20%	1.50%
Total Mortgage-backed or related securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	300,979	330,097
Gross Unrealized Gains	1,429	1,113
Gross Unrealized Losses	-1,598	-4,600
Fair Value	300,810	326,610
Percent of Total	73.20%	69.50%
1-4 residential agency guaranteed [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	48,001	47,077
Gross Unrealized Gains	758	648
Gross Unrealized Losses	-240	-838
Fair Value	48,519	46,887
Percent of Total	11.80%	10.00%
1-4 residential other [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	675	988
Gross Unrealized Gains	38	63
Gross Unrealized Losses	0	0
Fair Value	713	1,051
Percent of Total	0.20%	0.20%
Multifamily agency guaranteed [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	241,800	271,428
Gross Unrealized Gains	627	402
Gross Unrealized Losses	-1,346	-3,392
Fair Value	241,081	268,438
Percent of Total	58.70%	57.10%
Multifamily other [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,503	10,604
Gross Unrealized Gains	6	0
Gross Unrealized Losses	-12	-370
Fair Value	10,497	10,234
Percent of Total	2.50%	2.20%
Asset-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	25,513	25,613
Gross Unrealized Gains	167	128
Gross Unrealized Losses	-285	-550
Fair Value	25,395	25,191
Percent of Total	6.20%	5.30%
SLMA [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	15,462	15,553
Gross Unrealized Gains	167	128
Gross Unrealized Losses	0	0
Fair Value	15,629	15,681
Percent of Total	3.80%	3.30%
Other Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,051	10,060
Gross Unrealized Gains	0	0
Gross Unrealized Losses	-285	-550
Fair Value	$9,766	$9,510
Percent of Total	2.40%	2.00%

CASH_AND_SECURITIES_Availablef1

CASH AND SECURITIES (Available-for-sale Securities with Continuous Loss Position) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	$123,351	$292,992
Less than 12 Months, Unrealized Losses	-355	-4,803
12 Months or More, Fair Value	134,007	44,064
12 Months or More, Unrealized Losses	-1,860	-1,507
Total Fair Value	257,358	337,056
Unrealized Losses	-2,215	-6,310
U.S. Government and agency obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	15,983	39,621
Less than 12 Months, Unrealized Losses	-58	-633
12 Months or More, Fair Value	9,847	998
12 Months or More, Unrealized Losses	-153	-2
Total Fair Value	25,830	40,619
Unrealized Losses	-211	-635
Total municipal bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	16,322	23,797
Less than 12 Months, Unrealized Losses	-61	-466
12 Months or More, Fair Value	7,129	900
12 Months or More, Unrealized Losses	-60	-20
Total Fair Value	23,451	24,697
Unrealized Losses	-121	-486
Taxable municipal bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	7,247	15,580
Less than 12 Months, Unrealized Losses	-23	-261
12 Months or More, Fair Value	3,461	413
12 Months or More, Unrealized Losses	-29	-17
Total Fair Value	10,708	15,993
Unrealized Losses	-52	-278
Tax exempt municipal bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	9,075	8,217
Less than 12 Months, Unrealized Losses	-38	-205
12 Months or More, Fair Value	3,668	487
12 Months or More, Unrealized Losses	-31	-3
Total Fair Value	12,743	8,704
Unrealized Losses	-69	-208
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value		4,961
Less than 12 Months, Unrealized Losses		-39
12 Months or More, Fair Value		0
12 Months or More, Unrealized Losses		0
Total Fair Value		4,961
Unrealized Losses		-39
Total Mortgage-backed or related securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	91,046	224,613
Less than 12 Months, Unrealized Losses	-236	-3,665
12 Months or More, Fair Value	107,266	32,656
12 Months or More, Unrealized Losses	-1,362	-935
Total Fair Value	198,312	257,269
Unrealized Losses	-1,598	-4,600
1-4 residential agency guaranteed [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	6,287	14,972
Less than 12 Months, Unrealized Losses	-57	-133
12 Months or More, Fair Value	11,744	22,560
12 Months or More, Unrealized Losses	-183	-705
Total Fair Value	18,031	37,532
Unrealized Losses	-240	-838
Multifamily agency guaranteed [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	76,309	199,407
Less than 12 Months, Unrealized Losses	-167	-3,162
12 Months or More, Fair Value	95,522	10,096
12 Months or More, Unrealized Losses	-1,179	-230
Total Fair Value	171,831	209,503
Unrealized Losses	-1,346	-3,392
Multifamily other [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	8,450	10,234
Less than 12 Months, Unrealized Losses	-12	-370
12 Months or More, Fair Value	0	0
12 Months or More, Unrealized Losses	0	0
Total Fair Value	8,450	10,234
Unrealized Losses	-12	-370
Other Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or More, Fair Value	9,765	9,510
12 Months or More, Unrealized Losses	-285	-550
Total Fair Value	9,765	9,510
Unrealized Losses	($285)	($550)

CASH_AND_SECURITIES_Availablef2

CASH AND SECURITIES (Available-for-sale Securities Debt Maturities) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Amortized Cost
Maturing in one year or less	$9,334	$25,136
Maturing after one year through five years	278,629	322,493
Maturing after five years through ten years	45,425	58,468
Maturing after ten years through twenty years	13,846	15,535
Maturing after twenty years	64,190	53,328
Amoritzed cost	411,424	474,960
Fair Value
Maturing in one year or less	9,364	25,256
Maturing after one year through five years	277,439	319,489
Maturing after five years through ten years	45,610	57,782
Maturing after ten years through twenty years	13,879	15,135
Maturing after twenty years	64,729	52,618
Fair Value	$411,021	$470,280

CASH_AND_SECURITIES_Heldtomatu

CASH AND SECURITIES (Held-to-maturity Securities) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$131,258	$102,513
Gross Unrealized Gains	6,424	2,738
Gross Unrealized Losses	-74	-1,641
Fair Value	137,608	103,610
Held-to-maturity Securities, Amortized Cost Percent of Total Amortized Cost	100.00%	100.00%
U.S. Government and agency obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	2,146	1,186
Gross Unrealized Gains	0	0
Gross Unrealized Losses	-19	-80
Fair Value	2,127	1,106
Held-to-maturity Securities, Amortized Cost Percent of Total Amortized Cost	1.60%	1.10%
Total municipal bonds [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	119,951	95,926
Gross Unrealized Gains	6,319	2,738
Gross Unrealized Losses	-48	-1,503
Fair Value	126,222	97,161
Held-to-maturity Securities, Amortized Cost Percent of Total Amortized Cost	91.40%	93.60%
Taxable municipal bonds [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	12,988	10,552
Gross Unrealized Gains	371	193
Gross Unrealized Losses	-1	-204
Fair Value	13,358	10,541
Held-to-maturity Securities, Amortized Cost Percent of Total Amortized Cost	9.90%	10.30%
Tax exempt municipal bonds [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	106,963	85,374
Gross Unrealized Gains	5,948	2,545
Gross Unrealized Losses	-47	-1,299
Fair Value	112,864	86,620
Held-to-maturity Securities, Amortized Cost Percent of Total Amortized Cost	81.50%	83.30%
Corporate bonds [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	1,800	2,050
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	1,800	2,050
Held-to-maturity Securities, Amortized Cost Percent of Total Amortized Cost	1.40%	2.00%
1-4 residential agency guaranteed [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	1,580
Gross Unrealized Gains	1
Gross Unrealized Losses	-7
Fair Value	1,574
Held-to-maturity Securities, Amortized Cost Percent of Total Amortized Cost	1.20%
Mortgage-backed or related securities, multifamily agency guaranteed [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	5,781	3,351
Gross Unrealized Gains	104	0
Gross Unrealized Losses	0	-58
Fair Value	5,885	3,293
Held-to-maturity Securities, Amortized Cost Percent of Total Amortized Cost	4.40%	3.30%
Total Mortgage-backed or related securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	7,361
Gross Unrealized Gains	105
Gross Unrealized Losses	-7
Fair Value	$7,459
Held-to-maturity Securities, Amortized Cost Percent of Total Amortized Cost	5.60%

CASH_AND_SECURITIES_Heldtomatu1

CASH AND SECURITIES (Held-to-maturity Securities with Continuous Loss Position) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Held-to-maturity Securities [Line Items]
Less Than 12 Months, Fair Value	$10,839	$38,977
Less Than 12 Months, Unrealized Losses	-51	-1,530
12 Months or More, Fair Value	1,719	3,267
12 Months or More, Unrealized Losses	-23	-111
Total Fair Value	12,558	42,244
Total Unrealized Losses	-74	-1,641
U.S. Government and agency obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less Than 12 Months, Fair Value	0	1,106
Less Than 12 Months, Unrealized Losses	0	-80
12 Months or More, Fair Value	1,127	0
12 Months or More, Unrealized Losses	-19	0
Total Fair Value	1,127	1,106
Total Unrealized Losses	-19	-80
Total municipal bonds [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less Than 12 Months, Fair Value	9,821	34,578
Less Than 12 Months, Unrealized Losses	-44	-1,392
12 Months or More, Fair Value	592	3,267
12 Months or More, Unrealized Losses	-4	-111
Total Fair Value	10,413	37,845
Total Unrealized Losses	-48	-1,503
Taxable municipal bonds [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less Than 12 Months, Fair Value	724	3,344
Less Than 12 Months, Unrealized Losses	-1	-110
12 Months or More, Fair Value	0	2,964
12 Months or More, Unrealized Losses	0	-94
Total Fair Value	724	6,308
Total Unrealized Losses	-1	-204
Tax exempt municipal bonds [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less Than 12 Months, Fair Value	9,097	31,234
Less Than 12 Months, Unrealized Losses	-43	-1,282
12 Months or More, Fair Value	592	303
12 Months or More, Unrealized Losses	-4	-17
Total Fair Value	9,689	31,537
Total Unrealized Losses	-47	-1,299
Mortgage-backed or related securities, multifamily agency guaranteed [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less Than 12 Months, Fair Value		3,293
Less Than 12 Months, Unrealized Losses		-58
12 Months or More, Fair Value		0
12 Months or More, Unrealized Losses		0
Total Fair Value		3,293
Total Unrealized Losses		-58
1-4 residential agency guaranteed [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less Than 12 Months, Fair Value	1,018
Less Than 12 Months, Unrealized Losses	-7
12 Months or More, Fair Value	0
12 Months or More, Unrealized Losses	0
Total Fair Value	1,018
Total Unrealized Losses	($7)

CASH_AND_SECURITIES_Heldtomatu2

CASH AND SECURITIES (Held-to-maturity Securities Debt Maturities) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Amortized Cost
Maturing in one year or less	$767	$1,270
Maturing after one year through five years	14,962	10,834
Maturing after five years through ten years	24,233	17,948
Maturing after ten years through twenty years	76,029	59,643
Maturing after twenty years	15,267	12,818
Amortized cost	131,258	102,513
Fair Value
Maturing in one year or less	771	1,281
Maturing after one year through five years	15,184	11,206
Maturing after five years through ten years	24,678	17,908
Maturing after ten years through twenty years	81,361	60,791
Maturing after twenty years	15,614	12,424
Fair Value	$137,608	$103,610

CASH_AND_SECURITIES_Securities

CASH AND SECURITIES (Securities Pledged) (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Pledged Financial Instruments, Not Separately Reported, Securities [Abstract]
State and local governments public deposits, carrying value	$116,273
Interest rate swap counterparties, carrying value	11,051
Retail repurchase transaction accounts, carrying value	98,735
Other, carrying value	248
Total pledged securities, carrying value	226,307
State and local governments public deposits, amortized cost	116,242
Interest rate swap counterparties, amortized cost	10,648
Retail repurchase transaction accounts, amortized cost	98,435
Other, amortized cost	248
Total pledged securities, amortized cost	225,573
State and local governments public deposits, fair value	122,130
Interest rate swap counterparties, fair value	11,051
Retail repurchase transaction accounts, fair value	98,735
Other, fair value	248
Total pledged securities, fair value	$232,164

CASH_AND_SECURITIES_CASH_AND_S

CASH AND SECURITIES CASH AND SECURITIES (Interest Income from Securities and Cash Equivalents) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Interest and Other Income [Abstract]
Mortgage-backed securities interest	$5,779	$5,168	$4,176
Other taxable interest income	3,101	3,601	5,087
Tax-exempt interest income	4,206	3,721	3,577
FHLB stock—dividend income	34	18	0
Total interest income from securities and cash equivalents	$13,120	$12,508	$12,840

CASH_AND_SECURITIES_Textuals_D

CASH AND SECURITIES (Textuals) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	security	security	security
Cash and Cash Equivalents [Abstract]
Required cash reserve	$33,000,000	$30,000,000
Trading Securities [Abstract]
Trading securities, number of securities sold	3	44	8
Trading securites, proceeds from sale	2,387,000	34,308,000	5,073,000
Trading Securities, Realized Gain (Loss)	1,000	1,500,000	13,000
Trading Securities, Realized Gain, Recoveries		1,000,000
Trading securities, OTTI charges	0	-409,000	409,000
Trading securities, number of securities in nonaccrual status	0	0	0
Trading securities, unrealized holding gain	5,500,000
Available-for-sale Securities [Abstract]
Available-for-sale securities, number of securities sold	13	35	3
Available-for-sale securities, sale proceeds	56,300,000	103,300,000	13,300,000
Available-for-sale securities, OTTI charges	0	0	0
Available-for-sale securities, gross realized gain (loss)	41,000	-116,000	38,000
Available-for-sale securities, unrealized loss position, number of securities	94	114	52
Available-for-sale Securities, Number of Securities in Nonaccrual Status	0		0
Held-to-maturity Securities [Abstract]
Held-to-maturity securities, number of securities sold	0	0	0
Held-to-maturity securities, OTTI charge (recovery)	$0	$0	$0
Held-to-maturity securities, number of securities in nonaccrual status	0	0	0
Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	25	36	5

LOANS_RECEIVABLE_AND_THE_ALLOW2

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Loans by Type) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	$3,833,820,000	$3,418,445,000
Less allowance for loan losses	-75,907,000	-74,258,000	-76,759,000
Total loans, net	3,757,913,000	3,344,187,000
Percent of total loans	100.00%	100.00%
Unearned, unamortized loan fees (and costs)	-5,800,000	-8,300,000
Commerical real estate - owner-occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	546,783,000	502,601,000
Percent of total loans	14.30%	14.70%
Commerical real estate - investment properties [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	856,942,000	692,457,000
Percent of total loans	22.30%	20.20%
Multifamily real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	167,524,000	137,153,000
Less allowance for loan losses	-4,562,000	-5,306,000	-4,506,000
Percent of total loans	4.40%	4.00%
Commercial construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	17,337,000	12,168,000
Percent of total loans	0.40%	0.40%
Multifamily construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	60,193,000	52,081,000
Percent of total loans	1.60%	1.50%
One-to four-family construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	219,889,000	200,864,000
Percent of total loans	5.70%	5.90%
Land and land development - residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	102,435,000	75,695,000
Percent of total loans	2.70%	2.20%
Land and land development - commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	11,152,000	10,450,000
Percent of total loans	0.30%	0.30%
Commercial business [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	723,964,000	682,169,000
Less allowance for loan losses	-12,043,000	-11,773,000	-9,957,000
Percent of total loans	18.90%	20.00%
Agricultural business, including secured by farmland [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	238,499,000	228,291,000
Less allowance for loan losses	-3,821,000	-2,841,000	-2,295,000
Percent of total loans	6.20%	6.70%
One- to four-family residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	539,894,000	529,494,000
Less allowance for loan losses	-5,447,000	-11,486,000	-16,475,000
Percent of total loans	14.10%	15.50%
Consumer secured by one- to four-family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	222,205,000	173,188,000
Percent of total loans	5.80%	5.10%
Consumer - other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	$127,003,000	$121,834,000
Percent of total loans	3.30%	3.50%

LOANS_RECEIVABLE_AND_THE_ALLOW3

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Loans by Geographic Type) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$3,833,820	$3,418,445
Percent of total loans	100.00%	100.00%
Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,358,106
Percent of total loans	61.50%
Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	869,649
Percent of total loans	22.70%
Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	319,154
Percent of total loans	8.30%
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	286,911
Percent of total loans	7.50%
Commerical real estate - owner-occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	546,783	502,601
Percent of total loans	14.30%	14.70%
Commerical real estate - owner-occupied [Member] | Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	383,950
Commerical real estate - owner-occupied [Member] | Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	86,937
Commerical real estate - owner-occupied [Member] | Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	56,348
Commerical real estate - owner-occupied [Member] | Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	19,548
Commerical real estate - investment properties [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	856,942	692,457
Percent of total loans	22.30%	20.20%
Commerical real estate - investment properties [Member] | Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	523,806
Commerical real estate - investment properties [Member] | Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	124,604
Commerical real estate - investment properties [Member] | Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	60,053
Commerical real estate - investment properties [Member] | Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	148,479
Multifamily real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	167,524	137,153
Percent of total loans	4.40%	4.00%
Multifamily real estate [Member] | Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	116,793
Multifamily real estate [Member] | Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	35,527
Multifamily real estate [Member] | Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	14,759
Multifamily real estate [Member] | Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	445
Commercial construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	17,337	12,168
Percent of total loans	0.40%	0.40%
Commercial construction [Member] | Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	15,599
Commercial construction [Member] | Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	0
Commercial construction [Member] | Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,738
Commercial construction [Member] | Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	0
Multifamily construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	60,193	52,081
Percent of total loans	1.60%	1.50%
Multifamily construction [Member] | Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	50,931
Multifamily construction [Member] | Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	8,850
Multifamily construction [Member] | Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	412
Multifamily construction [Member] | Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	0
One-to four-family construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	219,889	200,864
Percent of total loans	5.70%	5.90%
One-to four-family construction [Member] | Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	129,499
One-to four-family construction [Member] | Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	88,468
One-to four-family construction [Member] | Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,922
One-to four-family construction [Member] | Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	0
Land and land development - residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	102,435	75,695
Percent of total loans	2.70%	2.20%
Land and land development - residential [Member] | Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	56,675
Land and land development - residential [Member] | Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	44,707
Land and land development - residential [Member] | Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,053
Land and land development - residential [Member] | Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	0
Land and land development - commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	11,152	10,450
Percent of total loans	0.30%	0.30%
Land and land development - commercial [Member] | Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	5,781
Land and land development - commercial [Member] | Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,529
Land and land development - commercial [Member] | Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,842
Land and land development - commercial [Member] | Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	0
Commercial business [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	723,964	682,169
Percent of total loans	18.90%	20.00%
Commercial business [Member] | Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	397,103
Commercial business [Member] | Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	125,235
Commercial business [Member] | Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	85,580
Commercial business [Member] | Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	116,046
Agricultural business, including secured by farmland [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	238,499	228,291
Percent of total loans	6.20%	6.70%
Agricultural business, including secured by farmland [Member] | Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	119,617
Agricultural business, including secured by farmland [Member] | Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	69,843
Agricultural business, including secured by farmland [Member] | Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	48,997
Agricultural business, including secured by farmland [Member] | Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	42
One- to four-family residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	539,894	529,494
Percent of total loans	14.10%	15.50%
One- to four-family residential [Member] | Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	341,944
One- to four-family residential [Member] | Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	172,974
One- to four-family residential [Member] | Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	24,223
One- to four-family residential [Member] | Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	753
Consumer secured by one- to four-family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	222,205	173,188
Percent of total loans	5.80%	5.10%
Consumer secured by one- to four-family [Member] | Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	136,888
Consumer secured by one- to four-family [Member] | Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	69,172
Consumer secured by one- to four-family [Member] | Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	14,984
Consumer secured by one- to four-family [Member] | Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,161
Consumer - other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	127,003	121,834
Percent of total loans	3.30%	3.50%
Consumer - other [Member] | Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	79,520
Consumer - other [Member] | Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	40,803
Consumer - other [Member] | Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	6,243
Consumer - other [Member] | Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$437

LOANS_RECEIVABLE_AND_THE_ALLOW4

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Land and Land Development by State) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$3,833,820	$3,418,445
Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,358,106
Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	869,649
Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	319,154
Land and land development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	113,587
Percent of land and land development loans	100.00%
Land and land development [Member] | Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	62,456
Percent of land and land development loans	55.00%
Land and land development [Member] | Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	47,236
Percent of land and land development loans	41.60%
Land and land development [Member] | Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	3,895
Percent of land and land development loans	3.40%
Land and land development - residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	102,435	75,695
Land and land development - residential [Member] | Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	56,675
Land and land development - residential [Member] | Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	44,707
Land and land development - residential [Member] | Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,053
Land and land development - residential [Member] | Acquisition and development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	54,195
Land and land development - residential [Member] | Acquisition and development [Member] | Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	28,901
Land and land development - residential [Member] | Acquisition and development [Member] | Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	24,378
Land and land development - residential [Member] | Acquisition and development [Member] | Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	916
Land and land development - residential [Member] | Improved land and lots [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	39,102
Land and land development - residential [Member] | Improved land and lots [Member] | Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	21,703
Land and land development - residential [Member] | Improved land and lots [Member] | Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	17,262
Land and land development - residential [Member] | Improved land and lots [Member] | Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	137
Land and land development - residential [Member] | Unimproved land [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	9,138
Land and land development - residential [Member] | Unimproved land [Member] | Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	6,071
Land and land development - residential [Member] | Unimproved land [Member] | Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	3,067
Land and land development - residential [Member] | Unimproved land [Member] | Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	0
Land and land development - commercial and industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	11,152	10,450
Land and land development - commercial and industrial [Member] | Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	5,781
Land and land development - commercial and industrial [Member] | Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,529
Land and land development - commercial and industrial [Member] | Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,842
Land and land development - commercial and industrial [Member] | Improved land and lots [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	6,011
Land and land development - commercial and industrial [Member] | Improved land and lots [Member] | Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	3,750
Land and land development - commercial and industrial [Member] | Improved land and lots [Member] | Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	478
Land and land development - commercial and industrial [Member] | Improved land and lots [Member] | Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,783
Land and land development - commercial and industrial [Member] | Unimproved land [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	5,141
Land and land development - commercial and industrial [Member] | Unimproved land [Member] | Washington [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,031
Land and land development - commercial and industrial [Member] | Unimproved land [Member] | Oregon [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,051
Land and land development - commercial and industrial [Member] | Unimproved land [Member] | Idaho [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$1,059

LOANS_RECEIVABLE_AND_THE_ALLOW5

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Fixed-rate and Adjustable-Rate Maturity) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fixed-rate (term to maturity):
Maturing in one year or less	$115,571	$122,313
Maturing after one year through three years	184,707	143,322
Maturing after three years through five years	180,449	187,279
Maturing after five years through ten years	240,742	209,869
Maturing after ten years	572,793	439,004
Total fixed-rate loans	-1,294,262	-1,101,787
Adjustable-Rate (term to rate adjustment):
Maturing or repricing in one year or less	1,468,316	1,390,579
Maturing or repricing after one year through three years	416,433	279,791
Maturing or repricing after three years through five years	566,371	541,529
Maturing or repricing after five years through ten years	87,506	99,503
Maturing or repricing after ten years	932	5,256
Total adjustable-rate loans	-2,539,558	-2,316,658
Total loans outstanding	$3,833,820	$3,418,445

LOANS_RECEIVABLE_AND_THE_ALLOW6

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Loans to Related Parties) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Loans and Leases Receivable, Related Parties [Roll Forward]
Balance at beginning of year	$15,976	$12,463
New loans or advances	38,241	39,921
Repayments and adjustments	-45,608	-36,408
Balance at end of period	$8,609	$15,976

LOANS_RECEIVABLE_AND_THE_ALLOW7

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Impaired Loans and Related Allowance Reserve) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Financing Receivable, Impaired [Line Items]
Nonaccrual loans	$14,562	$21,908
Loans past due and still accruing	2,175	2,860
Troubled debt restructuring on accrual	29,154	47,428
Total impaired loans	45,891	72,196
Nonaccrual loans, allocated reserves	179	494
Loans past due and still accruing, allocated reserves	10	25
Troubled debt restructuring on accrual, allocated reserves	2,903	4,958
Total impaired loans, allocated reserves	3,092	5,477
Commitments to advance funds to TDRs	2,100	225
Commerical real estate - owner-occupied [Member]
Financing Receivable, Impaired [Line Items]
Nonaccrual loans	1,365	2,466
Loans past due and still accruing	0	0
Troubled debt restructuring on accrual	184	186
Total impaired loans	1,548	2,652
Nonaccrual loans, allocated reserves	20	31
Troubled debt restructuring on accrual, allocated reserves	4	4
Total impaired loans, allocated reserves	24	35
Commerical real estate - investment properties [Member]
Financing Receivable, Impaired [Line Items]
Nonaccrual loans	32	3,821
Loans past due and still accruing	0	0
Troubled debt restructuring on accrual	6,021	5,367
Total impaired loans	6,054	9,188
Nonaccrual loans, allocated reserves	5	89
Troubled debt restructuring on accrual, allocated reserves	724	415
Total impaired loans, allocated reserves	729	504
Multifamily real estate [Member]
Financing Receivable, Impaired [Line Items]
Loans past due and still accruing	0	0
Troubled debt restructuring on accrual	786	5,744
Total impaired loans	786	5,744
Troubled debt restructuring on accrual, allocated reserves	86	1,139
Total impaired loans, allocated reserves	86	1,139
One-to four-family construction [Member]
Financing Receivable, Impaired [Line Items]
Nonaccrual loans	0	269
Loans past due and still accruing	0	0
Troubled debt restructuring on accrual	3,923	6,864
Total impaired loans	3,923	7,133
Nonaccrual loans, allocated reserves	0	0
Troubled debt restructuring on accrual, allocated reserves	640	1,002
Total impaired loans, allocated reserves	640	1,002
Land and land development - residential [Member]
Financing Receivable, Impaired [Line Items]
Nonaccrual loans	1,275	924
Loans past due and still accruing	0	0
Troubled debt restructuring on accrual	1,279	4,061
Total impaired loans	2,554	4,985
Nonaccrual loans, allocated reserves	0	6
Troubled debt restructuring on accrual, allocated reserves	346	754
Total impaired loans, allocated reserves	346	760
Land and land development - commercial [Member]
Financing Receivable, Impaired [Line Items]
Loans past due and still accruing	0	0
Commercial business [Member]
Financing Receivable, Impaired [Line Items]
Nonaccrual loans	537	724
Loans past due and still accruing	0	0
Troubled debt restructuring on accrual	739	1,299
Total impaired loans	1,276	2,022
Nonaccrual loans, allocated reserves	46	104
Troubled debt restructuring on accrual, allocated reserves	82	222
Total impaired loans, allocated reserves	128	326
Agricultural business, including secured by farmland [Member]
Financing Receivable, Impaired [Line Items]
Nonaccrual loans	1,597	0
Loans past due and still accruing	0	105
Total impaired loans	1,597	105
Nonaccrual loans, allocated reserves	26	0
Loans past due and still accruing, allocated reserves	0	8
Total impaired loans, allocated reserves	26	8
One- to four-family residential [Member]
Financing Receivable, Impaired [Line Items]
Nonaccrual loans	8,507	12,532
Loans past due and still accruing	2,095	2,611
Troubled debt restructuring on accrual	15,792	23,302
Total impaired loans	26,394	38,445
Nonaccrual loans, allocated reserves	35	250
Loans past due and still accruing, allocated reserves	10	16
Troubled debt restructuring on accrual, allocated reserves	987	1,355
Total impaired loans, allocated reserves	1,032	1,621
Consumer secured by one- to four-family [Member]
Financing Receivable, Impaired [Line Items]
Nonaccrual loans	838	903
Loans past due and still accruing	80	13
Troubled debt restructuring on accrual	233	360
Total impaired loans	1,151	1,276
Nonaccrual loans, allocated reserves	47	13
Loans past due and still accruing, allocated reserves	0	0
Troubled debt restructuring on accrual, allocated reserves	28	33
Total impaired loans, allocated reserves	75	46
Consumer - other [Member]
Financing Receivable, Impaired [Line Items]
Nonaccrual loans	411	269
Loans past due and still accruing	0	131
Troubled debt restructuring on accrual	197	245
Total impaired loans	608	646
Nonaccrual loans, allocated reserves	0	1
Loans past due and still accruing, allocated reserves	0	1
Troubled debt restructuring on accrual, allocated reserves	6	34
Total impaired loans, allocated reserves	$6	$36

LOANS_RECEIVABLE_AND_THE_ALLOW8

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Impaired Loans With and Without Specific Reserves) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Financing Receivable, Impaired [Line Items]
Recorded Investment	$45,891		$72,196
Unpaid Principal Balance	49,319		78,371
Related Allowance	3,092		5,477
Average Recorded Investment	45,440		74,349
Interest Income Recognized	1,528		2,195
Commerical real estate - owner-occupied [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	1,548		2,652
Unpaid Principal Balance	1,598		2,702
Related Allowance	24		35
Average Recorded Investment	1,841		2,761
Interest Income Recognized	12		12
Commerical real estate - investment properties [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	6,054		9,188
Unpaid Principal Balance	6,458		11,369
Related Allowance	729		504
Average Recorded Investment	6,145		8,977
Interest Income Recognized	315		241
Multifamily real estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	786		5,744
Unpaid Principal Balance	786		5,744
Related Allowance	86		1,139
Average Recorded Investment	795		5,705
Interest Income Recognized	45		298
One-to four-family construction [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	3,923		7,133
Unpaid Principal Balance	3,923		7,213
Related Allowance	640		1,002
Average Recorded Investment	2,655		5,870
Interest Income Recognized	118		239
Land and land development - residential [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	2,554		4,985
Unpaid Principal Balance	3,710		6,140
Related Allowance	346		760
Average Recorded Investment	2,872		6,053
Interest Income Recognized	89		221
Commercial business [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	1,276		2,022
Unpaid Principal Balance	1,502		2,338
Related Allowance	128		326
Average Recorded Investment	1,328		2,236
Interest Income Recognized	41		59
Agricultural business, including secured by farmland [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	1,597		105
Unpaid Principal Balance	1,597		105
Related Allowance	26		8
Average Recorded Investment	1,866		110
Interest Income Recognized	0		8
One- to four-family residential [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	26,394		38,445
Unpaid Principal Balance	27,855		40,669
Related Allowance	1,032		1,621
Average Recorded Investment	26,093		40,557
Interest Income Recognized	870		1,063
Consumer secured by one- to four-family [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	1,151		1,276
Unpaid Principal Balance	1,256		1,420
Related Allowance	75		46
Average Recorded Investment	1,248		1,403
Interest Income Recognized	19		25
Consumer - other [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	608		646
Unpaid Principal Balance	634		671
Related Allowance	6		36
Average Recorded Investment	597		677
Interest Income Recognized	19		29
Without a specific allowance reserve [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	11,445	[1]	11,549	[1]
Unpaid Principal Balance	12,534	[1]	13,230	[1]
Related Allowance	126	[1]	289	[1]
Average Recorded Investment	10,650	[1]	12,275	[1]
Interest Income Recognized	32	[1]	48	[1]
Without a specific allowance reserve [Member] | Commerical real estate - owner-occupied [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	399	[1]	534	[1]
Unpaid Principal Balance	449	[1]	584	[1]
Related Allowance	20	[1]	31	[1]
Average Recorded Investment	526	[1]	569	[1]
Interest Income Recognized	0	[1]	0	[1]
Without a specific allowance reserve [Member] | Commerical real estate - investment properties [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	32	[1]	429	[1]
Unpaid Principal Balance	32	[1]	974	[1]
Related Allowance	5	[1]	89	[1]
Average Recorded Investment	44	[1]	624	[1]
Interest Income Recognized	0	[1]	0	[1]
Without a specific allowance reserve [Member] | Commercial business [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	537	[1]	724	[1]
Unpaid Principal Balance	763	[1]	1,040	[1]
Related Allowance	46	[1]	104	[1]
Average Recorded Investment	566	[1]	896	[1]
Interest Income Recognized	0	[1]	0	[1]
Without a specific allowance reserve [Member] | Agricultural business, including secured by farmland [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	853	[1]	105	[1]
Unpaid Principal Balance	853	[1]	105	[1]
Related Allowance	26	[1]	8	[1]
Average Recorded Investment	1,122	[1]	110	[1]
Interest Income Recognized	0	[1]	8	[1]
Without a specific allowance reserve [Member] | One- to four-family residential [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	8,546	[1]	8,611	[1]
Unpaid Principal Balance	9,244	[1]	9,229	[1]
Related Allowance	18	[1]	42	[1]
Average Recorded Investment	7,284	[1]	8,889	[1]
Interest Income Recognized	29	[1]	31	[1]
Without a specific allowance reserve [Member] | Consumer secured by one- to four-family [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	783	[1]	870	[1]
Unpaid Principal Balance	888	[1]	1,013	[1]
Related Allowance	11	[1]	13	[1]
Average Recorded Investment	838	[1]	900	[1]
Interest Income Recognized	3	[1]	1	[1]
Without a specific allowance reserve [Member] | Consumer - other [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	295	[1]	276	[1]
Unpaid Principal Balance	305	[1]	285	[1]
Related Allowance	0	[1]	2	[1]
Average Recorded Investment	270	[1]	287	[1]
Interest Income Recognized	0	[1]	8	[1]
With a specific allowance reserve [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	34,446	[2]	60,647	[2]
Unpaid Principal Balance	36,785	[2]	65,141	[2]
Related Allowance	2,966	[2]	5,188	[2]
Average Recorded Investment	34,790	[2]	62,074	[2]
Interest Income Recognized	1,496	[2]	2,147	[2]
With a specific allowance reserve [Member] | Commerical real estate - owner-occupied [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	1,149	[2]	2,118	[2]
Unpaid Principal Balance	1,149	[2]	2,118	[2]
Related Allowance	4	[2]	4	[2]
Average Recorded Investment	1,315	[2]	2,192	[2]
Interest Income Recognized	12	[2]	12	[2]
With a specific allowance reserve [Member] | Commerical real estate - investment properties [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	6,022	[2]	8,759	[2]
Unpaid Principal Balance	6,426	[2]	10,395	[2]
Related Allowance	724	[2]	415	[2]
Average Recorded Investment	6,101	[2]	8,353	[2]
Interest Income Recognized	315	[2]	241	[2]
With a specific allowance reserve [Member] | Multifamily real estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	786	[2]	5,744	[2]
Unpaid Principal Balance	786	[2]	5,744	[2]
Related Allowance	86	[2]	1,139	[2]
Average Recorded Investment	795	[2]	5,705	[2]
Interest Income Recognized	45	[2]	298	[2]
With a specific allowance reserve [Member] | One-to four-family construction [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	3,923	[2]	7,133	[2]
Unpaid Principal Balance	3,923	[2]	7,213	[2]
Related Allowance	640	[2]	1,002	[2]
Average Recorded Investment	2,655	[2]	5,870	[2]
Interest Income Recognized	118	[2]	239	[2]
With a specific allowance reserve [Member] | Land and land development - residential [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	2,554	[2]	4,985	[2]
Unpaid Principal Balance	3,710	[2]	6,140	[2]
Related Allowance	346	[2]	760	[2]
Average Recorded Investment	2,872	[2]	6,053	[2]
Interest Income Recognized	89	[2]	221	[2]
With a specific allowance reserve [Member] | Commercial business [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	739	[2]	1,298	[2]
Unpaid Principal Balance	739	[2]	1,298	[2]
Related Allowance	82	[2]	222	[2]
Average Recorded Investment	762	[2]	1,340	[2]
Interest Income Recognized	41	[2]	59	[2]
With a specific allowance reserve [Member] | Agricultural business, including secured by farmland [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	744	[2]
Unpaid Principal Balance	744	[2]
Related Allowance	0	[2]
Average Recorded Investment	744	[2]
Interest Income Recognized	0	[2]
With a specific allowance reserve [Member] | One- to four-family residential [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	17,848	[2]	29,834	[2]
Unpaid Principal Balance	18,611	[2]	31,440	[2]
Related Allowance	1,014	[2]	1,579	[2]
Average Recorded Investment	18,809	[2]	31,668	[2]
Interest Income Recognized	841	[2]	1,032	[2]
With a specific allowance reserve [Member] | Consumer secured by one- to four-family [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	368	[2]	406	[2]
Unpaid Principal Balance	368	[2]	407	[2]
Related Allowance	64	[2]	33	[2]
Average Recorded Investment	410	[2]	503	[2]
Interest Income Recognized	16	[2]	24	[2]
With a specific allowance reserve [Member] | Consumer - other [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	313	[2]	370	[2]
Unpaid Principal Balance	329	[2]	386	[2]
Related Allowance	6	[2]	34	[2]
Average Recorded Investment	327	[2]	390	[2]
Interest Income Recognized	$19	[2]	$21	[2]
[1]	Loans without a specific allowance reserve have not been individually evaluated for impairment, but have been included in pools of homogeneous loans for evaluation of related allowance reserves.
[2]	Loans with a specific allowance reserve have been individually evaluated for impairment using either a discounted cash flow analysis or, for collateral dependent loans, current appraisals to establish realizable value. These analyses may identify a specific impairment amount needed or may conclude that no reserve is needed. Any specific impairment that is identified is included in the category’s "Related Allowance" column.

LOANS_RECEIVABLE_AND_THE_ALLOW9

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Troubled Debt Restructuring) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Financing Receivable, Troubled Debt Restructurings [Line Items]
Accrual Status	$29,154	$47,428
Nonaccrual Status	2,349	5,699
Total TDRs	31,503	53,127
Commerical real estate - owner-occupied [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Accrual Status	183	186
Nonaccrual Status	109	613
Total TDRs	292	799
Commerical real estate - investment properties [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Accrual Status	6,021	5,367
Nonaccrual Status	32	1,630
Total TDRs	6,053	6,997
Multifamily real estate [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Accrual Status	786	5,744
Nonaccrual Status	0	0
Total TDRs	786	5,744
One-to four-family construction [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Accrual Status	3,923	6,864
Nonaccrual Status	0	269
Total TDRs	3,923	7,133
Land and land development - residential [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Accrual Status	1,279	4,061
Nonaccrual Status	525	174
Total TDRs	1,804	4,235
Commercial business [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Accrual Status	739	1,299
Nonaccrual Status	87	164
Total TDRs	826	1,463
One- to four-family residential [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Accrual Status	15,793	23,302
Nonaccrual Status	1,363	2,474
Total TDRs	17,156	25,776
Consumer secured by one- to four-family [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Accrual Status	233	360
Nonaccrual Status	117	252
Total TDRs	350	612
Consumer - other [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Accrual Status	197	245
Nonaccrual Status	116	123
Total TDRs	$313	$368

Recovered_Sheet1

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Newly Restructured Loans) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
	contract		contract
Financing Receivable, Troubled Debt Restructurings [Line Items]
Number of Contracts	17		23
Pre-Modification Outstanding Recorded Investment	$3,370		$8,558
Post-Modification Outstanding Recorded Investment	3,327		8,558
Commerical real estate - owner-occupied [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Number of Contracts	1		1
Pre-Modification Outstanding Recorded Investment	203		1,246
Post-Modification Outstanding Recorded Investment	203		1,246
Multifamily real estate [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Number of Contracts			1
Pre-Modification Outstanding Recorded Investment			375
Post-Modification Outstanding Recorded Investment			375
One-to four-family construction [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Number of Contracts	10		8
Pre-Modification Outstanding Recorded Investment	2,153		3,082
Post-Modification Outstanding Recorded Investment	2,153		3,082
Land and land development - residential [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Number of Contracts			2
Pre-Modification Outstanding Recorded Investment			1,029
Post-Modification Outstanding Recorded Investment			1,029
Commercial business [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Number of Contracts	1		1
Pre-Modification Outstanding Recorded Investment	100		100
Post-Modification Outstanding Recorded Investment	100		100
One- to four-family residential [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Number of Contracts	4		10
Pre-Modification Outstanding Recorded Investment	905		2,726
Post-Modification Outstanding Recorded Investment	862		2,726
Consumer - other [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Number of Contracts	1	[1],[2]
Pre-Modification Outstanding Recorded Investment	9	[1],[2]
Post-Modification Outstanding Recorded Investment	$9	[1],[2]
[1]	Since most loans were already considered classified and/or on non-accrual status prior to restructuring, the modifications did not have a material effect on the Company’s determination of the allowance for loan losses.
[2]	The majority of these modifications do not fit into one separate type, such as: rate, term, amount, interest-only or payment; but instead are a combination of multiple types of modifications, therefore they are disclosed in aggregate.

Recovered_Sheet2

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Troubled Debt Restructuring Which Incurred Payment Default) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
	loan	loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDRs Which Incurred Payment Default, Number of Loans	0	6
TDRs Which Incurred a Payment Default	$0	$1,026
Construction and land [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDRs Which Incurred Payment Default, Number of Loans	0	2
TDRs Which Incurred a Payment Default	0	483
Commercial business [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDRs Which Incurred Payment Default, Number of Loans	0	2
TDRs Which Incurred a Payment Default	0	321
One- to four-family residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDRs Which Incurred Payment Default, Number of Loans	0	2
TDRs Which Incurred a Payment Default	$0	$222

Recovered_Sheet3

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Risk-Rate and Non-Risk Rated Loans by Grade and Other Characteristic) (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	$3,833,820		$3,418,445
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	1,403,725		1,195,058
Multifamily Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	167,524		137,153
Construction and Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	411,006		351,258
Commercial business [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	723,964		682,169
Agricultural Business [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	238,499		228,291
One- to four-family residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	539,894		529,494
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	349,208		295,022
Pass (Risk Ratings 1-5) [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	3,737,037	[1]	3,308,889	[2]
Pass (Risk Ratings 1-5) [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	1,375,885	[1]	1,160,921	[2]
Pass (Risk Ratings 1-5) [Member] | Multifamily Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	166,712	[1]	131,523	[2]
Pass (Risk Ratings 1-5) [Member] | Construction and Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	395,356	[1]	332,150	[2]
Pass (Risk Ratings 1-5) [Member] | Commercial business [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	691,143	[1]	655,007	[2]
Pass (Risk Ratings 1-5) [Member] | Small Credit-Scored Business Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	115,000		94,000
Pass (Risk Ratings 1-5) [Member] | Agricultural Business [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	234,101	[1]	225,329	[2]
Pass (Risk Ratings 1-5) [Member] | One- to four-family residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	527,384	[1]	511,967	[2]
Pass (Risk Ratings 1-5) [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	346,456	[1]	291,992	[2]
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	32,428		18,115
Special Mention [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	3,717		6,614
Special Mention [Member] | Multifamily Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	0		0
Special Mention [Member] | Construction and Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	0		350
Special Mention [Member] | Commercial business [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	27,453		10,484
Special Mention [Member] | Agricultural Business [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	1,055		561
Special Mention [Member] | One- to four-family residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	63		0
Special Mention [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	140		106
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	64,344		90,888
Substandard [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	24,123		26,979
Substandard [Member] | Multifamily Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	812		5,630
Substandard [Member] | Construction and Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	15,650		18,758
Substandard [Member] | Commercial business [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	5,368		16,669
Substandard [Member] | Agricultural Business [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	3,343		2,401
Substandard [Member] | One- to four-family residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	12,447		17,527
Substandard [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	2,601		2,924
Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	11		553
Doubtful [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	0		544
Doubtful [Member] | Multifamily Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	0		0
Doubtful [Member] | Construction and Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	0		0
Doubtful [Member] | Commercial business [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	0		9
Doubtful [Member] | Agricultural Business [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	0		0
Doubtful [Member] | One- to four-family residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	0		0
Doubtful [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	11		0
Performing loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	3,817,084		3,393,677
Performing loans [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	1,402,328		1,188,771
Performing loans [Member] | Multifamily Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	167,524		137,153
Performing loans [Member] | Construction and Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	409,731		350,065
Performing loans [Member] | Commercial business [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	723,427		681,445
Performing loans [Member] | Agricultural Business [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	236,902		228,187
Performing loans [Member] | One- to four-family residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	529,292		514,351
Performing loans [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	347,880		293,705
Nonperforming loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	16,736	[3]	24,768	[3]
Nonperforming loans [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	1,397	[3]	6,287	[3]
Nonperforming loans [Member] | Multifamily Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	0	[3]	0	[3]
Nonperforming loans [Member] | Construction and Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	1,275	[3]	1,193	[3]
Nonperforming loans [Member] | Commercial business [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	537	[3]	724	[3]
Nonperforming loans [Member] | Agricultural Business [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	1,597	[3]	104	[3]
Nonperforming loans [Member] | One- to four-family residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	10,602	[3]	15,143	[3]
Nonperforming loans [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans outstanding	$1,328	[3]	$1,317	[3]
[1]	The Pass category includes some performing loans that are part of homogenous pools which are not individually risk-rated. This includes all consumer loans, all one- to four-family residential loans and, as of December 31, 2014, in the commercial business category, $115 million of credit-scored small business loans. As loans in these pools become non-performing, they are individually risk-rated.
[2]	The Pass category includes some performing loans that are part of homogenous pools which are not individually risk-rated. This includes all consumer loans, all one- to four-family residential loans and, as of December 31, 2013, in the commercial business category, $94 million of credit-scored small business loans. As loans in these pools become non-performing, they are individually risk-rated.
[3]	Non-performing loans include loans on non-accrual status and loans more than 90 days delinquent, but still accruing interest.

Recovered_Sheet4

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Age Analysis of Company's Past Due Loans) (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 to 59 Days Past Due	$5,037,000		$6,366,000
60 to 89 Days Past Due	4,256,000		4,086,000
90 Days or More Past Due	9,552,000		11,558,000
Total Past Due	18,845,000		22,010,000
Current	3,814,975,000		3,396,435,000
Total loans outstanding	3,833,820,000		3,418,445,000
Loans 90 Days or More Past Due and Accruing	2,175,000		2,860,000
Commerical real estate - owner-occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 to 59 Days Past Due	0		883,000
60 to 89 Days Past Due	1,984,000		550,000
90 Days or More Past Due	0		813,000
Total Past Due	1,984,000		2,246,000
Current	544,799,000		500,355,000
Total loans outstanding	546,783,000		502,601,000
Loans 90 Days or More Past Due and Accruing	0		0
Commerical real estate - investment properties [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 to 59 Days Past Due	639,000		0
60 to 89 Days Past Due	0		0
90 Days or More Past Due	0		0
Total Past Due	639,000		0
Current	856,303,000		692,457,000
Total loans outstanding	856,942,000		692,457,000
Loans 90 Days or More Past Due and Accruing	0		0
Multifamily real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 to 59 Days Past Due	0		1,845,000
60 to 89 Days Past Due	0		785,000
90 Days or More Past Due	0		0
Total Past Due	0		2,630,000
Current	167,524,000		134,523,000
Total loans outstanding	167,524,000		137,153,000
Loans 90 Days or More Past Due and Accruing	0		0
Commercial construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 to 59 Days Past Due	0		0
60 to 89 Days Past Due	0		0
90 Days or More Past Due	0		0
Total Past Due	0		0
Current	17,337,000		12,168,000
Total loans outstanding	17,337,000		12,168,000
Loans 90 Days or More Past Due and Accruing	0		0
Multifamily construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 to 59 Days Past Due	0		0
60 to 89 Days Past Due	0		0
90 Days or More Past Due	0		0
Total Past Due	0		0
Current	60,193,000		52,081,000
Total loans outstanding	60,193,000		52,081,000
Loans 90 Days or More Past Due and Accruing	0		0
One-to four-family construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 to 59 Days Past Due	840,000		9,000
60 to 89 Days Past Due	0		7,000
90 Days or More Past Due	0		4,000
Total Past Due	840,000		20,000
Current	219,049,000		200,844,000
Total loans outstanding	219,889,000		200,864,000
Loans 90 Days or More Past Due and Accruing	0		0
Land and land development - residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 to 59 Days Past Due	759,000		0
60 to 89 Days Past Due	0		0
90 Days or More Past Due	750,000		251,000
Total Past Due	1,509,000		251,000
Current	100,926,000		75,444,000
Total loans outstanding	102,435,000		75,695,000
Loans 90 Days or More Past Due and Accruing	0		0
Land and land development - commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 to 59 Days Past Due	0		0
60 to 89 Days Past Due	0		0
90 Days or More Past Due	0		0
Total Past Due	0		0
Current	11,152,000		10,450,000
Total loans outstanding	11,152,000		10,450,000
Loans 90 Days or More Past Due and Accruing	0		0
Commercial business [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 to 59 Days Past Due	775,000		2,001,000
60 to 89 Days Past Due	35,000		2,000
90 Days or More Past Due	100,000		299,000
Total Past Due	910,000		2,302,000
Current	723,054,000		679,867,000
Total loans outstanding	723,964,000		682,169,000
Loans 90 Days or More Past Due and Accruing	0		0
Agricultural business, including secured by farmland [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 to 59 Days Past Due	597,000		0
60 to 89 Days Past Due	466,000		0
90 Days or More Past Due	744,000		0
Total Past Due	1,807,000		0
Current	236,692,000		228,291,000
Total loans outstanding	238,499,000		228,291,000
Loans 90 Days or More Past Due and Accruing	0		105,000
One- to four-family residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 to 59 Days Past Due	877,000	[1]	521,000	[1]
60 to 89 Days Past Due	1,623,000		2,550,000
90 Days or More Past Due	7,526,000		9,142,000
Total Past Due	10,026,000		12,213,000
Current	529,868,000		517,281,000
Total loans outstanding	539,894,000		529,494,000
Loans 90 Days or More Past Due and Accruing	2,095,000		2,611,000
Exactly 30 Days Past Due, Not Included in Past Due Loans	8,000,000	[1]	6,000,000	[1]
Consumer secured by one- to four-family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 to 59 Days Past Due	59,000		723,000
60 to 89 Days Past Due	60,000		93,000
90 Days or More Past Due	139,000		918,000
Total Past Due	258,000		1,734,000
Current	221,947,000		171,454,000
Total loans outstanding	222,205,000		173,188,000
Loans 90 Days or More Past Due and Accruing	80,000		13,000
Consumer - other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 to 59 Days Past Due	491,000		384,000
60 to 89 Days Past Due	88,000		99,000
90 Days or More Past Due	293,000		131,000
Total Past Due	872,000		614,000
Current	126,131,000		121,220,000
Total loans outstanding	127,003,000		121,834,000
Loans 90 Days or More Past Due and Accruing	$0		$131,000
[1]	(1) One- to four-family loans are not considered past due until they exceed 30 days and are not reflected herein. One- to four-family loans exactly 30 days past due at December 31, 2014 and 2013 were $8 million and $6 million, respectively.

Recovered_Sheet5

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Allowance for Credit Losses) (Details) (USD $)	3 Months Ended												12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				$74,258				$76,759					$74,258	$76,759
Provision for loan losses	0	0	0	0	0	0	0	0	1,000	3,000	4,000	5,000	0	0	13,000
Recoveries													6,993	7,497
Charge-offs													-5,344	-9,998
Ending balance	75,907				74,258				76,759				75,907	74,258	76,759
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment	2,966				5,188								2,966	5,188
Allowance collectively evaluated for impairment	72,941				69,070								72,941	69,070
Total allowance for loan losses	75,907				74,258				76,759				75,907	74,258	76,759
Loans individually evaluated for impairment	34,446				60,647								34,446	60,647
Loans collectively evaluated for impairment	3,799,374				3,357,798								3,799,374	3,357,798
Total loans outstanding	3,833,820				3,418,445								3,833,820	3,418,445
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				16,759				15,322					16,759	15,322
Provision for loan losses													1,757	1,639
Recoveries													1,507	2,367
Charge-offs													-1,239	-2,569
Ending balance	18,784				16,759								18,784	16,759
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment	728				419								728	419
Allowance collectively evaluated for impairment	18,056				16,340								18,056	16,340
Total allowance for loan losses	18,784				16,759								18,784	16,759
Loans individually evaluated for impairment	7,171				10,877								7,171	10,877
Loans collectively evaluated for impairment	1,396,554				1,184,181								1,396,554	1,184,181
Total loans outstanding	1,403,725				1,195,058								1,403,725	1,195,058
Multifamily Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				5,306				4,506					5,306	4,506
Provision for loan losses													-724	800
Recoveries													0	0
Charge-offs													-20	0
Ending balance	4,562				5,306								4,562	5,306
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment	86				1,139								86	1,139
Allowance collectively evaluated for impairment	4,476				4,167								4,476	4,167
Total allowance for loan losses	4,562				5,306								4,562	5,306
Loans individually evaluated for impairment	786				5,744								786	5,744
Loans collectively evaluated for impairment	166,738				131,409								166,738	131,409
Total loans outstanding	167,524				137,153								167,524	137,153
Construction and Land [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				17,640				14,991					17,640	14,991
Provision for loan losses													6,336	2,195
Recoveries													1,776	2,275
Charge-offs													-207	-1,821
Ending balance	25,545				17,640								25,545	17,640
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment	986				1,762								986	1,762
Allowance collectively evaluated for impairment	24,559				15,878								24,559	15,878
Total allowance for loan losses	25,545				17,640								25,545	17,640
Loans individually evaluated for impairment	6,477				12,118								6,477	12,118
Loans collectively evaluated for impairment	404,529				339,140								404,529	339,140
Total loans outstanding	411,006				351,258								411,006	351,258
Commercial business [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				11,773				9,957					11,773	9,957
Provision for loan losses													626	1,925
Recoveries													988	1,673
Charge-offs													-1,344	-1,782
Ending balance	12,043				11,773								12,043	11,773
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment	82				222								82	222
Allowance collectively evaluated for impairment	11,961				11,551								11,961	11,551
Total allowance for loan losses	12,043				11,773								12,043	11,773
Loans individually evaluated for impairment	739				1,298								739	1,298
Loans collectively evaluated for impairment	723,225				680,871								723,225	680,871
Total loans outstanding	723,964				682,169								723,964	682,169
Agricultural Business [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				2,841				2,295					2,841	2,295
Provision for loan losses													-417	97
Recoveries													1,576	697
Charge-offs													-179	-248
Ending balance	3,821				2,841								3,821	2,841
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment	0				0								0	0
Allowance collectively evaluated for impairment	3,821				2,841								3,821	2,841
Total allowance for loan losses	3,821				2,841								3,821	2,841
Loans individually evaluated for impairment	744				0								744	0
Loans collectively evaluated for impairment	237,755				228,291								237,755	228,291
Total loans outstanding	238,499				228,291								238,499	228,291
One- to four-family residential [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				11,486				16,475					11,486	16,475
Provision for loan losses													-5,772	-2,995
Recoveries													618	145
Charge-offs													-885	-2,139
Ending balance	5,447				11,486								5,447	11,486
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment	1,014				1,579								1,014	1,579
Allowance collectively evaluated for impairment	4,433				9,907								4,433	9,907
Total allowance for loan losses	5,447				11,486								5,447	11,486
Loans individually evaluated for impairment	17,848				29,834								17,848	29,834
Loans collectively evaluated for impairment	522,046				499,660								522,046	499,660
Total loans outstanding	539,894				529,494								539,894	529,494
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				1,335				1,348					1,335	1,348
Provision for loan losses													90	1,086
Recoveries													528	340
Charge-offs													-1,470	-1,439
Ending balance	483				1,335								483	1,335
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment	70				67								70	67
Allowance collectively evaluated for impairment	413				1,268								413	1,268
Total allowance for loan losses	483				1,335								483	1,335
Loans individually evaluated for impairment	681				776								681	776
Loans collectively evaluated for impairment	348,527				294,246								348,527	294,246
Total loans outstanding	349,208				295,022								349,208	295,022
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				7,118				11,865					7,118	11,865
Provision for loan losses													-1,896	-4,747
Recoveries													0	0
Charge-offs													0	0
Ending balance	5,222				7,118								5,222	7,118
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment	0				0								0	0
Allowance collectively evaluated for impairment	5,222				7,118								5,222	7,118
Total allowance for loan losses	5,222				7,118								5,222	7,118
Loans individually evaluated for impairment	0				0								0	0
Loans collectively evaluated for impairment	0				0								0	0
Total loans outstanding	$0				$0								$0	$0

REAL_ESTATE_OWNED_HELD_FOR_SAL2

REAL ESTATE OWNED, HELD FOR SALE, NET (REO Rollforward) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Real Estate Owned [Roll Forward]
Balance, beginning of period	$4,044	$15,778	$42,965
Additions from loan foreclosures	3,264	3,166	13,930
Additions from capitalized costs	30	348	300
Proceeds from dispositions of REO	-4,923	-16,944	-40,965
Gain on sale of REO	973	2,481	4,725
Valuation adjustments in the period	-36	-785	-5,177
Balance, end of period	$3,352	$4,044	$15,778

REAL_ESTATE_OWNED_HELD_FOR_SAL3

REAL ESTATE OWNED, HELD FOR SALE, NET (REO by Type and Geographic Location by State) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Real Estate Owned [Line Items]
Total REO	$3,352	$4,044	$15,778	$42,965
Percent of total REO	100.00%
Washington [Member]
Real Estate Owned [Line Items]
Total REO	1,694
Percent of total REO	50.50%
Oregon [Member]
Real Estate Owned [Line Items]
Total REO	1,626
Percent of total REO	48.50%
Idaho [Member]
Real Estate Owned [Line Items]
Total REO	32
Percent of total REO	1.00%
Land development- residential [Member]
Real Estate Owned [Line Items]
Total REO	1,562
Land development- residential [Member] | Washington [Member]
Real Estate Owned [Line Items]
Total REO	259
Land development- residential [Member] | Oregon [Member]
Real Estate Owned [Line Items]
Total REO	1,271
Land development- residential [Member] | Idaho [Member]
Real Estate Owned [Line Items]
Total REO	32
One- to four-family real estate [Member]
Real Estate Owned [Line Items]
Total REO	1,790
One- to four-family real estate [Member] | Washington [Member]
Real Estate Owned [Line Items]
Total REO	1,435
One- to four-family real estate [Member] | Oregon [Member]
Real Estate Owned [Line Items]
Total REO	355
One- to four-family real estate [Member] | Idaho [Member]
Real Estate Owned [Line Items]
Total REO	$0

PROPERTY_AND_EQUIPMENT_NET_Det

PROPERTY AND EQUIPMENT, NET (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Property, Plant and Equipment [Abstract]
Land	$21,969	$19,974
Buildings and leasehold improvements	98,901	99,351
Furniture and equipment	72,152	65,912
Property and equipment, gross	193,022	185,237
Less accumulated depreciation	-101,837	-94,970
Property and equipment, net	$91,185	$90,267

PROPERTY_AND_EQUIPMENT_NET_Ope

PROPERTY AND EQUIPMENT, NET (Operating Lease Commitments) (Details) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Property, Plant and Equipment [Abstract]
2015	$7.60
2016	5.7
2017	4.7
2018	4.2
2019	3.4
Thereafter	9.6
Total	$35.20

PROPERTY_AND_EQUIPMENT_NET_PRO

PROPERTY AND EQUIPMENT, NET PROPERTY AND EQUIPMENT, NET (Textual) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Abstract]
Depreciation expense	$8,064,000	$7,457,000	$7,788,000
Rental expense	$7,600,000	$7,300,000	$7,100,000

DEPOSITS_Deposit_Liabilities_D

DEPOSITS (Deposit Liabilities) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Deposit Liabilities [Line Items]
Non-interest-bearing checking	$1,298,866,000	$1,115,346,000
Interest-bearing checking	439,480,000	422,910,000
Regular savings accounts	901,142,000	798,764,000
Money market accounts	488,946,000	408,211,000
Total transaction and savings accounts	3,128,434,000	2,745,231,000
Non-interest-bearing accounts, percent of total	33.30%	30.80%
Interest-bearing checking, percent of total	11.30%	11.70%
Regular savings accounts, percent of total	23.10%	22.10%
Money market accounts, percent of total	12.50%	11.30%
Total transaction and saving accounts, percent of total	80.20%	75.90%
Certificates of deposit:
Total certificates of deposit	770,516,000	872,695,000
Total certificate accounts, percent of total	19.80%	24.10%
Total deposits	3,898,950,000	3,617,926,000	3,557,804,000	3,475,654,000
Total deposits, percent of total	100.00%	100.00%
Included in total deposits:
Public fund transaction accounts	102,854,000	87,521,000
Public fund interest-bearing certificates	35,346,000	51,465,000
Total public deposits	138,200,000	138,986,000
Public fund transaction accounts, percent of total	2.60%	2.40%
Public fund interest-bearing certificates, percent of total	0.90%	1.40%
Total public deposits, percent of total	3.50%	3.80%
Total brokered deposits	4,799,000	4,291,000
Total brokered deposits, percent of total	0.10%	0.10%
Related Party Deposit Liabilities	6,200,000	6,700,000
Up to 1.00% [Member]
Certificates of deposit:
Total certificates of deposit	643,065,000	723,891,000
Total certificate accounts, percent of total	16.50%	20.00%
Included in total deposits:
Certificates of deposit, interest rate, upper range limit	1.00%
1.01% to 2.00% [Member]
Certificates of deposit:
Total certificates of deposit	87,661,000	95,663,000
Total certificate accounts, percent of total	2.30%	2.60%
Included in total deposits:
Certificates of deposit, interest rate, lower range limit	1.01%
Certificates of deposit, interest rate, upper range limit	2.00%
2.01% to 3.00% [Member]
Certificates of deposit:
Total certificates of deposit	32,184,000	43,062,000
Total certificate accounts, percent of total	0.80%	1.20%
Included in total deposits:
Certificates of deposit, interest rate, lower range limit	2.01%
Certificates of deposit, interest rate, upper range limit	3.00%
3.01% to 4.00% [Member]
Certificates of deposit:
Total certificates of deposit	3,024,000	6,663,000
Total certificate accounts, percent of total	0.10%	0.20%
Included in total deposits:
Certificates of deposit, interest rate, lower range limit	3.01%
Certificates of deposit, interest rate, upper range limit	4.00%
4.01% and greater [Member]
Certificates of deposit:
Total certificates of deposit	$4,582,000	$3,416,000
Total certificate accounts, percent of total	0.10%	0.10%
Included in total deposits:
Certificates of deposit, interest rate, lower range limit	4.01%

DEPOSITS_DEPOSITS_Certificates

DEPOSITS DEPOSITS (Certificates of Deposit by Balance) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Time Deposits [Abstract]
Certificates of deposit less than $100,000	$358,189,000	$386,745,000
Certificates of deposit $100,000 through $250,000	275,156,000	308,130,000
Certificates of deposit more than $250,000	137,171,000	177,820,000
Total certificates of deposit	770,516,000	872,695,000
Certificates of deposit $250,000 or more	$141,000,000	$184,000,000

DEPOSITS_Maturities_and_Weight

DEPOSITS (Maturities and Weighted Average Interest Rates of Certificates of Deposit) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Maturities of Time Deposits [Abstract]
Maturing in one year or less	$564,501	$660,394
Maturing after one year through two years	117,724	117,789
Maturing after two years through three years	46,378	47,362
Maturing after three years through four years	20,016	26,443
Maturing after four years through five years	17,338	17,075
Maturing after five years	4,559	3,632
Total certificates of deposit	$770,516	$872,695
Weighted Average Rate [Abstract]
Maturing in one year or less	0.46%	0.47%
Maturing after one year through two years	0.89%	1.05%
Maturing after two years through three years	1.19%	1.34%
Maturing after three years through four years	1.42%	1.56%
Maturing after four years through five years	1.22%	1.34%
Maturing after five years	2.09%	1.78%
Total certificates of deposits	1.06%	0.65%

DEPOSITS_Deposit_Liabilities_A

DEPOSITS (Deposit Liabilities Activities) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Deposit Activity [Roll Forward]
Balance at beginning of year	$3,617,926	$3,557,804	$3,475,654
Net increase before interest credited	273,446	50,385	67,043
Interest credited	7,578	9,737	15,107
Net increase (decrease) in deposits	281,024	60,122	82,150
Balance at end of year	$3,898,950	$3,617,926	$3,557,804

DEPOSITS_Interest_Expense_Depo

DEPOSITS (Interest Expense Deposit Liabilities by Type) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Banking and Thrift [Abstract]
Certificates of deposit (1)	$5,145,000	[1]	$6,836,000	[1]	$11,458,000	[1]
Demand, interest-bearing checking and money market accounts	1,123,000		1,329,000		1,824,000
Regular savings	1,310,000		1,572,000		1,825,000
Total interest expense	7,578,000		9,737,000		15,107,000
Certificates of deposit, $100,000 or more	$3,100,000		$4,000,000		$6,700,000
[1]	(1) Interest expense on certificate of deposit accounts with balances of $100,000 or more totaled $3.1 million, $4.0 million, and $6.7 million for the years ended December 31, 2014, 2013 and 2012, respectively.

ADVANCES_FROM_FEDERAL_HOME_LOA2

ADVANCES FROM FEDERAL HOME LOAN BANK OF SEATTLE (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Amount:
Maturing in one year or less	$32,000,000	$27,000,000
Maturing after one year through three years	0	0
Maturing after three years through five years	0	0
Maturing after five years	196,000	203,000
Total FHLB advances, at par	32,196,000	27,203,000	10,210,000
Fair value adjustment	54,000	47,000
Total FHLB advances, carried at fair value	32,250,000	27,250,000
Weighted Average Rate:
Maturing in one year or less, weighted average rate	0.27%	0.23%
Maturing after one year through three years, weighted average rate	0.00%	0.00%
Maturing after three years through five years, weighted average rate	0.00%	0.00%
Maturing after five years, weighted average rate	5.94%	5.94%
Total FHLB advances, at par, weighted average rate	0.27%	0.27%	2.45%
Federal Home Loan Bank, Advances, Activity for Year [Abstract]
Maximum outstanding at any month end, at par	105,450,000	60,377,000	10,216,000
Average outstanding, at par	39,121,000	18,935,000	10,215,000
Year-end outstanding, at par	32,196,000	27,203,000	10,210,000
Weighted average interest rate, annual	0.32%	0.52%	2.49%
Weighted average interest rate, end of period	0.27%	0.27%	2.45%
Interest expense during the period	125,000	99,000	254,000
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	901,000,000
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	$23,000,000

OTHER_BORROWINGS_Schedule_of_O

OTHER BORROWINGS (Schedule of Other Borrowings) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Amount:
Total year-end outstanding	$77,185	$83,056
Repurchase Agreements [Member] | Retail repurchase agreements [Member]
Amount:
Maturing in one year or less	77,185	83,056
Maturing after one year through two years	0	0
Maturing after two years	0	0
Total year-end outstanding	77,185	83,056
Weighted Average Rate:
Maturing in one year or less, weighted average interest rate	0.20%	0.20%
Maturing after one year through two years, weighted average interest rate	0.00%	0.00%
Maturing after two years, weighted average interest rate	0.00%	0.00%
Total year-end outstanding, weighted average interest rate	0.20%	0.20%
Other Borrowings, Activity for Year [Abstract]
Average outstanding	83,965	84,877
Average outstanding, weighted average interest rate	0.20%	0.23%
Maximum outstanding at any month end	$89,921	$91,964

OTHER_BORROWINGS_Schedule_of_I

OTHER BORROWINGS (Schedule of Interest Expense) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Debt Disclosure [Abstract]
Retail repurchase agreements	$172	$192	$281
FDIC guaranteed debt	0	0	477
Total expense	$172	$192	$758

OTHER_BORROWINGS_Textuals_Deta

OTHER BORROWINGS (Textuals) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Securities pledged to secure retail repurchase agreements	$98,735,000
Funds Borrowed Against Current Borrowing Capacity	77,185,000	83,056,000
Repurchase Agreements [Member] | Retail repurchase agreements [Member]
Debt Instrument [Line Items]
Funds Borrowed Against Current Borrowing Capacity	77,185,000	83,056,000
Repurchase Agreements [Member] | Retail repurchase agreements [Member] | Minimum [Member]
Debt Instrument [Line Items]
Repurchase agreements, interest rate	0.15%
Repurchase Agreements [Member] | Retail repurchase agreements [Member] | Maximum [Member]
Debt Instrument [Line Items]
Repurchase agreements, interest rate	0.40%
Federal Reserve Bank Advances [Member] | Federal Reserve Bank of San Francisco [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity	639,000,000
Funds Borrowed Against Current Borrowing Capacity	$0	$0

JUNIOR_SUBORDINATED_DEBENTURES2

JUNIOR SUBORDINATED DEBENTURES AND MANDATORILY REDEEMABLE TRUST PREFERRED SECURITIES (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Schedule of Trust Preferred Securities [Line Items]
Number of wholly-owned Grantor Trusts	6
Grantor trusts amount of tier one risk based capital	$633,317	$584,838
Debentures Subject to Mandatory Redemption [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	123,716
Fair value adjustment	-45,715
Total TPS liability at fair value	78,001
Current Interest Rate	2.32%
Debentures Subject to Mandatory Redemption [Member] | Banner Capital Trusts [Member]
Schedule of Trust Preferred Securities [Line Items]
Grantor trusts amount of tier one risk based capital	74,300
Grantor trusts percentage of tier one risk based capital	11.80%
Debentures Subject to Mandatory Redemption [Member] | Banner Capital Trust II [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	15,464
Current Interest Rate	3.58%
Interest Rate Spread, Description	Three-month LIBOR
Interest Rate Spread	3.35%
Interest Deferral Period	5 years
Debentures Subject to Mandatory Redemption [Member] | Banner Capital Trust III [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	15,465
Current Interest Rate	3.13%
Interest Rate Spread, Description	Three-month LIBOR
Interest Rate Spread	2.90%
Interest Deferral Period	5 years
Debentures Subject to Mandatory Redemption [Member] | Banner Capital Trust IV [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	15,465
Current Interest Rate	3.08%
Interest Rate Spread, Description	Three-month LIBOR
Interest Rate Spread	2.85%
Interest Deferral Period	5 years
Debentures Subject to Mandatory Redemption [Member] | Banner Capital Trust V [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	25,774
Current Interest Rate	1.80%
Interest Rate Spread, Description	Three-month LIBOR
Interest Rate Spread	1.57%
Interest Deferral Period	5 years
Debentures Subject to Mandatory Redemption [Member] | Banner Capital Trust VI [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	25,774
Current Interest Rate	1.86%
Interest Rate Spread, Description	Three-month LIBOR
Interest Rate Spread	1.62%
Interest Deferral Period	5 years
Debentures Subject to Mandatory Redemption [Member] | Banner Capital Trust VII [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	25,774
Current Interest Rate	1.62%
Interest Rate Spread, Description	Three-month LIBOR
Interest Rate Spread	1.38%
Interest Deferral Period	5 years
Aggregate Liquidation Amount of Trust Preferred Securities [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	120,000
Aggregate Liquidation Amount of Trust Preferred Securities [Member] | Banner Capital Trust II [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	15,000
Aggregate Liquidation Amount of Trust Preferred Securities [Member] | Banner Capital Trust III [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	15,000
Aggregate Liquidation Amount of Trust Preferred Securities [Member] | Banner Capital Trust IV [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	15,000
Aggregate Liquidation Amount of Trust Preferred Securities [Member] | Banner Capital Trust V [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	25,000
Aggregate Liquidation Amount of Trust Preferred Securities [Member] | Banner Capital Trust VI [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	25,000
Aggregate Liquidation Amount of Trust Preferred Securities [Member] | Banner Capital Trust VII [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	25,000
Aggregate Liquidation Amount of Common Capital Securities [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	3,716
Aggregate Liquidation Amount of Common Capital Securities [Member] | Banner Capital Trust II [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	464
Aggregate Liquidation Amount of Common Capital Securities [Member] | Banner Capital Trust III [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	465
Aggregate Liquidation Amount of Common Capital Securities [Member] | Banner Capital Trust IV [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	465
Aggregate Liquidation Amount of Common Capital Securities [Member] | Banner Capital Trust V [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	774
Aggregate Liquidation Amount of Common Capital Securities [Member] | Banner Capital Trust VI [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	774
Aggregate Liquidation Amount of Common Capital Securities [Member] | Banner Capital Trust VII [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	$774

INCOME_TAXES_Components_of_Inc

INCOME TAXES (Components of Income Tax Expense (Benefit)) (Details) (USD $)	3 Months Ended												12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Current													$24,855	$12,121	$10,759
Deferred													1,365	10,407	841
Increase (decrease) in valuation allowance													0	0	-36,385
Provision for (benefit from) income taxes	$5,599	$7,076	$8,499	$5,046	$5,704	$5,880	$5,661	$5,284	$4,638	$2,407	($31,830)	$0	$26,220	$22,528	($24,785)

INCOME_TAXES_Effective_Income_

INCOME TAXES (Effective Income Tax Rate Reconciliation) (Details) (USD $)	3 Months Ended												12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Provision for (benefit from) income taxes computed at federal statutory rate													$28,134	$24,179	$14,034
Increase (decrease) in taxes due to:
Tax-exempt interest													-2,084	-1,633	-1,710
Investment in life insurance													-626	-707	-894
State income taxes (benefit), net of federal tax offset													916	824	539
Tax credits													-661	-636	-788
Valuation allowance													0	0	-36,385
Other													541	501	419
Provision for (benefit from) income taxes	$5,599	$7,076	$8,499	$5,046	$5,704	$5,880	$5,661	$5,284	$4,638	$2,407	($31,830)	$0	$26,220	$22,528	($24,785)
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Federal income tax statutory rate													35.00%	35.00%	35.00%
Increase (decrease) in tax rate due to:
Tax-exempt interest													-2.60%	-2.40%	-4.30%
Investment in life insurance													-0.80%	-1.00%	-2.20%
State income taxes (benefit), net of federal tax offset													1.10%	1.20%	1.30%
Tax credits													-0.80%	-0.90%	-2.00%
Valuation allowance													0.00%	0.00%	-90.70%
Other													0.70%	0.70%	1.10%
Effective income tax rate													32.60%	32.60%	-61.80%

INCOME_TAXES_Schedule_of_Net_D

INCOME TAXES (Schedule of Net Deferred Tax Asset ) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred tax assets:
REO and loan loss reserves	$26,536	$17,326
Deferred compensation	9,223	7,305
Net operating loss carryforward	17,577	27,639
Low income housing tax credits	3,676	3,676
State net operating losses	1,009	957
Other	1,344	1,235
Total deferred tax assets	59,365	58,138
Deferred tax liabilities:
FHLB stock dividends	-4,805	-5,875
Depreciation	-4,479	-4,074
Deferred loan fees, servicing rights and loan origination costs	7,843	6,444
Intangibles	-975	-833
Financial instruments accounted for under fair value accounting	-15,611	-15,118
Loan discount	-1,190	0
Total deferred tax liabilities	-34,903	-32,344
Deferred income tax asset	24,462	25,794
Unrealized loss on securities—available-for-sale	145	1,685
Deferred tax asset, net	$24,607	$27,479

INCOME_TAXES_Textuals_Details

INCOME TAXES (Textuals) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Operating Loss Carryforwards [Line Items]
Operating loss carryforward, amount expected to be utilized on an annual basis	$6,900,000
Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	50,200,000	79,000,000
Tax basis bad debt reserves for which no income tax liability has been booked	5,400,000	5,400,000
Unrecognized deferred tax liability related to bad debt reserves	1,900,000
Internal Revenue Service (IRS) [Member] | General Business Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Federal and state tax credit carryforwards	2,700,000	2,700,000
Internal Revenue Service (IRS) [Member] | Alternative Minimum Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Federal and state tax credit carryforwards	900,000	900,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	21,200,000	20,400,000
Maximum [Member] | Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards [Line Items]
Refund due from amended federal income tax returns	$0	$9,800,000

EMPLOYEE_BENEFIT_PLANS_Details

EMPLOYEE BENEFIT PLANS (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Defined contribution plan expense	$1,400,000	$1,000,000	$43,000
Defined contribution plan, employer matching contribution percent	4.00%
Deferred compensation liability	16,807,000	16,442,000
Carrying value of shares held in trust for stock related compensation plans	6,669,000	7,063,000
Cash surrender value of bank-owned life insurance policies	63,800,000	61,900,000
Supplemental Retirement and Salary Contribution Plans [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred compensation plans expense	1,200,000	1,500,000	879,000
Deferred compensation liability	14,200,000	13,600,000
Deferred Cpmpensation Plans and Rabbi Trusts [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred compensation liability	8,200,000	8,500,000
Carrying value of shares held in trust for stock related compensation plans	6,700,000	7,100,000
Shares held in Treasury for future payment	$6,700,000	$7,100,000

EMPLOYEE_STOCK_OWNERSHIP_PLAN_1

EMPLOYEE STOCK OWNERSHIP PLAN AND TRUST (Details) (Employer Stock Ownership Plan and Trust [Member], USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 1995
Employer Stock Ownership Plan and Trust [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Employer loan, original amount			$8,700,000
ESOP contributions	0	0
ESOP payments	$0	$0

STOCKBASED_COMPENSATION_PLANS_1

STOCK-BASED COMPENSATION PLANS (Restricted Stock Activity) (Details) (Restricted Stock [Member], USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Restricted Stock [Member]
Unvested Shares: [Roll Forward]
Unvested, Beginning Balance	164,492	107,851	28,735
Granted	90,181	98,891	92,035
Vested	-56,307	-42,250	-11,419
Forfeited	-3,260	0	-1,500
Unvested, Ending Balance	195,106	164,492	107,851
Weighted Average Grant-Date Fair Value (in dollars per share):
Unvested, Beginning Balance	$26.94	$20.59	$14.50
Granted	$40.07	$30.81	$21.77
Vested	$24.81	$19.85	$14.60
Forfeited	$31	$0	$21.94
Unvested, Ending Balance	$32.83	$26.94	$20.59

STOCKBASED_COMPENSATION_PLANS_2

STOCK-BASED COMPENSATION PLANS (Stock Option Award Activity) (Details) (SOPs [Member], Stock Options [Member], USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
SOPs [Member] | Stock Options [Member]
Stock Options Outstanding Shares:
Outstanding, beginning of the year	26,364	42,521	51,729
Granted	0	0	0
Exercised	0	0	0
Forfeited	-15,700	-16,157	-9,208
Outstanding, end of the year	10,664	26,364	42,521	51,729
Outstanding at end of year, net of expected forfeitures, shares	0
Exercisable at end of year, shares	10,664
Stock Options Outstanding Weighted Average Exercise Price (in dollars per share):
Outstanding, beginning of the year	$206.27	$173.98	$168.98
Granted	$0	$0	$0
Exercised	$0	$0	$0
Forfeited	$206.44	$121.29	$145.97
Outstanding, end of the year	$206.03	$206.27	$173.98	$168.98
Outstanding end of year, net of expected forfeitures, weighted average exercise price	$0
Exercisable end of year, weighted average exercise price	$206.03
Weighted Average Remaining Contractual Term, In Years:
Outstanding, end of year	1 year 10 months 26 days	1 year 7 months	1 year 9 months	2 years 4 months 26 days
Exercisable, end of year	1 year 10 months 26 days

STOCKBASED_COMPENSATION_PLANS_3

STOCK-BASED COMPENSATION PLANS (Financial Data Pertaining to Outstanding Stock Options) (Details) (SOPs [Member], Stock Options [Member], USD $)	12 Months Ended
	Dec. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Weighted Average Exercise Price of Option Shares Granted	$206.44
Number of Option Shares Granted	10,664
Weighted Average Option Shares Vested and Exercisable	10,664
Weighted Average Exercise Price of Option Shares Exercisable	$206.27
$0.00 to $184.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower	$0
Exercise Price, Upper	$184
Weighted Average Exercise Price of Option Shares Granted	$176.72
Number of Option Shares Granted	2,593
Weighted Average Option Shares Vested and Exercisable	2,593
Weighted Average Exercise Price of Option Shares Exercisable	$176.72
Remaining Contractual Life	29 days
$184.01 to $220.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower	$184.01
Exercise Price, Upper	$220
Weighted Average Exercise Price of Option Shares Granted	$212.96
Number of Option Shares Granted	8,071
Weighted Average Option Shares Vested and Exercisable	8,071
Weighted Average Exercise Price of Option Shares Exercisable	$212.96
Remaining Contractual Life	1 year 9 months 22 days

STOCKBASED_COMPENSATION_PLANS_4

STOCK-BASED COMPENSATION PLANS (Stock-based Compensation Costs) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Salary and employee benefits	$0	$0	$11
Decrease in provision for income taxes	0	0	-4
Decrease in equity, net	$0	$0	$7

STOCKBASED_COMPENSATION_PLANS_5

STOCK-BASED COMPENSATION PLANS (Textuals) (Details) (USD $)	12 Months Ended			0 Months Ended	32 Months Ended	9 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Apr. 24, 2012	Dec. 31, 2014	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$0	$0	$11,000
Deferred compensation liability	16,807,000	16,442,000			16,807,000	16,807,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted in period	90,181	98,891	92,035
Stock-based compensation expense	2,700,000	1,500,000	434,000
Unrecognized compensation expense	3,900,000				3,900,000	3,900,000
Unrecognized compensation expense, period for recognition	30 months
2012 Restricted Stock and Incentive Bonus Plan [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized	300,000				300,000	300,000
Award vesting period				3 years
Plan maximum contractual term				10 years
Shares granted in period					266,778
SOPs [Member] | Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized	2,284,186				2,284,186	2,284,186
Stock-based compensation expense	0	0	7,000,000
Stock Options Exercised	0	0	0
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
Stock options granted in period	0	0	0
Banner Corporation Long-Term Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	89,000	1,000,000	314,000
Deferred compensation liability	$1,100,000				1,100,000	1,100,000
2014 Omnibus Incentive Plan [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized	900,000				900,000	900,000
Shares granted in period						9,352
Chief Executive Officer [Member] | 2012 Restricted Stock and Incentive Bonus Plan [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of increments shares vest annually	3

PREFERRED_STOCK_AND_RELATED_WA1

PREFERRED STOCK AND RELATED WARRANT (Details) (USD $)	0 Months Ended
	Nov. 21, 2008	Dec. 31, 2014	Dec. 31, 2013	Mar. 29, 2012
Class of Stock [Line Items]
Common stock, par value per share		$0.01	$0.01
Preferred stock issued, value		$0	$0
U.S. Treasury Capital Purchase Program [Member] | Series A Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares issued	124,000
Preferred stock, liquidation value per share	$1,000
Preferred stock aggregate liquidation preference	124,000,000
Preferred stock issued, value				124,000,000
U.S. Treasury Capital Purchase Program [Member] | Common Stock [Member] | Warrant [Member]
Class of Stock [Line Items]
U.S. Treasury warrants, term (in years)	10 years
Warrant, option to purchase common stock (in shares)	243,998
Common stock, par value per share	$0.01
U.S. Treasury warrants, exercise price per share	$76.23
U.S. Treasury warrants, aggregate exercise price	$18,600,000

REGULATORY_CAPITAL_REQUIREMENT2

REGULATORY CAPITAL REQUIREMENTS (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Total capital to risk-weighted assets:
Actual	$684,583	$631,674
Actual, Ratio	16.80%	16.99%
Minimum for Capital Adequacy Purposes	326,071	297,493
Minimum for Capital Adequacy Purposes, Ratio	8.00%	8.00%
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	10.00%
Tier 1 capital to risk-weighted assets:
Actual	633,317	584,838
Actual, Ratio	15.54%	15.73%
Minimum for Capital Adequacy Purposes	163,036	148,747
Minimum for Capital Adequacy Purposes, Ratio	4.00%	4.00%
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	6.00%
Tier 1 leverage capital to average assets:
Actual	633,317	584,838
Actual, Ratio	13.41%	13.64%
Minimum for Capital Adequacy Purposes	188,885	171,553
Minimum for Capital Adequacy Purposes, Ratio	4.00%	4.00%
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	5.00%
Banner Bank [Member]
Total capital to risk-weighted assets:
Actual	605,997	557,253
Actual, Ratio	15.53%	15.75%
Minimum for Capital Adequacy Purposes	312,220	282,984
Minimum for Capital Adequacy Purposes, Ratio	8.00%	8.00%
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions	390,274	353,730
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	10.00%	10.00%
Tier 1 capital to risk-weighted assets:
Actual	556,897	512,689
Actual, Ratio	14.27%	14.49%
Minimum for Capital Adequacy Purposes	156,110	141,192
Minimum for Capital Adequacy Purposes, Ratio	4.00%	4.00%
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions	234,165	212,238
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	6.00%	6.00%
Tier 1 leverage capital to average assets:
Actual	556,897	512,689
Actual, Ratio	12.42%	12.65%
Minimum for Capital Adequacy Purposes	179,304	162,174
Minimum for Capital Adequacy Purposes, Ratio	4.00%	4.00%
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions	224,130	202,707
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	5.00%	5.00%
Islanders Bank
Total capital to risk-weighted assets:
Actual	36,590	34,795
Actual, Ratio	19.92%	18.73%
Minimum for Capital Adequacy Purposes	14,693	14,859
Minimum for Capital Adequacy Purposes, Ratio	8.00%	8.00%
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions	18,367	18,574
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	10.00%	10.00%
Tier 1 capital to risk-weighted assets:
Actual	34,332	32,469
Actual, Ratio	18.69%	17.48%
Minimum for Capital Adequacy Purposes	7,347	7,430
Minimum for Capital Adequacy Purposes, Ratio	4.00%	4.00%
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions	11,020	11,144
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	6.00%	6.00%
Tier 1 leverage capital to average assets:
Actual	34,332	32,469
Actual, Ratio	13.68%	13.60%
Minimum for Capital Adequacy Purposes	10,040	9,553
Minimum for Capital Adequacy Purposes, Ratio	4.00%	4.00%
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions	$12,550	$11,941
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	5.00%	5.00%

CONTINGENCIES_Details

CONTINGENCIES (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Collateralization Requirements for Public Funds [Line Items]
Public deposits	138,200	$138,986
Washington [Member]
Collateralization Requirements for Public Funds [Line Items]
Maximum liability percentage for uninsured public funds	10.00%
Required percentage collaterlization	100.00%
Minimum [Member] | Oregon [Member]
Collateralization Requirements for Public Funds [Line Items]
Required percentage collaterlization	50.00%
Maximum [Member] | Oregon [Member]
Collateralization Requirements for Public Funds [Line Items]
Required percentage collaterlization	110.00%

OTHER_INTANGIBLE_ASSETS_AND_MO2

OTHER INTANGIBLE ASSETS AND MORTGAGE SERVICING RIGHTS (Finite-Lived Intangible Assets) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2007
				acquisition
Finite-Lived Intangible Assets [Line Items]
Number of bank acquisitions				3
Finite-lived Intangible Assets [Roll Forward]
Balance, beginning of period	$2,449	$4,230	$6,331
Additions through acquisition	2,372	160
Amortization	-1,990	-1,941	-2,101
Balance, end of period	2,831	2,449	4,230
Core Deposit Intangibles [Member]
Finite-lived Intangible Assets [Roll Forward]
Balance, beginning of period	2,449	4,230	6,322
Additions through acquisition	2,372	160
Amortization	-1,990	-1,941	-2,092
Balance, end of period	2,831	2,449	4,230
Other [Member]
Finite-lived Intangible Assets [Roll Forward]
Balance, beginning of period	0	0	9
Additions through acquisition	0	0
Amortization	0	0	-9
Balance, end of period	$0	$0	$0
Minimum [Member] | Core Deposit Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible asset, useful life	3 years
Maximum [Member] | Core Deposit Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible asset, useful life	8 years

OTHER_INTANGIBLE_ASSETS_AND_MO3

OTHER INTANGIBLE ASSETS AND MORTGAGE SERVICING RIGHTS (Estimated Annual Amortization Expense) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets [Line Items]
Year Ended December 31, 2015	$1,007
Year Ended December 31, 2016	353
Year Ended December 31, 2017	321
Year Ended December 31, 2018	296
Thereafter	854
Net carrying amount	2,831	2,449	4,230	6,331
Core Deposit Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Net carrying amount	2,831	2,449	4,230	6,322
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Net carrying amount	$0	$0	$0	$9

OTHER_INTANGIBLE_ASSETS_AND_MO4

OTHER INTANGIBLE ASSETS AND MORTGAGE SERVICING RIGHTS (Mortgage Servicing Rights) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Serviced Loans
Servicing Assets at Amortized Value [Line Items]
Loans serviced for others	$1,391,000,000		$1,216,000,000
Mortgage Servicing Rights
Servicing Assets at Amortized Value [Line Items]
Custodial accounts	6,700,000		5,700,000
Servicing Asset at Amortized Value, Balance [Roll Forward]
Balance, beginning of the year	8,086,000	[1]	6,244,000	[1]	5,584,000
Amounts capitalized	3,023,000	[2]	2,913,000	[2]	3,662,000	[2]
Amortization	-2,079,000		-2,371,000		-2,602,000
Valuation adjustments in the period	0		-1,300,000		-400,000
Balance, end of the year	9,030,000	[1]	8,086,000	[1]	6,244,000	[1]
Valuation Allowance	$0		$0		$1,300,000
[1]	Balances as of December 31, 2014 and 2013 are net of no valuation allowances, and as of December 31, 2012 are net of a $1.3 million valuation allowance.
[2]	Amortization of mortgage servicing rights is recorded as a reduction of loan servicing income and any unamortized balance is fully written off if the loan repays in full.

FAIR_VALUE_OF_FINANCIAL_INSTRU2

FAIR VALUE OF FINANCIAL INSTRUMENTS (Asset Inputs) (Details) (USD $)	12 Months Ended			3 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014	Dec. 31, 2011
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Securities—trading, amortized cost basis	$47,480	$75,150		$47,480
TRUP CDO Securities [Member] | Level 3 [Member] | Income Approach Valuation Technique [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Securities—trading, amortized cost basis	10,000			10,000
Fair value gain	4,900	-255	3,300
TPS Securities [Member] | Level 3 [Member] | Income Approach Valuation Technique [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value inputs, discount rate, description of variable rate basis	three-month LIBOR
Fair value inputs, discount rate, basis spread on variable rate basis	5.00%	5.25%	5.25%	5.00%
Securities—trading, amortized cost basis	19,000			19,000
Fair value gain		$74	$578	$35
TPS Securities [Member] | Minimum [Member] | Level 3 [Member] | Income Approach Valuation Technique [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value inputs, discount rate, basis spread on variable rate basis					6.00%
TPS Securities [Member] | Maximum [Member] | Level 3 [Member] | Income Approach Valuation Technique [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value inputs, discount rate, basis spread on variable rate basis					8.00%

FAIR_VALUE_OF_FINANCIAL_INSTRU3

FAIR VALUE OF FINANCIAL INSTRUMENTS (Liability Inputs) (Details) (USD $)	12 Months Ended		3 Months Ended				12 Months Ended	3 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2012	Dec. 31, 2014	Mar. 31, 2012
Junior Subordinated Debentures [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair value gain (loss)	($4,073)	($865)
Junior Subordinated Debentures [Member] | Junior Subordinated Debentures with Variable Interest Rates Which Reset Quarterly [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Junior subordinated debentures, description of variable rate basis	three-month LIBOR
Level 3 [Member] | Income Approach Valuation Technique [Member] | Junior Subordinated Debentures [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Fair value inputs, discount rate, description of variable rate basis	three-month LIBOR	three-month LIBOR	three-month LIBOR	three-month LIBOR	three-month LIBOR	LIBOR
Fair value inputs, discount rate, basis spread on variable rate basis	5.00%	5.25%	5.25%		5.25%	5.50%		5.00%	8.00%
Fair value gain (loss)	($4,100)	($865)					($23,100)
Minimum [Member] | Level 3 [Member] | Income Approach Valuation Technique [Member] | Junior Subordinated Debentures with Variable Interest Rates Which Reset Quarterly [Member] | Junior Subordinated Debentures [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Junior subordinated debentures, variable rate								1.38%
Maximum [Member] | Level 3 [Member] | Income Approach Valuation Technique [Member] | Junior Subordinated Debentures with Variable Interest Rates Which Reset Quarterly [Member] | Junior Subordinated Debentures [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Junior subordinated debentures, variable rate								3.35%

FAIR_VALUE_OF_FINANCIAL_INSTRU4

FAIR VALUE OF FINANCIAL INSTRUMENTS (Assets and Liabilities Measured at Fair Value) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	$411,021	$470,280
Securities—trading, Fair Value	40,258	62,472
Advances from FHLB at fair value	32,250	27,250
Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	411,021	470,280
Securities—trading, Fair Value	40,258	62,472
Total assets	457,886	537,828
Advances from FHLB at fair value	32,250	27,250
Junior subordinated debentures net of unamortized deferred issuance costs at fair value	78,001	73,928
Total liabilities	116,739	106,167
Recurring [Member] | U.S. Government and agency [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	29,770	58,660
Securities—trading, Fair Value	1,505	1,481
Recurring [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	50,028	52,855
Securities—trading, Fair Value	1,440	5,023
Recurring [Member] | Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	5,018	6,964
Recurring [Member] | TPS and TRUP CDOs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading, Fair Value	19,118	35,140
Recurring [Member] | Mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	300,810	326,610
Securities—trading, Fair Value	18,136	20,760
Recurring [Member] | Asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	25,395	25,191
Recurring [Member] | Equity securities and other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading, Fair Value	59	68
Recurring [Member] | Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	317	130
Derivative liabilities	198	43
Recurring [Member] | Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	6,290	4,946
Derivative liabilities	6,290	4,946
Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Securities—trading, Fair Value	0	0
Total assets	0	0
Advances from FHLB at fair value	0	0
Junior subordinated debentures net of unamortized deferred issuance costs at fair value	0	0
Total liabilities	0	0
Recurring [Member] | Level 1 [Member] | U.S. Government and agency [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Securities—trading, Fair Value	0	0
Recurring [Member] | Level 1 [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Securities—trading, Fair Value	0	0
Recurring [Member] | Level 1 [Member] | Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Recurring [Member] | Level 1 [Member] | TPS and TRUP CDOs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading, Fair Value	0	0
Recurring [Member] | Level 1 [Member] | Mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Securities—trading, Fair Value	0	0
Recurring [Member] | Level 1 [Member] | Asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Recurring [Member] | Level 1 [Member] | Equity securities and other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading, Fair Value	0	0
Recurring [Member] | Level 1 [Member] | Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Recurring [Member] | Level 1 [Member] | Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	411,021	470,280
Securities—trading, Fair Value	21,140	27,332
Total assets	438,451	502,558
Advances from FHLB at fair value	32,250	27,250
Junior subordinated debentures net of unamortized deferred issuance costs at fair value	0	0
Total liabilities	38,738	32,239
Recurring [Member] | Level 2 [Member] | U.S. Government and agency [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	29,770	58,660
Securities—trading, Fair Value	1,505	1,481
Recurring [Member] | Level 2 [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	50,028	52,855
Securities—trading, Fair Value	1,440	5,023
Recurring [Member] | Level 2 [Member] | Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	5,018	6,964
Recurring [Member] | Level 2 [Member] | TPS and TRUP CDOs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading, Fair Value	0	0
Recurring [Member] | Level 2 [Member] | Mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	300,810	326,610
Securities—trading, Fair Value	18,136	20,760
Recurring [Member] | Level 2 [Member] | Asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	25,395	25,191
Recurring [Member] | Level 2 [Member] | Equity securities and other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading, Fair Value	59	68
Recurring [Member] | Level 2 [Member] | Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	198	43
Recurring [Member] | Level 2 [Member] | Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	6,290	4,946
Derivative liabilities	6,290	4,946
Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Securities—trading, Fair Value	19,118	35,140
Total assets	19,435	35,270
Advances from FHLB at fair value	0	0
Junior subordinated debentures net of unamortized deferred issuance costs at fair value	78,001	73,928
Total liabilities	78,001	73,928
Recurring [Member] | Level 3 [Member] | U.S. Government and agency [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Securities—trading, Fair Value	0	0
Recurring [Member] | Level 3 [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Securities—trading, Fair Value	0	0
Recurring [Member] | Level 3 [Member] | Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Recurring [Member] | Level 3 [Member] | TPS and TRUP CDOs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading, Fair Value	19,118	35,140
Recurring [Member] | Level 3 [Member] | Mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Securities—trading, Fair Value	0	0
Recurring [Member] | Level 3 [Member] | Asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Recurring [Member] | Level 3 [Member] | Equity securities and other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading, Fair Value	0	0
Recurring [Member] | Level 3 [Member] | Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	317	130
Derivative liabilities	0	0
Recurring [Member] | Level 3 [Member] | Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	$0	$0

FAIR_VALUE_OF_FINANCIAL_INSTRU5

FAIR VALUE OF FINANCIAL INSTRUMENTS (Unobservable Inputs Rollforward) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Borrowings - Junior Subordinated Debentures [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$73,928	$73,063
Liabilities (gains) losses	4,073	865
Purchases, issuances and settlements	0	0
Paydowns and maturities	0	0
Transfers in and/or out of Level 3	0	0
Ending balance	78,001	73,928
TPS and TRUP CDOs [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	35,140	35,741
Assets gains (losses)	5,481	-181
Purchases, issuances and settlements	0	0
Paydowns and maturities	-21,502	-420
Transfers in and/or out of Level 3	0	0
Ending balance	$19,119	$35,140

FAIR_VALUE_OF_FINANCIAL_INSTRU6

FAIR VALUE OF FINANCIAL INSTRUMENTS (Non-recurring Basis) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans individually evaluated for valuation adjustments	$34,446,000	$60,647,000
Impaired loans individually evaluated for valuation adjustments, write-downs	5,344,000	9,998,000
Impaired loans individually evaluated for valuation adjustments, specific reserves	2,966,000	5,188,000
Impaired loans collectively evaluated for valuation adjustments	3,799,374,000	3,357,798,000
Impaired loans collectively evaluated for valuation adjustments, allowances	72,941,000	69,070,000
Mortgage Servicing Rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage servicing rights, valuation adjustments in the period	0	1,300,000	400,000
Servicing Contracts for Third Parties [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans serviced for others	1,391,000,000	1,216,000,000
Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Classifed loans	64,000,000
Impaired classified loans	46,000,000
Impaired loans individually evaluated for valuation adjustments	34,000,000
Impaired loans individually evaluated for valuation adjustments, carrying value	37,000,000
Impaired loans individually evaluated for valuation adjustments, write-downs	3,000,000
Impaired loans individually evaluated for valuation adjustments, specific reserves	3,000,000
Impaired loans collectively evaluated for valuation adjustments	11,000,000
Impaired loans collectively evaluated for valuation adjustments, allowances	126,000
Impairment of real estate owned	$37,000	$785,000

FAIR_VALUE_OF_FINANCIAL_INSTRU7

FAIR VALUE OF FINANCIAL INSTRUMENTS (Assets Measured on Nonrecurring Basis) (Details) (Nonrecurring [Member], USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	$4,725	$10,627
REO	3,352	4,044
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
REO	0	0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
REO	0	0
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	4,725	10,627
REO	3,352	4,044
Net Losses Recognized During the Period
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	-512	-4,890
REO	($453)	($853)

FAIR_VALUE_OF_FINANCIAL_INSTRU8

FAIR VALUE OF FINANCIAL INSTRUMENTS (Fair Value Inputs) (Details) (Level 3 [Member], Income Approach Valuation Technique [Member], USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014
Junior Subordinated Debentures [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Credit spread, variable rate basis	0.31%			0.31%
Credit spread, basis spread on variable rate	5.25%			5.25%
TPS Securities [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Assets gains (losses)	$35	$74	$578
TRUP CDO Securities [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Assets gains (losses)		($255)	$3,300	$4,900
Weighted Average [Member] | Junior Subordinated Debentures [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Discount rate		5.50%		5.26%
Weighted Average [Member] | TPS Securities [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Discount rate		5.50%		5.26%
Weighted Average [Member] | TRUP CDO Securities [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Discount rate		3.85%		3.96%
Weighted Average [Member] | Mortgage Servicing Rights
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Discount rate				11.11%
Fair Value Inputs, Prepayment Rate				19.80%

FAIR_VALUE_OF_FINANCIAL_INSTRU9

FAIR VALUE OF FINANCIAL INSTRUMENTS (Fair Value By Balance Sheet Location) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assets:
Securities—trading, Fair Value	$40,258	$62,472
Securities—available-for-sale	411,021	470,280
Securities—held-to-maturity	137,608	103,610
Liabilities:
Advances from FHLB at fair value	32,250	27,250
Carrying Value
Assets:
Cash and due from banks	126,072	137,349
Securities—trading, Fair Value	40,258	62,472
Securities—available-for-sale	411,021	470,280
Securities—held-to-maturity	131,258	102,513
Loans receivable held for sale	2,786	2,734
Loans receivable	3,831,034	3,415,711
FHLB stock	27,036	35,390
Bank-owned life insurance	63,759	61,945
Mortgage servicing rights	9,030	8,086
Liabilities:
Demand, interest-bearing checking, and money market	2,227,292	1,946,467
Regular savings	901,142	798,764
Certificates of deposit	770,516	872,695
Advances from FHLB at fair value	32,250	27,250
Junior subordinated debentures at fair value	78,001	73,928
Other borrowings	77,185	83,056
Estimated Fair Value
Assets:
Cash and due from banks	126,072	137,349
Securities—trading, Fair Value	40,258	62,472
Securities—available-for-sale	411,021	470,280
Securities—held-to-maturity	137,608	103,610
Loans receivable held for sale	2,807	2,751
Loans receivable	3,722,179	3,297,936
FHLB stock	27,036	35,390
Bank-owned life insurance	63,759	61,945
Mortgage servicing rights	12,987	11,529
Liabilities:
Demand, interest-bearing checking, and money market	1,998,649	1,697,095
Regular savings	784,006	695,863
Certificates of deposit	764,549	867,904
Advances from FHLB at fair value	32,250	27,250
Junior subordinated debentures at fair value	78,001	73,928
Other borrowings	77,185	83,056
Interest Rate Swap [Member] | Carrying Value
Assets:
Derivatives	6,290	4,946
Liabilities:
Derivatives	6,290	4,946
Interest Rate Swap [Member] | Estimated Fair Value
Assets:
Derivatives	6,290	4,946
Liabilities:
Derivatives	6,290	4,946
Interest Rate Contract [Member] | Carrying Value
Assets:
Derivatives	317	130
Liabilities:
Derivatives	198	43
Interest Rate Contract [Member] | Estimated Fair Value
Assets:
Derivatives	317	130
Liabilities:
Derivatives	$198	$43

Recovered_Sheet6

FAIR VALUE OF FINANCIAL INSTRUMENTS (Commitments) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Commitments to sell loans [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance-sheet financial instruments, notional amount	$8,714,000	$9,378,000
Commitments to originate loans [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance-sheet financial instruments, notional amount	20,988,000	15,776,000
Commitment to fund loans [Member] | Level 2 [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance-sheet financial instruments		$0

BANNER_CORPORATION_PARENT_COMP2

BANNER CORPORATION (PARENT COMPANY ONLY) (Statements of Financial Position) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
ASSETS
Other assets	$29,328	$26,799
Total assets	4,723,899	4,388,898
LIABILITIES AND STOCKHOLDERS’ EQUITY
Junior subordinated debentures at fair value	78,001	73,928
Stockholders’ equity	583,624	538,972	506,919	532,450
Total liabilities and stockholders' equity	4,723,899	4,388,898
Banner Corporation
ASSETS
Cash	52,124	45,998
Investment in trust equities	3,716	3,716
Investment in subsidiaries	611,468	575,023
Other assets	8,279	7,280
Total assets	675,587	632,017
LIABILITIES AND STOCKHOLDERS’ EQUITY
Miscellaneous liabilities	2,446	6,157
Deferred tax liability	11,516	12,960
Junior subordinated debentures at fair value	78,001	73,928
Stockholders’ equity	583,624	538,972
Total liabilities and stockholders' equity	$675,587	$632,017

BANNER_CORPORATION_PARENT_COMP3

BANNER CORPORATION (PARENT COMPANY ONLY) (Statements of Operations) (Details) (USD $)	3 Months Ended												12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
INTEREST INCOME:
Interest-bearing deposits	$46,661	$47,064	$43,808	$42,339	$41,607	$41,893	$42,248	$40,968	$41,534	$42,698	$42,290	$41,126	$179,872	$166,716	$167,648
OTHER INCOME (EXPENSE):
Dividend income from subsidiaries													34	18	0
Other income													2,957	3,484	4,697
Other expenses													-13,619	-12,474	-12,795
Income before provision for (benefit from) income taxes	17,344	21,919	25,506	15,616	17,258	17,545	17,414	16,866	19,326	18,027	-6,440	9,184	80,385	69,083	40,097
PROVISION FOR (BENEFIT FROM) INCOME TAXES	5,599	7,076	8,499	5,046	5,704	5,880	5,661	5,284	4,638	2,407	-31,830	0	26,220	22,528	-24,785
NET INCOME	11,745	14,843	17,007	10,570	11,554	11,665	11,753	11,582	14,688	15,620	25,390	9,184	54,165	46,555	64,882
PREFERRED STOCK DIVIDEND AND DISCOUNT ACCRETION
Preferred stock dividend	0	0	0	0	0	0	0	0	611	1,227	1,550	1,550	0	0	4,938
Preferred stock discount accretion	0	0	0	0	0	0	0	0	1,174	1,216	454	454	0	0	3,298
Gain on repurchase of preferred stock	0	0	0	0	0	0	0	0	-401	-2,070	0	0	0	0	-2,471
NET INCOME AVAILABLE TO COMMON SHAREHOLDERS	11,745	14,843	17,007	10,570	11,554	11,665	11,753	11,582	13,304	15,247	23,386	7,180	54,165	46,555	59,117
Banner Corporation
INTEREST INCOME:
Interest-bearing deposits													96	82	218
OTHER INCOME (EXPENSE):
Dividend income from subsidiaries													26,027	24,725	61,329
Equity in undistributed income of subsidiaries													33,707	23,994	23,507
Other income													67	3,016	55
Net change in valuation of financial instruments carried at fair value													-4,073	-865	-23,075
Interest on other borrowings													-2,914	-2,968	-3,395
Other expenses													-2,519	-2,794	-2,375
Income before provision for (benefit from) income taxes													50,391	45,190	56,264
PROVISION FOR (BENEFIT FROM) INCOME TAXES													-3,774	-1,365	-8,618
NET INCOME													54,165	46,555	64,882
PREFERRED STOCK DIVIDEND AND DISCOUNT ACCRETION
Preferred stock dividend													0	0	4,938
Preferred stock discount accretion													0	0	3,298
Gain on repurchase of preferred stock													0	0	-2,471
NET INCOME AVAILABLE TO COMMON SHAREHOLDERS													$54,165	$46,555	$59,117

BANNER_CORPORATION_PARENT_COMP4

BANNER CORPORATION (PARENT COMPANY ONLY) (Statements of Cash Flows) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
OPERATING ACTIVITIES:
Net income	$54,165	$46,555	$64,882
Adjustments to reconcile net income to net cash provided by operating activities:
Increase (decrease) in deferred taxes	2,871	7,528	-35,007
Net change in valuation of financial instruments carried at fair value	-1,374	2,278	16,515
(Increase) decrease in other assets	-2,310	19,426	-818
Increase (decrease) in other liabilities	3,370	4,327	3,569
Net cash provided from operating activities	98,066	95,366	81,415
INVESTING ACTIVITIES:
Net cash provided from (used by) investing activities	-164,067	-206,421	52,479
FINANCING ACTIVITIES
Issuance of stock for stockholder reinvestment program	127	72	36,317
Redemption of preferred stock	0	0	-121,528
Cash dividends paid	-13,462	-7,799	-6,470
Net cash provided from (used by) financing activities	54,724	67,106	-85,032
NET INCREASE (DECREASE) IN CASH AND DUE FROM BANKS	-11,277	-43,949	48,862
CASH AND DUE FROM BANKS, BEGINNING OF YEAR	137,349	181,298	132,436
CASH AND DUE FROM BANKS, END OF YEAR	126,072	137,349	181,298
Banner Corporation
OPERATING ACTIVITIES:
Net income	54,165	46,555	64,882
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed earnings of subsidiaries	-33,707	-23,994	-23,507
Increase (decrease) in deferred taxes	-1,444	17	-13,030
Net change in valuation of financial instruments carried at fair value	4,073	865	23,075
(Increase) decrease in other assets	-3,822	-4,655	-496
Increase (decrease) in other liabilities	222	-1,921	4,940
Net cash provided from operating activities	19,487	16,867	55,864
INVESTING ACTIVITIES:
Funds transferred to deferred compensation trust	-26	-27	-332
Net cash provided from (used by) investing activities	-26	-27	-332
FINANCING ACTIVITIES
Issuance of stock for stockholder reinvestment program	127	72	36,317
Redemption of preferred stock	0	0	-121,528
Cash dividends paid	-13,462	-7,798	-6,470
Net cash provided from (used by) financing activities	-13,335	-7,726	-91,681
NET INCREASE (DECREASE) IN CASH AND DUE FROM BANKS	6,126	9,114	-36,149
CASH AND DUE FROM BANKS, BEGINNING OF YEAR	45,998	36,884	73,033
CASH AND DUE FROM BANKS, END OF YEAR	$52,124	$45,998	$36,884

STOCK_REPURCHASES_Details

STOCK REPURCHASES (Details) (USD $)	3 Months Ended												12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 26, 2014
Stock repurchases
Gain on repurchase of preferred stock	$0	$0	$0	$0	$0	$0	$0	$0	$401	$2,070	$0	$0	$0	$0	$2,471
Common Stock [Member] | Banner Corporation Share Repurchase Plan [Member]
Stock repurchases
Stock Repurchase Program, Number of Shares Authorized to be Repurchased																978,826
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased	978,826												978,826
Stock Repurchased During Period, Shares													0

CALCULATION_OF_EARNINGS_PER_CO2

CALCULATION OF EARNINGS PER COMMON SHARE (Details) (USD $)	3 Months Ended												12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings Per Share [Abstract]
Net income	$11,745	$14,843	$17,007	$10,570	$11,554	$11,665	$11,753	$11,582	$14,688	$15,620	$25,390	$9,184	$54,165	$46,555	$64,882
Preferred stock dividend accrual	0	0	0	0	0	0	0	0	-611	-1,227	-1,550	-1,550	0	0	-4,938
Preferred stock discount accretion	0	0	0	0	0	0	0	0	-1,174	-1,216	-454	-454	0	0	-3,298
Gain on repurchase of preferred stock	0	0	0	0	0	0	0	0	401	2,070	0	0	0	0	2,471
NET INCOME AVAILABLE TO COMMON SHAREHOLDERS	$11,745	$14,843	$17,007	$10,570	$11,554	$11,665	$11,753	$11,582	$13,304	$15,247	$23,386	$7,180	$54,165	$46,555	$59,117
Weighted average number of common shares outstanding
Basic weighted average shares outstanding (in shares)													19,359	19,361	18,650
Diluted weighted shares outstanding (in shares)													19,403	19,397	18,723
Earnings per common share
Basic (in dollars per share)	$0.61	$0.77	$0.88	$0.55	$0.60	$0.60	$0.60	$0.60	$0.69	$0.81	$1.27	$0.40	$2.80	$2.40	$3.17
Diluted (in dollars per share)	$0.60	$0.76	$0.88	$0.54	$0.60	$0.60	$0.60	$0.60	$0.69	$0.80	$1.27	$0.40	$2.79	$2.40	$3.16

CALCULATION_OF_EARNINGS_PER_CO3

CALCULATION OF EARNINGS PER COMMON SHARE (Textuals) (Details)	12 Months Ended
	Dec. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Unvested restricted stock shares included in computation of diluted earnings per share	195,106
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	10,664
Warrant [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	243,998

SELECTED_QUARTERLY_FINANCIAL_D2

SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) (USD $)	3 Months Ended												12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Selected Quarterly Financial Information [Abstract]
Interest income	$49,251	$49,764	$46,540	$45,106	$44,595	$45,037	$45,571	$44,508	$45,525	$47,174	$47,265	$47,198	$190,661	$179,712	$187,162
Interest expense	2,590	2,700	2,732	2,767	2,988	3,144	3,323	3,540	3,991	4,476	4,975	6,072	10,789	12,996	19,514
Net interest income before provision for loan losses	46,661	47,064	43,808	42,339	41,607	41,893	42,248	40,968	41,534	42,698	42,290	41,126	179,872	166,716	167,648
Provision for loan losses	0	0	0	0	0	0	0	0	1,000	3,000	4,000	5,000	0	0	13,000
Net interest income	46,661	47,064	43,808	42,339	41,607	41,893	42,248	40,968	40,534	39,698	38,290	36,126	179,872	166,716	154,648
Other operating income	11,913	13,350	20,133	8,858	12,580	10,142	10,623	9,997	13,311	11,684	-9,064	10,971	54,254	43,342	26,902
Other operating expenses	41,230	38,495	38,435	35,581	36,929	34,490	35,457	34,099	34,519	33,355	35,666	37,913	153,741	140,975	141,453
Income before provision for (benefit from) income taxes	17,344	21,919	25,506	15,616	17,258	17,545	17,414	16,866	19,326	18,027	-6,440	9,184	80,385	69,083	40,097
PROVISION FOR (BENEFIT FROM) INCOME TAXES	5,599	7,076	8,499	5,046	5,704	5,880	5,661	5,284	4,638	2,407	-31,830	0	26,220	22,528	-24,785
NET INCOME	11,745	14,843	17,007	10,570	11,554	11,665	11,753	11,582	14,688	15,620	25,390	9,184	54,165	46,555	64,882
Preferred stock dividend	0	0	0	0	0	0	0	0	611	1,227	1,550	1,550	0	0	4,938
Preferred stock discount accretion	0	0	0	0	0	0	0	0	1,174	1,216	454	454	0	0	3,298
Gain on repurchase and retirement of preferred stock	0	0	0	0	0	0	0	0	-401	-2,070	0	0	0	0	-2,471
NET INCOME AVAILABLE TO COMMON SHAREHOLDERS	$11,745	$14,843	$17,007	$10,570	$11,554	$11,665	$11,753	$11,582	$13,304	$15,247	$23,386	$7,180	$54,165	$46,555	$59,117
Basic earnings (loss) per share (in dollars per share)	$0.61	$0.77	$0.88	$0.55	$0.60	$0.60	$0.60	$0.60	$0.69	$0.81	$1.27	$0.40	$2.80	$2.40	$3.17
Diluted earnings (loss) per share (in dollars per share)	$0.60	$0.76	$0.88	$0.54	$0.60	$0.60	$0.60	$0.60	$0.69	$0.80	$1.27	$0.40	$2.79	$2.40	$3.16
Cumulative dividends declared per common share (in dollars per share)	$0.18	$0.18	$0.18	$0.18	$0.15	$0.15	$0.12	$0.12	$0.01	$0.01	$0.01	$0.01	$0.72	$0.54	$0.04

FINANCIAL_INSTRUMENTS_WITH_OFF2

FINANCIAL INSTRUMENTS WITH OFF-BALANCE-SHEET RISK (Commitments Without Recorded Liability) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Mortgage loan applications, day Interest rate is locked	45 days
Minimum [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Mortgage loan applications, day Interest rate is locked	30 days
Maximum [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Mortgage loan applications, day Interest rate is locked	60 days
Commitments to extend credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract or Notional Amount	1,166,165	$1,073,897
Standby letters of credit and financial guarantees
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract or Notional Amount	9,934	6,990
Commitments to originate loans
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract or Notional Amount	20,988	15,776
Commitments to originate loans held for sale
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract or Notional Amount	29,851	21,434
Commitments to sell loans secured by one- to four-family residential properties
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract or Notional Amount	8,714	9,378
Commitments to sell securities related to mortgage banking activities
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract or Notional Amount	25,000	$15,200

DERIVATIVES_AND_HEDGING_DERIVA2

DERIVATIVES AND HEDGING DERIVATIVES AND HEDGING (Derivatives Designated as Hedging, by Balance Sheet Location) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$6,290,000	$4,946,000
Derivative Liability, Fair Value, Gross Liability	6,290,000	4,946,000
Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	6,290,000	4,946,000
Derivative Liability, Fair Value, Gross Liability	6,290,000	4,946,000
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	7,089,000	7,420,000
Derivative Liability, Notional Amount	7,089,000	7,420,000
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Loans Receivable [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1,165,000	1,295,000
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	$1,165,000	$1,295,000

DERIVATIVES_AND_HEDGING_DERIVA3

DERIVATIVES AND HEDGING DERIVATIVES AND HEDGING (Derivatives Not Designated as Hedging, by Balance Sheet Location) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$6,290,000	$4,946,000
Derivative Liability, Fair Value, Gross Liability	6,290,000	4,946,000
Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	6,290,000	4,946,000
Derivative Liability, Fair Value, Gross Liability	6,290,000	4,946,000
Interest Rate Swap [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	129,000,000
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	163,823,000	171,755,000
Derivative Liability, Notional Amount	167,686,000	142,448,000
Not Designated as Hedging Instrument [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	5,442,000	3,781,000
Not Designated as Hedging Instrument [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	5,323,000	3,694,000
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	134,512,000	135,122,000
Derivative Liability, Notional Amount	134,512,000	135,122,000
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Loans Receivable [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	558,000	791,000
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	5,125,000	3,651,000
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	5,125,000	3,651,000
Not Designated as Hedging Instrument [Member] | Mortgage Loan Commitments [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	29,311,000	14,107,000
Derivative Liability, Notional Amount	0	7,326,000
Not Designated as Hedging Instrument [Member] | Mortgage Loan Commitments [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	317,000	57,000
Not Designated as Hedging Instrument [Member] | Mortgage Loan Commitments [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	0	43,000
Not Designated as Hedging Instrument [Member] | Forward Sales Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	0	22,526,000
Derivative Liability, Notional Amount	33,174,000	0
Not Designated as Hedging Instrument [Member] | Forward Sales Contracts [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	73,000
Not Designated as Hedging Instrument [Member] | Forward Sales Contracts [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	$198,000	$0

DERIVATIVES_AND_HEDGING_DERIVA4

DERIVATIVES AND HEDGING DERIVATIVES AND HEDGING (Gain (Loss) On Derivatives Not Designated in Hedging Relationship) (Details) (Not Designated as Hedging Instrument [Member], USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$33	$136
Mortgage Loan Commitments [Member] | Mortgage Banking Operations [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	221	-174
Forward Sales Contracts [Member] | Mortgage Banking Operations [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	($188)	$310

DERIVATIVES_AND_HEDGING_DERIVA5

DERIVATIVES AND HEDGING DERIVATIVES AND HEDGING (Narrative) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative, Net Liability Position, Aggregate Fair Value	$6.30	$2.70
Collateral Already Posted, Aggregate Fair Value	$11.10	$8.90

DERIVATIVES_AND_HEDGING_DERIVA6

DERIVATIVES AND HEDGING DERIVATIVES AND HEDGING (Derivative Offsetting) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Offsetting Assets and Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	$6,290,000	$4,946,000
Derivative Asset, Fair Value, Gross Liability	0	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	6,290,000	4,946,000
Derivative, Collateral, Obligation to Return Securities	-6,000	-554,000
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	6,284,000	4,392,000
Derivative Liability, Fair Value, Gross Liability	6,290,000	4,946,000
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	6,290,000	4,946,000
Derivative, Collateral, Right to Reclaim Securities	-6,000	-554,000
Derivative, Collateral, Right to Reclaim Cash	-6,279,000	-2,657,000
Derivative Liability, Fair Value, Amount Offset Against Collateral	5,000	1,735,000
Interest Rate Swap [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	6,290,000	4,946,000
Derivative Asset, Fair Value, Gross Liability	0	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	6,290,000	4,946,000
Derivative, Collateral, Obligation to Return Securities	-6,000	-554,000
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	6,284,000	4,392,000
Derivative Liability, Fair Value, Gross Liability	6,290,000	4,946,000
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	6,290,000	4,946,000
Derivative, Collateral, Right to Reclaim Securities	-6,000	-554,000
Derivative, Collateral, Right to Reclaim Cash	-6,279,000	-2,657,000
Derivative Liability, Fair Value, Amount Offset Against Collateral	$5,000	$1,735,000