Banner (BANR) 10-K 29 Feb 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Jan. 31, 2016	Jun. 30, 2015
Document Information [Line Items]
Entity Registrant Name	Banner Corporation
Document Type	10-K
Document Period End Date	Dec. 31, 2015
Amendment Flag	false
Entity Central Index Key	946,673
Current Fiscal Year End Date	--12-31
Entity Public Float			$ 979,733,679
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	2,015
Document Fiscal Period Focus	FY
Voting Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		32,817,789
Nonvoting Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		1,424,466

CONSOLIDATED STATEMENTS OF FINA

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
ASSETS
Cash and due from banks	$ 117,657	$ 71,077
Interest-bearing Deposits in Banks and Other Financial Institutions	144,260	54,995
Cash and Cash Equivalents, at Carrying Value	261,917	126,072
Securities—trading, amortized cost $39,344 and $47,480, respectively	34,134	40,258
Securities—available-for-sale, amortized cost $1,139,740 and $411,424, respectively	1,138,573	411,021
Securities—held-to-maturity, fair value $226,627 and $137,608, respectively	220,666	131,258
Federal Home Loan Bank (FHLB) stock	16,057	27,036
Held for sale	44,712	2,786
Loans receivable	7,314,504	3,831,034
Allowance for loan losses	(78,008)	(75,907)
Total loans, net	7,236,496	3,755,127
Accrued interest receivable	29,627	15,279
Real estate owned (REO), held for sale, net	11,627	3,352
Property and equipment, net	167,604	91,185
Goodwill	247,738	0
Other intangible assets, net	36,762	2,831
Bank-owned life insurance (BOLI)	156,865	63,759
Deferred tax assets, net	134,970	23,871
Income tax receivable, net	1,607	0
Other assets	56,943	29,328
Total assets	9,796,298	4,723,163
Deposits:
Non-interest-bearing	2,619,618	1,298,866
Interest-bearing transaction and savings accounts	4,081,580	1,829,568
Interest-bearing certificates	1,353,870	770,516
Total deposits	8,055,068	3,898,950
Advances from FHLB at fair value	133,381	32,250
Other borrowings	98,325	77,185
Junior subordinated debentures at fair value (issued in connection with Trust Preferred Securities)	92,480	78,001
Accrued expenses and other liabilities	76,511	37,082
Deferred compensation	40,474	16,807
Total liabilities	$ 8,496,239	$ 4,140,275
COMMITMENTS AND CONTINGENCIES (Note 23)
SHAREHOLDERS’ EQUITY
Preferred stock - $0.01 par value per share, 500,000 shares authorized; no shares issued and outstanding at December 31, 2015 and December 31, 2014	$ 0	$ 0
Retained earnings	39,615	14,264
Accumulated other comprehensive loss	(730)	(258)
Carrying value of shares held in trust for stock related compensation plans	(6,928)	(6,669)
Liability for common stock issued to deferred, stock related, compensation plans	6,928	6,669
Shareholders’ equity	1,300,059	582,888
Total liabilities and stockholders' equity	9,796,298	4,723,163
Voting Common Stock [Member]
SHAREHOLDERS’ EQUITY
Common stock and paid in capital	1,193,270	568,882
Nonvoting Common Stock [Member]
SHAREHOLDERS’ EQUITY
Common stock and paid in capital	$ 67,904	$ 0

CONSOLIDATED STATEMENTS OF FIN3

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
ASSETS
Securities—trading, amortized cost basis	$ 39,344	$ 47,480
Securities—available-for-sale, amortized cost basis	1,139,740	411,424
Held-to-maturity Securities, Fair Value	$ 226,627	$ 137,608
SHAREHOLDERS’ 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, shares held in employee trust (ESOP)	0	0
Voting Common Stock [Member]
SHAREHOLDERS’ EQUITY
Common stock, share par value	$ 0.01	$ 0.01
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	32,817,789	19,571,548
Common stock, shares outstanding	32,817,789	19,571,548
Nonvoting Common Stock [Member]
SHAREHOLDERS’ EQUITY
Common stock, share par value	$ 0.01	$ 0
Common stock, shares authorized	5,000,000	0
Common stock, shares issued	1,424,466	0
Common stock, shares outstanding	1,424,466	0

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
INTEREST INCOME:
Loans receivable	$ 237,292	$ 177,541	$ 167,204
Mortgage-backed securities	9,049	5,779	5,168
Securities and cash equivalents	8,092	7,341	7,340
Total interest income	254,433	190,661	179,712
INTEREST EXPENSE:
Deposits	8,385	7,578	9,737
FHLB advances	311	125	99
Other borrowings	211	172	192
Junior subordinated debentures	3,247	2,914	2,968
Total interest expense	12,154	10,789	12,996
Net interest income before provision for loan losses	242,279	179,872	166,716
PROVISION FOR LOAN LOSSES	0	0	0
Net interest income	242,279	179,872	166,716
NON-INTEREST INCOME
Deposit fees and other service charges	40,607	30,553	26,581
Mortgage banking operations	17,720	10,249	11,170
Bank Owned Life Insurance Income	2,497	1,809	2,020
Miscellaneous	2,821	1,885	2,784
Other operating income	63,645	44,496	42,555
Net gain (loss) on sale of securities	(540)	42	1,022
Other-than-temporary impairment recovery	0	0	409
Net change in valuation of financial instruments carried at fair value	(813)	1,374	(2,278)
Acquisition termination fee	0	0	2,954
Acquisition bargain purchase gain	0	9,079	0
Total non-interest income	62,292	54,991	44,662
NON-INTEREST EXPENSE:
Salary and employee benefits	127,282	89,778	84,388
Less capitalized loan origination costs	(14,379)	(11,730)	(11,227)
Occupancy and equipment	30,366	22,743	21,423
Information/computer data services	12,110	8,131	7,309
Payment and card processing expenses	16,430	11,460	9,870
Professional services	4,828	3,753	3,781
Advertising and marketing	7,649	6,266	6,885
Deposit insurance	3,189	2,415	2,329
State/municipal business and use taxes	1,889	1,437	1,941
REO operations	397	(446)	(689)
Amortization of core deposit intangibles	3,164	1,990	1,941
Miscellaneous	17,565	13,619	12,474
Total other operating expense, before acquisition related costs	210,490	149,416	140,425
Acquisition related costs	26,110	4,325	550
Total non-interest expense	236,600	153,741	140,975
Income before provision for income taxes	67,971	81,122	70,403
PROVISION FOR INCOME TAXES	22,749	27,052	24,189
NET INCOME	$ 45,222	$ 54,070	$ 46,214
Earnings per common share
Basic (in dollars per share)	$ 1.90	$ 2.79	$ 2.39
Diluted (in dollars per share)	1.89	2.79	2.38
Cumulative dividends declared per common share (in dollars per share)	$ 0.72	$ 0.72	$ 0.54
Basic weighted average shares outstanding (in shares)	23,801,373	19,359,409	19,361,411
Weighted Average Number of Shares Outstanding, Diluted	23,866,621	19,402,656	19,397,360

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
NET INCOME	$ 45,222	$ 54,070	$ 46,214
OTHER COMPREHENSIVE INCOME (LOSS), NET OF INCOME TAXES:
Unrealized holding (loss) gain on securities—available-for-sale arising during the period	(645)	4,319	(8,066)
Income tax benefit (expense) related to securities—available-for-sale unrealized holding gains (losses)	249	(1,555)	2,896
Reclassification for net (gains) losses on securities—available-for-sale realized in earnings	(119)	(41)	116
Income tax benefit (expense) related to securities—available-for-sale realized (gains) losses	43	15	(42)
Other comprehensive income (loss)	(472)	2,738	(5,096)
COMPREHENSIVE INCOME	$ 44,750	$ 56,808	$ 41,118

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common 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]
Balance, beginning of the period at Dec. 31, 2012	$ 506,619		$ 567,907	$ (61,402)	$ 2,101	$ (1,987)
Balance, beginning of the period, shares at Dec. 31, 2012		19,454,965
Net income	46,214			46,214
Other comprehensive income (loss)	(5,097)				(5,097)
Accrual of dividends on common stock	(10,526)			(10,526)
Proceeds from issuance of common stock for stockholder reinvestment program, net of registration expenses amount	72		72
Proceeds from issuance of common stock for stockholder reinvestment program shares		2,098
Amortization of share-based compensation related to restricted stock grants, net of shares surrendered	1,049		1,049
Issuance of unvested restricted common stock, net, shares		86,706
Balance, end of the period, shares at Dec. 31, 2013		19,543,769
Balance, end of the period at Dec. 31, 2013	538,331		569,028	(25,714)	(2,996)	(1,987)
Net income	54,070			54,070
Other comprehensive income (loss)	2,738				2,738
Accrual of dividends on common stock	(14,092)			(14,092)
Redemption of unallocated shares upon termination of ESOP	0		(1,987)			1,987
Redemption of unallocated shares upon termination of ESOP, shares		(34,340)
Repurchase of shares upon termination of ESOP	(555)		(555)
Repurchase of shares upon termination of ESOP, shares		(13,550)
Proceeds from issuance of common stock for stockholder reinvestment program, net of registration expenses amount	127		127
Proceeds from issuance of common stock for stockholder reinvestment program shares		3,170
Amortization of share-based compensation related to restricted stock grants, net of shares surrendered	2,203		2,203
Issuance of unvested restricted common stock, net, shares		72,499
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	66
Balance, end of the period, shares at Dec. 31, 2014		19,571,548
Balance, end of the period at Dec. 31, 2014	582,888		568,882	14,264	(258)	0
Net income	45,222			45,222
Other comprehensive income (loss)	(472)				(472)
Accrual of dividends on common stock	(19,871)			(19,871)
Proceeds from issuance of common stock for stockholder reinvestment program, net of registration expenses amount	34		34
Proceeds from issuance of common stock for stockholder reinvestment program shares		810
Amortization of share-based compensation related to restricted stock grants, net of shares surrendered	3,088		3,088
Issuance of unvested restricted common stock, net, shares		120,043
Stock Issued During Period, Value, Acquisitions	688,773
Stock Issued During Period, Shares, Acquisitions		14,549,854
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	397
Balance, end of the period, shares at Dec. 31, 2015		34,242,255
Balance, end of the period at Dec. 31, 2015	$ 1,300,059		$ 1,261,174	$ 39,615	$ (730)	$ 0

CONSOLIDATED STATEMENTS OF CHA7

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Parenthetical) - $ / shares	3 Months Ended												12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	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, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Stockholders' Equity [Abstract]
Accrual of dividends on common share (dollars per share)	$ 0.18	$ 0.18	$ 0.18	$ 0.18	$ 0.18	$ 0.18	$ 0.18	$ 0.18	$ 0.15	$ 0.15	$ 0.12	$ 0.12	$ 0.72	$ 0.72	$ 0.54

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
OPERATING ACTIVITIES:
Net income	$ 45,222	$ 54,070	$ 46,214
Adjustments to reconcile net income to net cash provided from operating activities:
Depreciation	9,957	8,064	7,457
Deferred income and expense, net of amortization	(1,534)	1,541	3,200
Amortization of core deposit intangibles	3,164	1,990	1,941
Loss (gain) on sale of securities, net	540	(42)	(1,022)
Other-than-temporary impairment recovery	0	0	(409)
Net change in valuation of financial instruments carried at fair value	813	(1,374)	2,278
Purchases of securities—trading	(6,338)	(2,387)	(32,413)
Proceeds from sales of securities—trading	4,419	2,387	34,308
Principal repayments and maturities of securities—trading	9,535	27,709	6,509
Bargain purchase gain on acquisition	0	(9,079)	0
(Increase) decrease in deferred taxes	(3,906)	2,966	7,869
(Decrease) increase in current taxes payable	(1,519)	11,771	(10,818)
Equity-based compensation	3,486	2,269	1,049
Increase in cash surrender value of BOLI	(2,481)	(1,788)	(1,999)
Gain on sale of loans, net of capitalized servicing rights	(10,716)	(6,080)	(6,498)
Gain on disposal of real estate held for sale and property and equipment	(391)	(1,076)	(2,521)
Provision for real estate held for sale	216	36	785
Origination of loans held for sale	(709,035)	(361,859)	(427,542)
Proceeds from sales of loans held for sale	677,166	367,888	443,225
Net change in:
Other assets	(7,319)	(2,310)	19,426
Other liabilities	4,090	3,370	4,327
Net cash provided from operating activities	15,369	98,066	95,366
INVESTING ACTIVITIES:
Purchases of securities—available-for-sale	(141,989)	(58,705)	(197,911)
Principal repayments and maturities of securities—available-for-sale	113,431	62,520	84,424
Proceeds from sales of securities—available-for-sale	232,620	56,267	103,274
Purchases of securities—held-to-maturity	(13,357)	(38,961)	(26,221)
Principal repayments and maturities of securities—held-to-maturity	12,978	9,194	9,788
Loan originations, net	(32,675)	(144,152)	(167,085)
Purchases of loans and participating interest in loans	(323,533)	(194,381)	(48,725)
Proceeds from sales of other loans	124,407	11,277	19,305
Net cash received from acquisitions, net of branch divestitures	24,208	127,557	6,809
Purchases of property and equipment, net of sales	(12,072)	(5,935)	(8,211)
Proceeds from sale of real estate held for sale, net	4,740	4,923	16,944
Proceeds from FHLB stock repurchase program	48,843	8,354	1,315
Purchase of FHLB stock	(23,634)	0	0
Other	1,092	(2,025)	(127)
Net cash used by investing activities	15,059	(164,067)	(206,421)
FINANCING ACTIVITIES
Increase in deposits, net	226,821	68,938	51,417
Proceeds from Federal Home Loan Bank Advances	859,400	1,483,300	1,020,705
Payments for Federal Home Loan Bank Advances	(979,808)	(1,478,308)	(1,003,712)
Increase (decrease) in other borrowings, net	16,140	(5,871)	6,423
Cash dividends paid	(17,170)	(13,462)	(7,799)
Cash proceeds from issuance of shares for shareholder reinvestment plan	34	127	72
Net cash provided from financing activities	105,417	54,724	67,106
NET CHANGE IN CASH AND CASH EQUIVALENTS	135,845	(11,277)	(43,949)
CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR	126,072	137,349	181,298
CASH AND CASH EQUIVALENTS, END OF YEAR	261,917	126,072	137,349
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Interest paid in cash	12,252	10,929	13,362
Taxes paid in cash	27,256	13,047	22,828
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	4,456	3,493	3,448
ACQUISITIONS (Note 3):
Assets acquired	4,827,237	221,206	8,710
Liabilities assumed	$ 4,250,395	$ 212,127	$ 8,710

BASIS OF PRESENTATION AND SUMMA

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2015
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 headquarters in Walla Walla, Washington and, as of December 31, 2015 , its 199 branch offices and nine loan production offices located in Washington, Oregon, California, Utah 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 of Des Moines (FHLB) advances, other borrowings and junior subordinated debentures. Net income also is affected by the level of the Company’s non-interest income, including deposit fees and other service charges, gains and losses on the sale of securities, results of mortgage banking operations, which includes loan origination and servicing fees and gains and losses on the sale of loans, as well as non-interest expense, 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. Basis of Presentation and 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. The consolidated financial statements of the Company have been prepared in accordance with generally accepted accounting principles in the United States (GAAP) and under the rules and regulations of the U.S. Securities and Exchange Commission (the SEC). Subsequent Events: The Company has evaluated events and transactions subsequent to December 31, 2015 for potential recognition or disclosure . Cash and Cash Equivalents: Cash and cash equivalents include cash and due from banks and temporary investments which are federal funds sold and interest bearing balances due from other banks. Cash and cash equivalents generally have maturities of three months or less at the date of purchase. Business Combinations: Business combinations are accounted for using the acquisition method of accounting and, accordingly, assets acquired and liabilities assumed, both tangible and intangible, and consideration exchanged are recorded at acquisition date fair values. The excess purchase consideration over fair value of net assets acquired is recorded as goodwill. In the event that the fair value of net assets acquired exceeds the purchase price, including fair value of liabilities assumed, a bargain purchase gain is recorded on that acquisition. Expenses incurred in connection with a business combination are expensed as incurred. Changes in deferred tax asset valuation allowances related to acquired tax uncertainties are recognized in net income after the measurement period. Use of Estimates: In the opinion of management, the accompanying consolidated statements of financial condition and related consolidated statements of operations, comprehensive income, changes in shareholders’ equity and cash flows reflect all adjustments (which include reclassification and normal recurring adjustments) that are necessary for a fair presentation in conformity with 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 (vii) the valuation of assets and liabilities acquired in business combinations. These policies and judgments, estimates and assumptions are described in greater detail in subsequent Notes to the Consolidated Financial Statements. 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 shareholders’ 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 18 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, 2015 , the Banks had $16.1 million in FHLB stock, compared to $27.0 million at December 31, 2014 . 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 Company has determined there is not any impairment on the FHLB stock investment as of December 31, 2015 . Loans Receivable: The Banks originate residential one- to four-family and multifamily mortgage loans for both portfolio investment and sale in the secondary market. The Banks also originate construction and land development, commercial 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 appropriately reported as TDRs when the Banks grant 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. Loans Held for Sale . Residential one- to four-family and multifamily mortgage loans with the intent to be sold in the secondary market are considered held for sale. These loans are carried at the lower of aggregate cost or estimated market value. Fair values for residential mortgage loans held for sale are determined by comparing actual loan rates to current secondary market prices for similar loans. Fair values for multifamily loans held for sale are calculated using recent sales data for comparable loans. Net unrealized losses on loans held for sale are recognized through a valuation allowance by charges to income. Non-refundable fees and direct loan origination costs related to loans held for sale are recognized as part of the cost basis of the loan at the time of sale. Gains and losses on sales of loans held for sale are determined using the specific identification method and are recorded in the mortgage banking operations component of non-interest income . Acquired Loans: Purchased loans, including loans acquired in business combinations, are recorded at their fair value at the acquisition date. Credit discounts are included in the determination of fair value; therefore, an allowance for loan and lease losses is not recorded at the acquisition date. Acquired loans are evaluated upon acquisition and classified as either purchased credit-impaired or purchased non-credit-impaired. Purchased credit-impaired (PCI) loans reflect credit deterioration since origination such that it is probable at acquisition that the Company will be unable to collect all contractually required payments. The excess of the cash flows expected to be collected over a PCI pool's carrying value is considered to be the accretable yield and is recognized as interest income over the estimated life of the pool using the effective yield method. The excess of the undiscounted contractual balances due over the cash flows expected to be collected is considered to be the nonaccretable difference. The nonaccretable difference represents our estimate of the credit losses expected to occur and was considered in determining the fair value of the loans as of the acquisition date. Subsequent to the acquisition date, any increases in expected cash flows over those expected at purchase date in excess of fair value are adjusted through a change to the accretable yield on a prospective basis. Any subsequent decreases in expected cash flows attributable to credit deterioration are recognized by recording a provision for loan losses. For purchased non-credit-impaired loans, the difference between the fair value and unpaid principal balance of the loan at the acquisition date is amortized or accreted to interest income over the life of the loans. Any subsequent deterioration in credit quality is recognized by recording a provision for loan losses. Income Recognition on Nonaccrual and Impaired Loans and Securities: 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 or principal 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 GAAP. 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 loan losses 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 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 for loan losses. 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 for loan losses 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 if the loan is collateral dependent, at the fair value of collateral less selling costs. 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 for loan losses 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 loan 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 for loan losses 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. Reserve for Unfunded Commitments: A reserve for unfunded commitments is maintained at a level that, in the opinion of management, is adequate to absorb probable losses associated with the Banks' commitments to lend funds under existing agreements such as letters or lines of credit. Management determines the adequacy of the reserve for unfunded commitments based upon reviews of individual credit facilities, current economic conditions, the risk characteristics of the various categories of commitments and other relevant factors. The reserve is based on estimates and ultimate losses may vary from the current estimates. These estimates are evaluated on a regular basis and, as adjustments become necessary, they are reported in earnings in the periods in which they become known. Draws on unfunded commitments that are considered uncollectible at the time funds are advanced are charged to the allowance for loan losses. Provisions for unfunded commitment losses are added to the reserve for unfunded commitments, which is included in other liabilities. Real Estate Held for Sale: Property acquired by foreclosure or deed in lieu of foreclosure is initially recorded at the estimated fair value of the property, less expected selling costs. 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 is carried at cost less accumulated depreciation. The provision for depreciation is based upon the straight-line method applied to individual assets and groups of assets acquired in the same year over the lesser of their estimated useful lives or the related lease terms of the assets: 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. Goodwill: Goodwill represents the excess of the purchase consideration over the fair value of the assets acquired, net of the fair values of liabilities assumed in a business combination and is not amortized but is reviewed annually, or more frequently as current circumstances and conditions warrant, for impairment. An assessment of qualitative factors is completed to determine if it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If the qualitative analysis concludes that further analysis is required, then a quantitative impairment test would be completed. The quantitative goodwill impairment test is a two-step process. The first step compares the reporting unit's estimated fair values, including goodwill, to its carrying amount. If the carrying amount exceeds its fair value, then goodwill impairment may be indicated. The second step allocates the reporting units fair value to its assets and liabilities. If the unallocated fair value does not exceed the carrying amount of goodwill then an impairment loss would be recognized as a charge to earnings. 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 ten 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 values are estimated based on an independent dealer analysis of discounted cash flows. 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 Statements 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. 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.” Banner Bank is a party to $12.0 million in notional amounts of interest rate swaps at December 31, 2015 . 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, Banner Bank uses an interest rate swap program for commercial loan customers that provides the client with a variable rate loan and enters into an interest rate swap 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. At December 31, 2015 , Banner Bank had $282.0 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 are reflected in other assets or other liabilities as appropriate. 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 i

ACCOUNTING STANDARDS RECENTLY A

ACCOUNTING STANDARDS RECENTLY ADOPTED OR ISSUED	12 Months Ended
	Dec. 31, 2015
Accounting Changes and Error Corrections [Abstract]
ACCOUNTING STANDARDS RECENTLY ADOPTED OR ISSUED	ACCOUNTING STANDARDS RECENTLY ISSUED OR ADOPTED Investing in Qualified Affordable Housing Projects In January 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (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 are applied retrospectively to all periods presented. ASU No. 2014-01 was effective beginning after December 15, 2014 and was adopted by the Company, as of January 1, 2015. The new standard has been retrospectively applied resulting in changes to other non-interest income, tax expense and net income, deferred tax asset, other assets and retained earnings in the prior periods presented. The effect of this change on the revised annual Consolidated Statements of Operations was a decrease in net income of $95,000 and $341,000 for the years ended December 31, 2014 and 2013, respectively. All prior periods have been reclassified to conform to the current presentation. 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 was adopted by the Company, as of January 1, 2015. At December 31, 2015 , the Company had $3.4 million of foreclosed residential real estate properties held as other real estate owned. The recorded investment in one- to four-family residential loans in the process of foreclosure was $2.8 million at both December 31, 2015 . 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. Under the terms of ASU 2015-14 the standard is effective for interim and annual periods beginning after December 15, 2017. Early application is permitted only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period. 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. Customer's Accounting for Fees Paid in a Cloud Computing Arrangement In April 2015, FASB issued ASU No. 2015-05, Customer's Accounting for Fees Paid in a Cloud Computing Arrangement . The amendments in this ASU provide guidance to customers in cloud computing arrangements about whether a cloud computing arrangement includes a software license. If a cloud computing arrangement includes a software license, the customer should account for the software license element of the arrangement consistent with the acquisition of other software licenses. If a cloud computing arrangement does not include a software license, the customer should account for the arrangement as a service contract. The amendments are effective for annual periods, including interim periods within those annual periods, beginning after December 15, 2015. Early adoption is permitted. This ASU is not expected to have a material effect on the Company's Consolidated Financial Statements. Push-down Accounting—Amendments to SEC Paragraphs Pursuant to Staff Accounting Bulletin No. 115 In May 2015, FASB issued ASU No. 2015-08, Push-down Accounting—Amendments to SEC Paragraphs Pursuant to Staff Accounting Bulletin No. 115 (SEC Update) . The amendments in the SEC Update conform the accounting guidance with the various SEC paragraphs pursuant to the SEC Staff Accounting Bulletin No. 115. These amendments are effective immediately. This ASU does not have a material effect on the Company's Consolidated Financial Statements. Business Combinations—Simplifying the Accounting for Measurement-Period Adjustments In September 2015, FASB issued ASU No. 2015-16, Simplifying the Accounting for Measurement-Period Adjustments . The amendments in this ASU require that an acquirer recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period when the adjustment amounts are determined. The acquirer is required to record in the same period's financial statements the effect on earnings from changes in depreciation, amortization, or other income effects resulting from the change to provisional amounts, calculated as if the accounting had been completed at the acquisition date. The acquirer must present separately on the income statement, or disclose in the notes, the amount recorded in current-period earnings that would have been recorded in previous reporting periods if the provisional amount had been recognized at the acquisition date. The amendments in this ASU are effective for fiscal years beginning after December 15, 2015, including interim periods within those fiscal years. This ASU may have a material effect on the Company's Consolidated Financial Statements depending on the significance of future adjustments to provisional amounts, if any. Recognition and Measurement of Financial Assets and Financial Liabilities In January 2016, FASB issued ASU No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities . The amendments in this ASU require equity securities to be measured at fair value with changes in the fair value recognized through net income. The amendments allow equity investments that do not have readily determinable fair values to be remeasured at fair value under certain circumstances and require enhanced disclosures about those investments. The amendments simplify the impairment assessment of equity investments without readily determinable fair values. The amendments also eliminate the requirement to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet. The amendments in this ASU require separate presentation in other comprehensive income of the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. This amendment excludes from net income gains or losses that the entity may not realize because those financial liabilities are not usually transferred or settled at their fair values before maturity. The amendments in this ASU require separate presentation of financial assets and financial liabilities by measurement category and form of financial asset (that is, securities or loans and receivables) on the balance sheet or in the accompanying notes to the financial statements. The amendments in this ASU are effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The Company is currently evaluating the provisions of ASU No. 2016-01 to determine the potential impact the new standard will have on the Company's Consolidated Financial Statements. Leases (Topic 842) In February 2016, FASB issued ASU No. 2016-02, Leases (Topic 842) . The amendments in this ASU require lessees to recognize the following for all leases (with the exception of short-term) at the commencement date; a lease liability, which is a lessee‘s obligation to make lease payments arising from a lease, measured on a discounted basis; and a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. The amendments in this ASU leave lessor accounting largely unchanged, although certain targeted improvements were made to align lessor accounting with the lessee accounting model. This ASU simplifies the accounting for sale and leaseback transactions primarily because lessees must recognize lease assets and lease liabilities. Lessees will no longer be provided with a source of off-balance sheet financing. The amendments in this ASU are effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early application is permitted upon issuance. Lessees (for capital and operating leases) and lessors (for sales-type, direct financing, and operating leases) must apply a modified retrospective transition approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. The modified retrospective approach would not require any transition accounting for leases that expired before the earliest comparative period presented. Lessees and lessors may not apply a full retrospective transition approach. The Company is currently evaluating the provisions of ASU No. 2016-02 to determine the potential impact the new standard will have on the Company's Consolidated Financial Statements.

BUSINESS COMBINATIONS BUSINESS

BUSINESS COMBINATIONS BUSINESS COMBINATIONS	12 Months Ended
	Dec. 31, 2015
Business Combinations [Abstract]
BUSINESS COMBINATIONS	BUSINESS COMBINATIONS Acquisition of Starbuck Bancshares, Inc. Effective as of the close of business on October 1, 2015 , the Company acquired Starbuck Bancshares, Inc. (Starbuck) and its subsidiary, AmericanWest Bank (AmericanWest), a Washington state chartered commercial bank headquartered in Spokane, Washington with 98 branches serving markets in Washington, Oregon, Idaho, California and Utah. On that date, Starbuck merged with and into Banner and AmericanWest merged with and into Banner Bank. The merged banks are operating as Banner Bank. Pursuant to the previously announced terms of the merger, the equity holders of Starbuck received an aggregate of $130.0 million in cash and 13.23 million shares of Banner voting common stock and nonvoting common stock. The acquisition provided $4.46 billion in assets, $3.64 billion in deposits and $3.00 billion in loans to Banner. At the closing date, the combined company had approximately $9.9 billion in assets and 203 branches. The application of the acquisition method of accounting resulted in recognition of a CDI asset of $33.5 million and goodwill of $226.0 million . The acquired CDI has been determined to have a useful life of approximately ten years and will be amortized on an accelerated basis. Goodwill is not amortized but will be evaluated for impairment on an annual basis or more often if circumstances dictate to determine if the carrying value remains appropriate. Goodwill will not be deductible for income tax purposes as the acquisition is accounted for as a tax-free exchange for tax purposes. The following table presents a summary of the consideration paid and the estimated fair values as of the acquisition date for each major class of assets acquired and liabilities assumed (in thousands): Starbuck October 1, 2015 Consideration to Starbuck equityholders: Cash paid $ 130,000 Fair value of common shares issued 630,674 Total consideration 760,674 Fair value of assets acquired: Cash and cash equivalents $ 95,821 Securities 1,037,238 Loans receivable (contractual amount of $3.04 billion) 2,997,640 REO, held for sale 5,706 Property and equipment 66,549 CDI 33,500 Deferred tax asset 107,847 Other assets 113,173 Total assets acquired 4,457,474 Fair value of liabilities assumed: Deposits 3,638,596 FHLB advances 221,442 Junior subordinated debentures 5,806 Other liabilities 57,003 Total liabilities assumed 3,922,847 Net assets acquired 534,627 Goodwill $ 226,047 Acquired goodwill represents the premium the Company paid over the fair value of the net tangible and intangible assets acquired. The acquisition complements the Company's growth strategy, including expanding our geographic footprint in markets throughout the Northwest, Utah and California. The Company paid this premium for a number of reasons, including growing the Company's customer base, acquiring assembled workforces, and expanding its presence in new markets. See Note 17, Goodwill, Other Intangible Assets and Mortgage Servicing Rights for the accounting for goodwill and other intangible assets. Amounts recorded are preliminary estimates of fair value. Additional adjustments to the acquisition accounting may be required and would most likely involve loans, or property and equipment, or the deferred tax asset. As of October 1, 2015, the unpaid principal balance on purchased non-credit-impaired loans was $2.95 billion . The fair value of the purchased non-credit-impaired loans was $2.94 billion , resulting in a discount of $17.7 million recorded on these loans. The principal cash flows not expected to be collected on these loans was estimated to be $44.1 million . This discount is being accreted into income over the life of the loans on an effective yield basis. The following table presents the acquired PCI loans as of the acquisition date (in thousands): Starbuck October 1, 2015 Acquired PCI loans: Contractually required principal and interest payments $ 98,746 Nonaccretable difference (26,162 ) Cash flows expected to be collected 72,584 Accretable yield (11,071 ) Fair value of PCI loans $ 61,513 The following table presents certain unaudited pro forma information for illustrative purposes only, for the years ended December 31, 2015 and 2014 as if Starbuck had been acquired on January 1, 2014 . This unaudited estimated pro forma financial information combines the historical results of Starbuck with the Company’s consolidated historical results. Pro forma adjustments include accretion of loan discount, accretion of investment premiums, amortization of deposit premium, amortization of CDI, reversal of acquisition expense, and reversal of historical recorded amounts for similar items, with all adjustments tax effected. The pro forma information is not indicative of what would have occurred had the acquisition actually occurred on January 1, 2014 . In particular, no adjustments have been made to eliminate the impact of other-than-temporary impairment losses and losses recognized on the sale of securities that may not have been necessary had the investment securities been recorded at fair value as of January 1, 2014 . The unaudited pro forma information does not consider any changes to the provision for credit losses resulting from recording loan assets at fair value. Additionally, Banner expects to achieve further operating cost savings and other business synergies, including revenue growth, as a result of the acquisition which are not reflected in the pro forma amounts that follow. As a result, actual amounts would have differed from the unaudited pro forma information presented (in thousands except per share amounts): Pro Forma Years Ended December 31 2015 2014 Total revenues (net interest income plus non-interest income) $ 455,427 $ 430,984 Net income $ 86,255 $ 87,031 Earnings per share - basic $ 2.56 $ 2.67 Earnings per share - diluted $ 2.55 $ 2.67 The operating results of the Company include the operating results produced by the acquired assets and assumed liabilities of Starbuck for the period October 2, 2015 to December 31, 2015 . Disclosure of the amount of Starbuck's revenue and net income (excluding integration costs) included in the Company’s Consolidated Statements of Operations is impracticable due to the integration of the operations, systems and accounting for this acquisition occurring in different stages. 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. Siuslaw merged with and into the Company and, immediately thereafter, 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. The acquisition provided $369.8 million in assets, $316.4 million in deposits and $247.1 million in loans. The application of the acquisition method of accounting resulted in recognition of a CDI asset of $3.9 million and goodwill of $21.7 million . The acquired CDI has been determined to have a useful life of approximately eight years and will be amortized on an accelerated basis. Goodwill is not amortized but will be evaluated for impairment on an annual basis or more often if circumstances dictate to determine if the carrying value remains appropriate. The goodwill is not deductible for income tax purposes since the acquisition is accounted for as a tax-free exchange for tax purposes. The following table presents a summary of the consideration paid and the estimated fair values as of the acquisition date for each major class of assets acquired and liabilities assumed (in thousands): Siuslaw March 6, 2015 Consideration to Siuslaw shareholders: Cash paid $ 5,806 Fair value of common shares issued 58,100 Total consideration 63,906 Fair value of assets acquired: Cash and cash equivalents $ 84,405 Securities—available-for-sale 12,865 Loans receivable (contractual amount of $252.2 million) 247,098 REO, held for sale 2,525 Property and equipment 8,127 CDI 3,895 Other assets 10,848 Total assets acquired 369,763 Fair value of liabilities assumed: Deposits 316,406 Junior subordinated debentures 5,959 Other liabilities 5,183 Total liabilities assumed 327,548 Net assets acquired $ 42,215 Goodwill 21,691 Acquired goodwill represents the premium the Company paid over the fair value of the net tangible and intangible assets acquired. The acquisition complements the Company's growth strategy, including expanding our geographic footprint in markets throughout the Northwest. The Company paid this premium for a number of reasons, including growing the Company's customer base, acquiring assembled workforces, and expanding its presence in new markets. See Note 17, Goodwill, Other Intangible Assets and Mortgage Servicing Rights for the accounting for goodwill and other intangible assets. Amounts recorded are estimates of fair value. Additional adjustments to the purchase price allocation may be required and would most likely involve loans or property and equipment. As of March 6, 2015, the unpaid principal balance on purchased non-credit-impaired loans was $244.2 million . The fair value of the purchased non-credit-impaired loans was $241.4 million , resulting in a discount of $2.8 million recorded on these loans. This discount is being accreted into income over the life of the loans on an effective yield basis. The following table presents the acquired PCI loans as of the acquisition date (in thousands): Siuslaw March 6, 2015 Acquired PCI loans: Contractually required principal and interest payments $ 11,134 Nonaccretable difference (3,238 ) Cash flows expected to be collected 7,896 Accretable yield (2,239 ) Fair value of PCI loans $ 5,657 The following table presents certain unaudited pro forma information for illustrative purposes only, for the years ended December 31, 2015 and 2014 as if Siuslaw had been acquired on January 1, 2014 . This unaudited estimated pro forma financial information combines the historical results of Siuslaw with the Company’s consolidated historical results. Pro forma adjustments include, accretion of loan discount, accretion of investment premiums, amortization of deposit premium, amortization of CDI, reversal of acquisition expense, and reversal of historical recorded amounts for similar items, with all adjustments tax effected. The pro forma information is not indicative of what would have occurred had the acquisition actually occurred on January 1, 2014 . In particular, no adjustments have been made to eliminate the impact of other-than-temporary impairment losses and losses recognized on the sale of securities that may not have been necessary had the investment securities been recorded at fair value as of January 1, 2014 . The unaudited pro forma information does not consider any changes to the provision for credit losses resulting from recording loan assets at fair value. Additionally, Banner expects to achieve further operating cost savings and other business synergies, including revenue growth, as a result of the acquisition which are not reflected in the pro forma amounts that follow. As a result, actual amounts would have differed from the unaudited pro forma information presented (in thousands except per share amounts): Pro Forma Years Ended December 31 2015 2014 Total revenues (net interest income plus non-interest income) $ 308,153 $ 254,212 Net income $ 44,484 $ 58,703 Earnings per share - basic $ 1.85 $ 2.84 Earnings per share - diluted $ 1.85 $ 2.83 The operating results of the Company include the operating results produced by the acquired assets and assumed liabilities of Siuslaw for the period March 7, 2015 to December 31, 2015 . Disclosure of the amount of Siuslaw’s revenue and net income (excluding integration costs) included in the Company’s Consolidated Statements of Operations is impracticable due to the integration of the operations and accounting for this acquisition. Purchase 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 purchase). Five of the six branches are located in Coos County, Oregon and the sixth branch is located in Douglas County, Oregon. The purchase provided $212.1 million in deposit accounts, $87.9 million in loans, and $3.1 million in branch properties. Banner Bank received $127.6 million in cash from the transaction. The application of the acquisition method of accounting resulted in recognition of a CDI of $2.4 million and an acquisition bargain purchase gain of $9.1 million . 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 CDI was determined to have a useful life of approximately eight years and is being 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): Branch Purchase June 20, 2014 Total consideration $ — Fair value of assets acquired: Cash and cash equivalents $ 127,557 Loans receivable (contractual amount of $88.3 million) 87,923 Property and equipment 3,079 CDI 2,372 Other assets 275 Total assets acquired 221,206 Fair value of liabilities assumed: Deposits 212,085 Other liabilities 42 Total liabilities assumed 212,127 Net assets acquired 9,079 Acquisition bargain purchase gain $ (9,079 ) The primary reason for the Branch purchase was to continue the Company's growth strategy, including expanding its 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 Branch purchase from June 21, 2014 to December 31, 2015 . Pro forma results of operations for the years ended December 31, 2015 and 2014 , as if the Branch purchase had occurred on January 1, 2014 , have not been presented because historical financial information was not available. There were no PCI loans acquired in connection with the Branch purchase. Acquisition-Related Costs The following tables present the key components of acquisition-related costs in connection with the Branch purchase, the acquisition of Siuslaw and the acquisition of Starbuck, including AmericanWest, for the years ended December 31, 2015 , 2014 and 2013 (in thousands): Years Ended December 31 2015 2014 2013 Acquisition-related costs recognized in non-interest expense: Personnel severance/retention fees $ 6,577 $ — $ — Non-capitalized equipment and repairs 1,031 105 — Client communications 527 327 — Information/computer data services 2,875 334 — Payment and processing expenses 28 185 — Professional services 11,169 2,953 550 Miscellaneous 3,903 421 — $ 26,110 $ 4,325 $ 550 The Branch purchase $ — $ 1,784 $ 550 Siuslaw 2,000 748 — Starbuck 24,110 1,793 — $ 26,110 $ 4,325 $ 550

SECURITIES

SECURITIES	12 Months Ended
	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
SECURITIES	SECURITIES The amortized cost, gross unrealized losses and gains and estimated fair value of securities at December 31, 2015 and 2014 are summarized as follows (in thousands): December 31, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Trading: U.S. Government and agency obligations $ 1,230 $ 1,368 Municipal bonds 332 341 Corporate bonds 25,063 18,699 Mortgage-backed or related securities 12,705 13,663 Equity securities 14 63 $ 39,344 $ 34,134 Available-for-Sale: U.S. Government and agency obligations $ 30,211 $ 213 $ (193 ) $ 30,231 Municipal bonds 142,898 853 (432 ) 143,319 Corporate bonds 15,937 56 (12 ) 15,981 Mortgage-backed or related securities 919,318 4,056 (5,115 ) 918,259 Asset-backed securities 31,288 — (603 ) 30,685 Equity securities 88 10 — 98 $ 1,139,740 $ 5,188 $ (6,355 ) $ 1,138,573 Held-to-Maturity: U.S. Government and agency obligations $ 1,106 $ 5 $ — $ 1,111 Municipal bonds: 162,778 6,219 (191 ) 168,806 Corporate bonds 4,273 — — 4,273 Mortgage-backed or related securities 52,509 253 (325 ) 52,437 $ 220,666 $ 6,477 $ (516 ) $ 226,627 December 31, 2014 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Trading: U.S. Government and agency obligations $ 1,340 $ 1,505 Municipal bonds 1,405 1,440 Corporate bonds 27,995 19,118 Mortgage-backed or related securities 16,726 18,136 Equity securities 14 59 $ 47,480 $ 40,258 Available-for-Sale: U.S. Government and agency obligations $ 29,973 $ 8 $ (211 ) $ 29,770 Municipal bonds 49,959 190 (121 ) 50,028 Corporate bonds 5,000 18 — 5,018 Mortgage-backed or related securities 300,979 1,429 (1,598 ) 300,810 Asset-backed securities 25,513 167 (285 ) 25,395 $ 411,424 $ 1,812 $ (2,215 ) $ 411,021 Held-to-Maturity: U.S. Government and agency obligations $ 2,146 $ — $ (19 ) $ 2,127 Municipal bonds: 119,951 6,319 (48 ) 126,222 Corporate bonds 1,800 — — 1,800 Mortgage-backed or related securities 7,361 105 (7 ) 7,459 $ 131,258 $ 6,424 $ (74 ) $ 137,608 At December 31, 2015 and 2014 , the gross unrealized losses and the fair value for securities available-for-sale and held-to-maturity aggregated by the length of time that individual securities have been in a continuous unrealized loss position was as follows (in thousands): December 31, 2015 Less Than 12 Months 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Available-for-Sale: U.S. Government and agency obligations $ 8,707 $ (97 ) $ 10,489 $ (96 ) $ 19,196 $ (193 ) Municipal bonds 69,848 (426 ) 905 (6 ) 70,753 (432 ) Corporate bonds 5,153 (12 ) — — 5,153 (12 ) Mortgage-backed or related securities 533,143 (4,380 ) 68,562 (735 ) 601,705 (5,115 ) Asset-backed securities 20,893 (355 ) 9,792 (248 ) 30,685 (603 ) $ 637,744 $ (5,270 ) $ 89,748 $ (1,085 ) $ 727,492 $ (6,355 ) Held-to-Maturity: Municipal bonds $ 28,545 $ (188 ) $ 254 $ (3 ) $ 28,799 $ (191 ) Corporate bonds — — — — — — Mortgage-backed or related securities 34,493 (323 ) 255 (2 ) 34,748 (325 ) $ 63,038 $ (511 ) $ 509 $ (5 ) $ 63,547 $ (516 ) December 31, 2014 Less Than 12 Months 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Available-for-Sale: U.S. Government and agency obligations $ 15,983 $ (58 ) $ 9,847 $ (153 ) $ 25,830 $ (211 ) Municipal bonds 16,322 (61 ) 7,129 (60 ) 23,451 (121 ) Mortgage-backed or related securities 91,046 (236 ) 107,266 (1,362 ) 198,312 (1,598 ) Asset-backed securities — — 9,765 (285 ) 9,765 (285 ) $ 123,351 $ (355 ) $ 134,007 $ (1,860 ) $ 257,358 $ (2,215 ) Held-to-Maturity: U.S. Government and agency obligations $ — $ — $ 1,127 $ (19 ) $ 1,127 $ (19 ) Municipal bonds 9,821 (44 ) 592 (4 ) 10,413 (48 ) Mortgage-backed or related securities 1,018 (7 ) — — 1,018 (7 ) $ 10,839 $ (51 ) $ 1,719 $ (23 ) $ 12,558 $ (74 ) At December 31, 2015 , there were 242 securities—available-for-sale with unrealized losses, compared to 94 at December 31, 2014 and 114 at December 31, 2013 . At December 31, 2015 , there were 32 securities—held-to-maturity with unrealized losses, compared to 25 at December 31, 2014 and 36 at December 31, 2013 . Management does not believe that any individual unrealized loss as of December 31, 2015 , 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. Sales of securities—trading totaled $4.4 million with a resulting net loss of $690,000 for the year ended December 31, 2015 and totaled $2.4 million with a resulting net gain of $1,000 for the year ended December 31, 2014 . Sales of securities—trading for the year ended December 31, 2013 totaled $34.3 million with a resulting net gain of $1.5 million , 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. The Company did no t recognize any OTTI charges or recoveries on securities—trading during the years ended December 31, 2015 or 2014 . There were no securities—trading in a nonaccrual status at December 31, 2015 and 2014 . Net unrealized holding gains of $2.0 million were recognized in 2015 . Sales of securities—available-for-sale totaled $232.6 million with a resulting net gain of $126,000 for the year ended December 31, 2015 . Sales of securities—available-for-sale totaled $56.3 million with a resulting net gain of $41,000 for the year ended December 31, 2014 . Sales of securities—available-for-sale totaled $103.3 million with a resulting net loss of $116,000 for the year ended December 31, 2013 . There were no securities—available-for-sale in a nonaccrual status at December 31, 2015 and 2014 . There were no sales of securities—held-to-maturity during the years ended December 31, 2015 , 2014 or 2013 . There were no securities—held-to-maturity in a nonaccrual status at December 31, 2015 and 2014 . The amortized cost and estimated fair value of securities at December 31, 2015 , 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, 2015 Trading Available-for-Sale Held-to-Maturity Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Maturing in one year or less $ — $ — $ 12,522 $ 12,477 $ 4,986 $ 5,035 Maturing after one year through five years 8,790 9,361 278,205 277,056 13,707 13,810 Maturing after five years through ten years 3,480 3,823 185,919 184,948 83,478 84,158 Maturing after ten years through twenty years 1,997 2,188 338,069 338,362 99,614 104,460 Maturing after twenty years 25,063 18,699 324,937 325,632 18,881 19,164 39,330 34,071 1,139,652 1,138,475 220,666 226,627 Equity securities 14 63 88 98 $ 39,344 $ 34,134 $ 1,139,740 $ 1,138,573 $ 220,666 $ 226,627 The following table presents, as of December 31, 2015 , 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 $ 204,894 $ 201,149 $ 210,422 Interest rate swap counterparties 13,687 13,284 13,687 Repurchase transaction accounts 110,140 109,956 110,146 Other 1,970 1,895 1,970 Total pledged securities $ 330,691 $ 326,284 $ 336,225

LOANS RECEIVABLE AND THE ALLOWA

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES	12 Months Ended
	Dec. 31, 2015
Receivables [Abstract]
LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES	LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES Loans receivable at December 31, 2015 and 2014 are summarized as follows (dollars in thousands): December 31, 2015 December 31, 2014 Amount Percent of Total Amount Percent of Total Commercial real estate: Owner-occupied $ 1,327,807 18.2 % $ 546,783 14.3 % Investment properties 1,765,353 24.1 856,942 22.3 Multifamily real estate 472,976 6.5 167,524 4.4 Commercial construction 72,103 1.0 17,337 0.4 Multifamily construction 63,846 0.9 60,193 1.6 One- to four-family construction 278,469 3.8 219,889 5.7 Land and land development: Residential 126,773 1.7 102,435 2.7 Commercial 33,179 0.5 11,152 0.3 Commercial business 1,207,944 16.5 723,964 18.9 Agricultural business, including secured by farmland 376,531 5.1 238,499 6.2 One- to four-family residential 952,633 13.0 537,108 14.1 Consumer: Consumer secured by one- to four-family 478,420 6.5 222,205 5.8 Consumer—other 158,470 2.2 127,003 3.3 Total loans outstanding 7,314,504 100.0 % 3,831,034 100.0 % Less allowance for loan losses (78,008 ) (75,907 ) Net loans $ 7,236,496 $ 3,755,127 Loan amounts are net of unearned loan fees in excess of unamortized costs of $5.5 million at December 31, 2015 and $5.8 million at December 31, 2014 . Net loans include net discounts on acquired loans of $43.7 million and $148,000 as of December 31, 2015 and 2014 , respectively. 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 balances of $7.9 million and $8.6 million for the years ended December 31, 2015 and 2014 , respectively. Purchased credit-impaired loans: The outstanding contractual unpaid principal balance of PCI loans, excluding acquisition accounting adjustments, was $83.4 million at December 31, 2015 . The carrying balance of PCI loans was $58.6 million at December 31, 2015 . There were no PCI loans at December 31, 2014 . The following table presents the changes in the accretable yield for PCI loans for the years ended December 31, 2015 and 2014 (in thousands): Years Ended December 31 2015 2014 Balance, beginning of period $ — $ — Additions 13,310 — Accretion to interest income (2,202 ) — Disposals and other (1,238 ) — Reclassifications from non-accretable difference 505 — Balance, end of period $ 10,375 $ — As of December 31, 2015 , the non-accretable difference between the contractually required payments and cash flows expected to be collected was $29.5 million . 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. 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 comprised of loans on nonaccrual, TDRs, and loans that are 90 days or more past due, but are still on accrual. Purchase credit-impaired loans are consider performing within the scope of the PCI accounting guidance and are not included in the impaired loan tables. The following tables provide additional information on impaired loans, excluding purchased credit impaired loans, with and without specific allowance reserves at December 31, 2015 and 2014 . Recorded investment includes the unpaid principal balance or the carrying amount of loans less charge-offs and net deferred loan fees (in thousands): December 31, 2015 Unpaid Principal Balance Recorded Investment Related Allowance Without Allowance (1) With Allowance (2) Commercial real estate: Owner-occupied $ 1,465 $ — $ 1,416 $ 70 Investment properties 8,740 2,503 5,846 602 Multifamily real estate 359 — 357 71 Commercial construction 1,141 1,069 — — One- to four-family construction 1,741 — 1,741 161 Land and land development: Residential 3,540 750 1,634 444 Commercial 1,628 1,027 — Commercial business 2,266 538 1,184 150 Agricultural business/farmland 1,309 544 697 43 One- to four-family residential 17,897 2,206 14,418 736 Consumer: Consumer secured by one- to four-family 776 — 716 23 Consumer—other 433 — 351 7 $ 41,295 $ 8,637 $ 28,360 $ 2,307 December 31, 2014 Unpaid Principal Balance Recorded Investment Related Allowance Without Allowance (1) With Allowance (2) Commercial real estate: Owner-occupied $ 1,598 $ 966 $ 582 $ 24 Investment properties 6,458 30 6,023 729 Multifamily real estate 786 — 786 86 One- to four-family construction 3,923 — 3,923 640 Land and land development: Residential 3,710 1,275 1,280 346 Commercial business 1,502 — 1,276 128 Agricultural business/farmland 1,597 744 854 26 One- to four-family residential 27,855 1,865 24,529 1,032 Consumer: Consumer secured by one- to four-family 1,256 73 1,077 75 Consumer—other 634 138 470 6 $ 49,319 $ 5,091 $ 40,800 $ 3,092 (1) Loans without an allowance reserve have been individually evaluated for impairment and that evaluation concluded that no reserve was needed. (2) Includes general reserves for loans evaluated in pools of homogeneous loans and loans with a specific reserve allowance. 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 less costs to sell to establish realizable value. The following tables summarize our average recorded investment and interest income recognized on impaired loans by loan class for the years ended December 31, 2015 , 2014 and 2013 (in thousands): Year Ended December 31, 2015 Year Ended December 31, 2014 Year Ended December 31, 2013 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Commercial real estate: Owner-occupied $ 1,467 $ 9 $ 1,841 $ 12 $ 2,761 $ 12 Investment properties 8,003 303 6,145 315 8,977 241 Multifamily real estate 362 18 795 45 5,705 298 One- to four-family construction 1,463 114 2,655 118 5,870 239 Land and land development: Residential 2,406 49 2,872 89 6,053 221 Commercial 931 — — — — — Commercial business 1,667 35 1,328 41 2,236 59 Agricultural business/farmland 1,143 19 1,866 — 110 8 One- to four-family residential 17,770 630 26,093 870 40,557 1,063 Consumer: Consumer secured by one- to four-family 736 11 1,248 19 1,403 25 Consumer—other 392 18 597 19 677 29 $ 36,340 $ 1,206 $ 45,440 $ 1,528 $ 74,349 $ 2,195 The following tables present TDRs at December 31, 2015 and 2014 (in thousands): December 31, 2015 December 31, 2014 Accrual Status Nonaccrual Status Total TDRs Accrual Nonaccrual Total Commercial real estate: Owner-occupied $ 181 $ 104 $ 285 $ 183 $ 109 $ 292 Investment properties 5,834 13 5,847 6,021 32 6,053 Multifamily real estate 357 — 357 786 — 786 One- to four-family construction 1,741 — 1,741 3,923 — 3,923 Land and land development: Residential 1,151 483 1,634 1,279 525 1,804 Commercial business 624 — 624 739 87 826 Agricultural business/farmland 545 277 822 — — — One- to four-family residential 11,025 1,428 12,453 15,793 1,363 17,156 Consumer: Consumer secured by one- to four-family 147 14 161 233 117 350 Consumer—other 172 — 172 197 116 313 $ 21,777 $ 2,319 $ 24,096 $ 29,154 $ 2,349 $ 31,503 As of December 31, 2015 and 2014 , the Company had commitments to advance funds up to an additional amount of $237,000 and $2.1 million , respectively, related to TDRs. The following table presents new TDRs that occurred during the years ended December 31, 2015 and 2014 (dollars in thousands): Year Ended December 31, 2015 Year Ended December 31, 2014 Number of Contracts Pre-modification Outstanding Recorded Investment Post-modification Outstanding Recorded Investment Number of Pre-modification Outstanding Recorded Investment Post-modification Outstanding Recorded Investment Recorded Investment (1) (2) Commercial real estate: Owner-occupied — $ — $ — 1 $ 203 $ 203 One- to four-family construction — — — 10 2,153 2,153 Land and land development: Residential 2 1,302 483 — — — Commercial business — — — 1 100 100 Agricultural business/farmland 3 822 822 — — — One- to four-family residential 2 431 431 4 905 862 Consumer: Consumer - other — — — 1 9 9 7 $ 2,555 $ 1,736 17 $ 3,370 $ 3,327 (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, 2015 and 2014 , 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 2015 2014 Number of Loans Amount Number of Loans Amount Agricultural business/farmland 2 $ 277 — $ — One- to four-family residential 1 387 — — Total 3 $ 664 — $ — 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 2015 . 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 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, 2015 (in thousands): For the Year Ended December 31, 2015 Commercial Real Estate Multifamily Real Estate Construction and Land Commercial Business Agricultural Business One- to Four-Family Residential Consumer Unallocated Total Allowance for loan losses: Beginning balance $ 18,784 $ 4,562 $ 25,545 $ 12,043 $ 3,821 $ 5,447 $ 483 $ 5,222 $ 75,907 Provision for loan losses 1,177 (480 ) 666 1,611 (878 ) (1,068 ) 1,363 (2,391 ) — Recoveries 819 113 1,811 948 1,927 772 570 — 6,960 Charge-offs (64 ) — (891 ) (746 ) (1,225 ) (419 ) (1,514 ) — (4,859 ) Ending balance $ 20,716 $ 4,195 $ 27,131 $ 13,856 $ 3,645 $ 4,732 $ 902 $ 2,831 $ 78,008 December 31, 2015 Commercial Real Estate Multifamily Construction and Land Commercial Business Agricultural Business One- to Four-Family Residential Consumer Unallocated Total Allowance individually evaluated for impairment $ 605 $ 71 $ 418 $ 69 $ — $ 728 $ 29 $ — $ 1,920 Allowance collectively evaluated for impairment 20,111 4,124 26,713 13,732 3,645 4,004 873 2,831 76,033 Allowance for purchased credit-impaired loans — — — 55 — — — — 55 Total allowance for loan losses $ 20,716 $ 4,195 $ 27,131 $ 13,856 $ 3,645 $ 4,732 $ 902 $ 2,831 $ 78,008 December 31, 2015 Commercial Real Estate Multifamily Construction and Land Commercial Business Agricultural Business One- to Four-Family Residential Consumer Unallocated Total Loan balances: Loans individually evaluated for impairment $ 8,519 $ 357 $ 4,669 $ 2,223 $ 544 $ 12,185 $ 319 $ — $ 28,816 Loans collectively evaluated for impairment 3,043,656 470,625 564,051 1,198,419 374,458 939,382 636,497 — 7,227,088 Purchased credit-impaired loans 40,985 1,994 5,650 7,302 1,529 1,066 74 — 58,600 Total loans $ 3,093,160 $ 472,976 $ 574,370 $ 1,207,944 $ 376,531 $ 952,633 $ 636,890 $ — $ 7,314,504 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 Real Estate Multifamily Construction and Land Commercial Business Agricultural Business One- to Four-Family Residential Consumer Unallocated Total 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 Real Estate Multifamily Construction and Land Commercial Business Agricultural Business One- to Four-Family Residential Consumer Unallocated Total 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 Real Estate Multifamily Construction and Land Commercial Business Agricultural Business One- to Four-Family Residential Consumer Unallocated Total Loan balances: Loans individually evaluated for impairment $ 7,171 $ 786 $ 6,477 $ 739 $ 744 $ 17,848 $ 681 $ — $ 34,446 Loans collectively evaluated for impairment 1,396,554 166,738 404,529 723,225 237,755 519,260 348,527 — 3,796,588 Total loans $ 1,403,725 $ 167,524 $ 411,006 $ 723,964 $ 238,499 $ 537,108 $ 349,208 $ — $ 3,831,034

REAL ESTATE OWNED, HELD FOR SAL

REAL ESTATE OWNED, HELD FOR SALE, NET	12 Months Ended
	Dec. 31, 2015
Real Estate [Abstract]
REAL ESTATE OWNED, HELD FOR SALE, NET	REAL ESTATE OWNED, HELD FOR SALE, NET The following table presents the changes in REO, net of valuation allowance, for the years ended December 31, 2015 , 2014 and 2013 (in thousands): Years Ended December 31 2015 2014 2013 Balance, beginning of period $ 3,352 $ 4,044 $ 15,778 Additions from loan foreclosures 4,351 3,264 3,166 Additions from capitalized costs 298 30 348 Additions from acquisitions 8,231 — — Proceeds from dispositions of REO (4,740 ) (4,923 ) (16,944 ) Gain on sale of REO 351 973 2,481 Valuation adjustments in the period (216 ) (36 ) (785 ) Balance, end of period $ 11,627 $ 3,352 $ 4,044

PROPERTY AND EQUIPMENT, NET

PROPERTY AND EQUIPMENT, NET	12 Months Ended
	Dec. 31, 2015
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, 2015 and 2014 are summarized as follows (in thousands): December 31 2015 2014 Land $ 38,992 $ 21,969 Buildings and leasehold improvements 160,075 98,901 Furniture and equipment 79,018 72,152 278,085 193,022 Less accumulated depreciation (110,481 ) (101,837 ) Property and equipment, net $ 167,604 $ 91,185 The Company’s depreciation expense related to property and equipment was $10.0 million , $8.1 million , and $7.5 million for the years ended December 31, 2015 , 2014 and 2013 , respectively. The Company’s rental expense was $10.2 million , $7.6 million , and $7.3 million for the years ended December 31, 2015 , 2014 and 2013 , respectively. The Company’s obligations under long-term property leases are as follows: Year Amount 2016 $ 14.3 million 2017 12.9 million 2018 10.7 million 2019 7.8 million 2020 6.6 million Thereafter 23.0 million Total $ 75.3 million

DEPOSITS

DEPOSITS	12 Months Ended
	Dec. 31, 2015
Banking and Thrift [Abstract]
DEPOSITS	DEPOSITS Deposits consist of the following at December 31, 2015 and 2014 (in thousands): December 31 2015 2014 Non-interest-bearing checking $ 2,619,618 $ 1,298,866 Interest-bearing checking 1,159,846 439,480 Regular savings accounts 1,284,642 901,142 Money market accounts 1,637,092 488,946 Total transaction and savings accounts 6,701,198 3,128,434 Certificates of deposit: Certificates of deposit less than or equal to the FDIC insured limit of $250,000 1,168,495 633,345 Certificates of deposit greater than the FDIC insured limit of $250,000 185,375 137,171 Total certificates of deposit 1,353,870 770,516 Total deposits $ 8,055,068 $ 3,898,950 Included in total deposits: Public fund transaction accounts $ 209,430 $ 102,854 Public fund interest-bearing certificates 31,281 35,346 Total public deposits $ 240,711 $ 138,200 Total brokered deposits $ 162,936 $ 4,799 Deposits at December 31, 2015 and 2014 included deposits from the Company’s directors, executive officers and related entities totaling $6.6 million and $6.2 million , respectively. Scheduled maturities and weighted average interest rates of certificate accounts at December 31, 2015 are as follows (dollars in thousands): December 31, 2015 Amount Weighted Average Rate Maturing in one year or less $ 985,193 0.48 % Maturing after one year through two years 226,381 0.88 Maturing after two years through three years 88,184 1.05 Maturing after three years through four years 24,981 1.17 Maturing after four years through five years 25,917 1.26 Maturing after five years 3,214 1.10 Total certificates of deposit $ 1,353,870 0.61 %

ADVANCES FROM FEDERAL HOME LOAN

ADVANCES FROM FEDERAL HOME LOAN BANK OF DES MOINES	12 Months Ended
	Dec. 31, 2015
Advances from Federal Home Loan Banks [Abstract]
ADVANCES FROM FEDERAL HOME LOAN BANK OF DES MOINES	ADVANCES FROM FEDERAL HOME LOAN BANK OF DES MOINES Utilizing a blanket pledge, qualifying loans receivable at December 31, 2015 and 2014 , were pledged as security for FHLB borrowings and there were no securities pledged as collateral as of December 31, 2015 or 2014 . At December 31, 2015 and 2014 , FHLB advances were scheduled to mature as follows (dollars in thousands): December 31 2015 2014 Maturing in one year or less $ 107,600 $ 32,000 Maturing after one year through three years 25,000 — Maturing after three years through five years — — Maturing after five years 188 196 Total FHLB advances, at par 132,788 32,196 Fair value adjustment 593 54 Total FHLB advances, carried at fair value $ 133,381 $ 32,250 The maximum amount outstanding from the FHLB advances at month end for the years ended December 31, 2015 and 2014 was $221.6 million and $105.5 million . The average FHLB advances balance outstanding for the years ended December 31, 2015 and 2014 was $45.0 million and $39.1 million , respectively. The average contractual interest rate on the FHLB advances for the years ended December 31, 2015 and 2014 was 0.69% and 0.32% , respectively. As of December 31, 2015 , 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 similarly may borrow up to 35% of its total assets, also contingent on collateral and FHLB stock. At December 31, 2015 , the maximum total FHLB credit line was $1.77 billion and $28.0 million for Banner Bank and Islanders Bank, respectively.

OTHER BORROWINGS

OTHER BORROWINGS	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
OTHER BORROWINGS	OTHER BORROWINGS Other borrowings consist of retail and wholesale repurchase agreements, other term borrowings and Federal Reserve Bank borrowings. Repurchase Agreements: At December 31, 2015 , retail repurchase agreements carry interest rates ranging from 0.15% to 0.40% . In addition to the retail repurchase agreements, Banner Bank had one wholesale repurchase agreement with an interest rate of 2.15% . These repurchase agreements are secured by the pledge of certain mortgage-backed and agency securities with a carrying value of $110.1 million . Banner Bank has the right to pledge or sell these securities, but it must replace them with substantially the same securities. 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, 2015 , based upon available unencumbered collateral, Banner Bank was eligible to borrow $735.0 million from the Federal Reserve Bank, although, at that date, as well as at December 31, 2014 , the Bank had no funds borrowed under this or other borrowing arrangements. At December 31, 2015 , Banner Bank had an uncommitted federal funds line of credit agreement with another financial institution totaling $25.0 million , while Islanders Bank had an uncommitted federal funds line of credit agreement with another financial institution totaling $5.0 million . No balances were outstanding under these agreements as of December 31, 2015 and 2014 . Availability of lines is subject to federal funds balances available for loan and continued borrower eligibility. These lines are intended to support short-term liquidity needs and the agreements may restrict consecutive day usage. A summary of all other borrowings at December 31, 2015 and 2014 by the period remaining to maturity is as follows (dollars in thousands): At or for the Years Ended December 31 2015 2014 Amount Weighted Average Rate Amount Weighted Average Rate Repurchase agreements: Maturing in one year or less $ 93,325 0.19 % $ 77,185 0.20 % Maturing after one year through two years — — — — Maturing after two years 5,000 2.15 — — Total year-end outstanding $ 98,325 0.29 $ 77,185 0.20 Average outstanding $ 94,182 0.22 $ 83,965 0.20 Maximum outstanding at any month-end 102,474 n/a 89,921 n/a

JUNIOR SUBORDINATED DEBENTURES

JUNIOR SUBORDINATED DEBENTURES AND MANDATORILY REDEEMABLE TRUST PREFERRED SECURITIES	12 Months Ended
	Dec. 31, 2015
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, 2015 , the Company had nine wholly-owned subsidiary grantor trusts (the Trusts), which had issued $136.0 million of trust preferred securities to third parties, as well as $4.2 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 (TPS) 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, 2015 . At December 31, 2015 , the Trusts comprised $88.3 million , or 14.0% of the Company’s total risk-based capital. The following table is a summary of trust preferred securities at December 31, 2015 (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 (1) Current Interest Rate Reset Period Interest Rate Spread Banner Capital Trust II $ 15,000 $ 464 $ 15,464 2033 3.96 % Quarterly Three-month LIBOR + 3.35% Banner Capital Trust III 15,000 465 15,465 2033 3.51 Quarterly Three-month LIBOR + 2.90% Banner Capital Trust IV 15,000 465 15,465 2034 3.46 Quarterly Three-month LIBOR + 2.85% Banner Capital Trust V 25,000 774 25,774 2035 2.18 Quarterly Three-month LIBOR + 1.57% Banner Capital Trust VI 25,000 774 25,774 2037 2.23 Quarterly Three-month LIBOR + 1.62% Banner Capital Trust VII 25,000 774 25,774 2037 1.99 Quarterly Three-month LIBOR + 1.38% Siuslaw Statutory Trust I 8,000 248 8,248 2034 3.31 Quarterly Three-month LIBOR + 2.70% Greater Sacramento Bancorp Statutory Trust I 4,000 124 4,124 2033 3.96 Quarterly Three-month LIBOR + 3.35% Greater Sacramento Bancorp Statutory Trust II 4,000 124 4,124 2035 2.29 Quarterly Three-month LIBOR + 1.68% Total TPS liability at par $ 136,000 $ 4,212 140,212 2.76 % Fair value adjustment (47,732 ) Total TPS liability at fair value $ 92,480 (1) All of the Company's trust preferred securities are eligible for redemption.

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The following table presents the components of the provision for income taxes included in the Consolidated Statements of Operations for the years ended December 31, 2015 , 2014 and 2013 (in thousands): Years Ended December 31 2015 2014 2013 Current Federal $ 24,683 $ 23,411 $ 11,829 State 1,399 1,444 292 Total Current 26,082 24,855 12,121 Deferred Federal (3,310 ) 2,764 10,936 State (23 ) (567 ) 1,132 Total Deferred (3,333 ) 2,197 12,068 Increase (decrease) in valuation allowance — — — Provision for income taxes $ 22,749 $ 27,052 $ 24,189 The following tables present the reconciliation of the federal statutory rate to the actual effective rate for the years ended December 31, 2015 , 2014 and 2013 (dollars in thousands): Years Ended December 31 2015 2014 2013 Federal income tax statutory rate 35.0 % 35.0 % 35.0 % Increase (decrease) in tax rate due to: Tax-exempt interest (3.9 ) (2.6 ) (2.4 ) Investment in life insurance (1.3 ) (0.8 ) (1.0 ) State income taxes, net of federal tax offset 1.1 1.1 1.2 Tax credits (1.6 ) (0.8 ) (0.9 ) Merger and acquisition costs 1.9 0.7 — Other 2.3 0.7 2.5 Effective income tax rate 33.5 % 33.3 % 34.4 % 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, 2015 and 2014 (in thousands): December 31 2015 2014 Deferred tax assets: Loan loss and REO $ 33,312 $ 26,536 Deferred compensation 19,253 9,223 Net operating loss carryforward 91,893 17,577 Federal and state tax credits 7,877 3,676 State net operating losses 8,692 1,009 Loan discount 13,412 (1,190 ) Other 5,620 1,344 Total deferred tax assets 180,059 58,175 Deferred tax liabilities: FHLB stock dividends — (4,805 ) Depreciation (1,103 ) (4,479 ) Deferred loan fees, servicing rights and loan origination costs (9,884 ) (7,843 ) Intangibles (13,320 ) (975 ) Financial instruments accounted for under fair value accounting (17,112 ) (15,611 ) Unrealized (gain) loss on securities - available-for-sale (1,475 ) 145 Total deferred tax liabilities (42,894 ) (33,568 ) Deferred income tax asset 137,165 24,607 Valuation allowance (2,195 ) — Deferred tax asset, net $ 134,970 $ 24,607 At December 31, 2015 , the Company has federal net operating loss carryforwards of approximately $262.5 million . The Company has $23.0 million state net operating loss carryforwards, which the Company has established a $2.2 million valuation reserve against. The federal and state net operating losses will expire, if unused, by the end of 2034 . The Company has federal general business credit carryforwards of $3.3 million , which will expire, if unused, by the end of 2031 . The Company also has federal alternative minimum tax credit carryforwards of $4.2 million , which are available to reduce future federal regular income taxes, if any, over an indefinite period. Additionally, at December 31, 2015 , the Company has state alternative minimum tax credit and other state credit carryovers of $353,000 . At December 31, 2014 , the Company had federal and state net operating loss carryforwards of approximately $50.2 million and $21.2 million , respectively, and federal general business credits carryforwards of $2.7 million . At that same date, the Company also had alternative minimum tax credit carryforwards of approximately $900,000 . As a consequence of our acquisition of Starbuck Bancshares, Inc., the Company experienced a change in control within the meaning of Section 382 of the Code. In addition, the underlying Section 382 limitations at Starbuck Bancshares, Inc. level continue to apply to the Company. Section 382 limits the ability of a corporate taxpayer to use net operating loss carryforwards, general business credits, and recognized built-in-losses, on an annual basis, 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 is limited to utilizing $21.5 million (after the application of the Section 382 limitations carried over from Starbuck Bancshares, Inc.) of federal net operating loss carryforwards, general business credits, and recognized built-in losses. The Company has provided a $2.2 million valuation reserve against the portion of its various state net operating loss carryforwards and tax credits that it believes it is more likely than not that it will not realize the benefit because the application of the Section 382 limitations at the state level is based on future apportionment rates. In addition, as a consequence of Banner's capital raise in June 2010, the Company experienced a change in control within the meaning of Section 382 of the Code. As a result of the Section 382 limitation, the Company is limited to utilizing $6.9 million of net operating loss carryforwards which existed prior to the acquisition of Starbuck Bancshares, Inc., on an annual basis. Based on its analysis, the Company believes it is more likely than not that the June 2010 change in control will not impact its ability to utilize all of the related available net operating loss carryforwards, general business credits, and recognized built-in-losses. Retained earnings at December 31, 2015 and 2014 included 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, 2015 . 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 Internal Revenue Service (IRS) related to amended 2006, 2008 and 2009 federal income tax returns. Review of the amended federal returns was completed by the 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, 2015
Compensation and Retirement Disclosure [Abstract]
EMPLOYEE BENEFIT PLANS	EMPLOYEE BENEFIT PLANS Employee Retirement Plans: Substantially all of the Company’s and the Banks' 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, 2015 , 2014 and 2013 , $2.8 million , $1.4 million and $1.0 million , respectively, was expensed for 401(k) contributions. The Board of Directors has elected to make a 4% of eligible compensation matching contribution for 2016 . 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 Company is obligated to pay to the designated beneficiary the benefits set forth under the plan. For the years ended December 31, 2015 , 2014 and 2013 , expense recorded for supplemental retirement and salary continuation plan benefits totaled $1.3 million , $1.2 million , and $1.5 million , respectively. At December 31, 2015 and 2014 , liabilities recorded for the various supplemental retirement and salary continuation plan benefits totaled $39.0 million and $14.2 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 $6.9 million at December 31, 2015 and $6.7 million at December 31, 2014 . At December 31, 2015 and 2014 , liabilities recorded in connection with deferred compensation plan benefits totaled $8.4 million ( $6.9 million in contra-equity) and $8.2 million ( $6.7 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, 2015 and 2014 , the cash surrender value of these policies was $156.9 million and $63.8 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.

STOCK-BASED COMPENSATION PLANS

STOCK-BASED COMPENSATION PLANS	12 Months Ended
	Dec. 31, 2015
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 its shareholders: • 2001 Stock Option Plan (the SOP). • 2006 Long Term Incentive Plan. • 2012 Restricted Stock and Incentive Bonus Plan. • 2014 Omnibus 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 share grants, restricted stock unit grants, and stock options. Stock Options Under the SOP, Banner reserved 68,571 shares for issuance pursuant to the exercise of stock options to be granted to directors and employees. 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, 2015 , 2014 and 2013 , the Company did no t 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, 2015 , 2014 and 2013 there were no stock option compensation expenses recorded. A summary of the Company’s stock option award activity for the years ended December 31, 2013 , 2014 and 2015 follows: Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term, In Years Aggregate Intrinsic Value 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 1.90 n/a Granted — — Exercised — — Forfeited (5,664 ) 197.11 Outstanding at December 31, 2015 5,000 216.16 n/a n/a Outstanding at December 31, 2015 , net of expected forfeitures — — n/a n/a Exercisable at December 31, 2015 5,000 216.16 1.58 — 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, 2015 , 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 $ 216.16 $ 216.16 5,000 5,000 $ 216.16 1.6 years During the year ended December 31, 2015 , 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 SOP. 2006 Long-Term Incentive Plan In June 2006, the Board of Directors adopted the Banner Corporation 2006 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. The primary objective of the plan was 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 Banner common 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 a net reversal of compensation expense of $103,000 for the year ended December 31, 2015 compared to compensation expense of $89,000 for the year ended December 31, 2014. The reversal of compensation expense in 2015 was due to changes in the market value of Banner common stock. As of December 31, 2015, all SAR awards have been settled and there was no remaining liability for SARs. 2012 Restricted Stock and Incentive Bonus Plan Under the 2012 Restricted Stock and Incentive Bonus Plan (2012 Restricted Stock 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 2012 Restricted Stock Plan have a minimum vesting period of three years. The 2012 Restricted Stock Plan will continue in effect for a term of ten years, after which no further awards may be granted. 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. Vesting requirements may include time-based conditions, performance-based conditions, or market-based conditions. As of December 31, 2015 , the Company had granted 295,123 shares of restricted stock from the 2012 Restricted Stock Plan (as amended and restated), of which 181,305 shares had vested and 113,818 shares remain unvested. 2014 Omnibus Incentive Plan The 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 the exercise of awards. As of December 31, 2015 , 119,765 restricted stock shares and 7,331 restricted stock units have been granted under the 2014 Plan of which 9,352 restricted stock shares have vested. The expense associated with all restricted stock grants was $3.5 million , $2.7 million and $1.5 million respectively, for the years ended December 31, 2015 , 2014 and 2013 . Unrecognized compensation expense for these awards as of December 31, 2015 was $6.9 million and will be amortized over the next 35 months. A summary of the Company's Restricted Stock/Unit award activity during the years ended December 31, 2013 , 2014 and 2015 follows: Shares/Units Weighted Average Grant-Date Fair Value 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 ) 31.00 Unvested at December 31, 2014 195,106 32.83 Granted 155,183 45.59 Vested (109,416 ) 30.28 Forfeited (9,311 ) 39.07 Unvested at December 31, 2015 231,562 42.33

PREFERRED STOCK AND RELATED WAR

PREFERRED STOCK AND RELATED WARRANT	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
PREFERRED STOCK AND RELATED WARRANT	PREFERRED STOCK AND RELATED WARRANT On November 21, 2008, as part of the Capital Purchase Program, the Company entered into a Purchase Agreement with U.S. Treasury pursuant to which the Company issued and sold 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 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. 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 U.S. 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 REQUIREMENTS

REGULATORY CAPITAL REQUIREMENTS	12 Months Ended
	Dec. 31, 2015
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. 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, 2015: The Company—consolidated: Total capital to risk-weighted assets $ 1,139,554 13.63 % $ 668,941 8.00 % n/a n/a Tier 1 capital to risk-weighted assets 1,057,597 12.65 501,706 6.00 n/a n/a Tier 1 common equity to risk-weighted assets 1,013,971 12.13 376,279 4.50 n/a n/a Tier 1 capital to average leverage assets 1,057,597 11.06 382,617 4.00 n/a n/a Banner Bank: Total capital to risk- weighted assets 1,030,601 12.61 653,606 8.00 $ 817,008 10.00 Tier 1 capital to risk- weighted assets 950,865 11.64 490,205 6.00 653,606 8.00 Tier 1 common equity to risk-weighted assets 950,865 11.64 367,653 4.50 531,055 6.50 Tier 1 capital to average leverage assets 950,865 10.23 371,807 4.00 464,759 5.00 Islanders Bank: Total capital to risk- weighted assets 38,448 20.31 15,146 8.00 18,932 10.00 Tier 1 capital to risk- weighted assets 36,227 19.14 11,359 6.00 15,146 8.00 Tier 1 common equity to risk-weighted assets 36,227 19.14 8,520 4.50 12,306 6.50 Tier 1 capital to average leverage assets 36,227 13.38 10,826 4.00 13,533 5.00 December 31, 2014: The Company—consolidated: Total capital to risk-weighted assets $ 684,583 16.80 % $ 326,071 8.00 % n/a n/a Tier 1 capital to risk-weighted assets 633,317 15.54 163,036 4.00 n/a n/a Tier 1 capital to average leverage assets 633,317 13.41 188,885 4.00 n/a n/a Banner Bank: Total capital to risk- weighted assets 605,997 15.53 312,220 8.00 $ 390,274 10.00 % Tier 1 capital to risk- weighted assets 556,897 14.27 156,110 4.00 234,165 6.00 Tier 1 capital to average leverage assets 556,897 12.42 179,304 4.00 224,130 5.00 Islanders Bank: Total capital to risk- weighted assets 36,590 19.92 14,693 8.00 18,367 10.00 Tier 1 capital to risk- weighted assets 34,332 18.69 7,347 4.00 11,020 6.00 Tier 1 capital to average leverage assets 34,332 13.68 10,040 4.00 12,550 5.00 At December 31, 2015 , Banner Corporation and the Banks each exceeded all regulatory capital adequacy requirements. There have been no conditions or events since December 31, 2015 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 Banner's ability and the ability of the Banks 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), unless an election is made 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 the first quarter of 2015, we elected to permanently opt-out of the inclusion of AOCI in our capital calculations, to reduce the impact of market volatility on our regulatory capital levels. The new requirements also include changes in the risk-weights of certain 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 (up from 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, total capital and leverage ratios, Banner and each of 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 by that amount until fully implemented in January 2019.

OTHER INTANGIBLE ASSETS AND MOR

OTHER INTANGIBLE ASSETS AND MORTGAGE SERVICING RIGHTS	12 Months Ended
	Dec. 31, 2015
Other Intangible Assets and Mortgage Servicing Rights [Abstract]
OTHER INTANGIBLE ASSETS AND MORTGAGE SERVICING RIGHTS	GOODWILL, OTHER INTANGIBLE ASSETS AND MORTGAGE SERVICING RIGHTS Goodwill and Other Intangible Assets: At December 31, 2015 , intangible assets are comprised of goodwill and CDI acquired in business combinations. Goodwill represents the excess of the total purchase price paid over the fair value of the assets acquired, net of the fair values of liabilities assumed, and is not amortized but is reviewed annually for impairment. At December 31, 2015 , the Company completed it's qualitative assessment of goodwill and concluded that it is more likely than not that the fair value of Banner, the reporting unit, exceeds the carrying value. Additions to goodwill during 2015 relate to the AmericanWest and Siuslaw acquisitions. Banner has identified a single reporting unit for the purposes of its goodwill impairment evaluation. See Note 3, Business Combinations, for additional information on the acquisition and purchase price allocation. The Company amortizes CDI over their estimated useful lives and reviews them at least annually for events or circumstances that could impair their value. The CDI assets shown in the table below represent the value ascribed to the long-term deposit relationships acquired in various bank acquisitions. The additions in the table below relate to the Branch purchase in 2014 and the acquisition of Siuslaw and AmericanWest in 2015. These intangible assets are being amortized using an accelerated method over estimated useful lives of three to ten years. The CDI assets are not estimated to have a significant residual value. The following table summarizes the changes in the Company’s goodwill and CDI for the years ended December 31, 2013 , 2014 and 2015 (in thousands): Goodwill CDI Total 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 Additions through acquisition 247,738 37,395 285,133 Amortization — (3,164 ) (3,164 ) Other changes (1) — (300 ) (300 ) Balance, December 31, 2015 $ 247,738 $ 36,762 $ 284,500 (1) Acquired CDI from AmericanWest was adjusted for a branch that was subsequently sold. Estimated amortization expense in future years with respect to existing intangibles as of December 31, 2015 (in thousands): Year ended: CDI 2016 $ 7,061 2017 6,332 2018 5,610 2019 4,889 Thereafter 12,870 Net carrying amount $ 36,762 Mortgage servicing rights are reported in other assets. Mortgage servicing rights are initially recognized 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 2015 and 2014 , the Company did no t 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. Unpaid principal balance of loans for which mortgage servicing rights have been recognized totaled $1.86 billion and $1.28 billion at December 31, 2015 and 2014 , respectively. Custodial accounts maintained in connection with this servicing totaled $8.7 million and $6.5 million at December 31, 2015 and 2014 , respectively. An analysis of the mortgage servicing rights for the years ended December 31, 2015 , 2014 and 2013 is presented below (in thousands): Years Ended December 31 2015 2014 2013 Balance, beginning of the year $ 9,030 $ 8,086 $ 6,244 Amounts capitalized 5,313 3,023 2,913 Additions through acquisition 2,172 — — Amortization (1) (3,220 ) (2,079 ) (2,371 ) Valuation adjustments in the period — — 1,300 Balance, end of the year (2) $ 13,295 $ 9,030 $ 8,086 (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) There was no valuation allowance as of December 31, 2015 , 2014 and 2013 .

FAIR VALUE OF FINANCIAL INSTRUM

FAIR VALUE OF FINANCIAL INSTRUMENTS	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
FAIR VALUE OF FINANCIAL INSTRUMENTS	FAIR VALUE OF FINANCIAL INSTRUMENTS The following table presents estimated fair values of the Company’s financial instruments as of December 31, 2015 and 2014 , whether or not recognized or recorded in the Consolidated Statements of Financial Condition (in thousands): December 31, 2015 December 31, 2014 Level Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value Assets: Cash and due from banks 1 $ 261,917 $ 261,917 $ 126,072 $ 126,072 Securities—trading 2,3 34,134 34,134 40,258 40,258 Securities—available-for-sale 2 1,138,573 1,138,573 411,021 411,021 Securities—held-to-maturity 3 220,666 226,627 131,258 137,608 Loans receivable held for sale 2 44,712 45,600 2,786 2,807 Loans receivable 3 7,314,504 7,084,631 3,831,034 3,722,179 FHLB stock 3 16,057 16,057 27,036 27,036 BOLI 1 156,865 156,865 63,759 63,759 Mortgage servicing rights 3 13,295 17,370 9,030 12,987 Derivatives: Interest rate swaps 2 11,984 11,984 6,290 6,290 Interest rate lock commitments 2 471 471 317 317 Liabilities: Demand, interest-bearing checking and money market 2 5,416,556 5,416,556 2,227,292 2,227,292 Regular savings 2 1,284,642 1,284,642 901,142 901,142 Certificates of deposit 2 1,353,870 1,332,825 770,516 770,516 Advances from FHLB at fair value 2 133,381 133,381 32,250 32,250 Junior subordinated debentures at fair value 3 92,480 92,480 78,001 78,001 Other borrowings 2 98,325 98,325 77,185 77,185 Derivatives: Interest rate swaps 2 11,984 11,984 6,290 6,290 Interest rate forward sales commitments 2 50 50 198 198 The Company measures and discloses 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 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. • 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 at a future date. 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: 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, 2015 and 2014 (in thousands): December 31, 2015 Level 1 Level 2 Level 3 Total Assets: Securities—trading U.S. Government and agency $ — $ 1,368 $ — $ 1,368 Municipal bonds — 341 — 341 TPS and TRUP CDOs (1) — — 18,699 18,699 Mortgage-backed securities — 13,663 — 13,663 Equity securities — 63 — 63 — 15,435 18,699 34,134 Securities—available-for-sale U.S. Government and agency — 30,231 — 30,231 Municipal bonds — 143,319 — 143,319 Corporate bonds — 15,981 — 15,981 Mortgage-backed securities — 918,259 — 918,259 Asset-backed securities — 30,685 — 30,685 Equity securities — 98 — 98 — 1,138,573 — 1,138,573 Derivatives Interest rate swaps — 11,984 — 11,984 Interest rate lock commitments — 471 — 471 $ — $ 1,166,463 $ 18,699 $ 1,185,162 Liabilities Advances from FHLB at fair value $ — $ 133,381 $ — $ 133,381 Junior subordinated debentures at fair value — — 92,480 92,480 Derivatives Interest rate swaps — 11,984 — 11,984 Interest rate forward sales commitments — 50 — 50 $ — $ 145,415 $ 92,480 $ 237,895 (1) Pooled trust preferred collateralized debt obligation securities (TRUP CDOs) 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 — 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 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 The following methods were used to estimate the fair value of each class of financial instruments: Cash and Cash Equivalents: The carrying amount of these items is a reasonable estimate of their fair value. 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 the continued limited activity in the trust preferred markets that have limited the observability of market spreads for some of the Company’s TPS and TRUP CDOs, management has classified these securities as a Level 3 fair value measure. Management periodically reviews the pricing information received from third-party pricing services and tests those prices against other sources to validate the reported fair values. Loans Held for Sale: Fair values for residential mortgage loans held for sale are determined by comparing actual loan rates to current secondary market prices for similar loans. Fair values for multifamily loans held for sale are calculated using recent sales data for comparable loans. 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. 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 impaired loans is also 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. FHLB Stock: The fair value is based upon the redemption value of the stock which equates to its carrying value. Bank-Owned Life Insurance: The fair value of BOLI policies owned is based on the various insurance contracts' cash surrender value. Mortgage Servicing Rights: Fair values are estimated based on an independent dealer analysis of discounted cash flows. The evaluation utilizes assumptions market participants would use in determining fair value including prepayment speeds, delinquency and foreclosure rates, the discount rate, servicing costs, and the timing of cash flows. The mortgage servicing portfolio is stratified by loan type and fair value estimates are adjusted up or down based on the serviced loan interest rates versus current rates on new loan originations since the most recent independent analysis. Deposits: The carrying amount of deposits with no stated maturity, such as savings and checking accounts, is a reasonable estimate of their fair value. 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. FHLB Advances: Fair valuations for Banner’s FHLB advances are estimated using fair market values provided by the lender, the FHLB of Des Moines. The FHLB of Des Moines prices advances by discounting the future contractual cash flows for individual advances, using its current cost of funds curve to provide the discount rate. Junior Subordinated Debentures: The fair value of junior subordinated debentures is estimated using an income approach technique. The significant inputs included in the estimation of fair value are the credit risk adjusted spread and three month LIBOR. The credit risk adjusted spread represents the nonperformance risk of the liability. The Company utilizes an external valuation firm to validate the reasonableness of the credit risk adjusted spread used to determine the fair value. The junior subordinated debentures are carried at fair value which represents the estimated amount that would be paid to transfer these liabilities in an orderly transaction amongst market participants. Due to credit concerns in the capital markets and inactivity in the trust preferred markets that have limited the observability of market spreads, management has classified this as a Level 3 fair value measure. Other Borrowings: Other borrowings include securities sold under agreements to repurchase and occasionally federal funds purchased and their carrying amount is considered a reasonable approximation of their fair value. Derivatives: 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 these instruments, 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. Off-Balance Sheet Items: Off-balance sheet financial instruments include unfunded commitments to extend credit, including standby letters of credit, and commitments to purchase investment securities. The fair value of these instruments is not considered to be material. Limitations: The fair value estimates presented herein are based on pertinent information available to management as of December 31, 2015 and 2014 . 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. 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, 2015 and 2014 : December 31 2015 2014 Financial Instruments Valuation Technique Unobservable Inputs Weighted Average Rate Weighted Average Rate TPS securities Discounted cash flows Discount rate 5.61 % 5.26 % TRUP CDOs Discounted cash flows Discount rate n/a 3.96 Junior subordinated debentures Discounted cash flows Discount rate 5.61 5.26 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 Securities 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, 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, 2015, or the passage of time, will result in negative fair value adjustments. At December 31, 2015, the discount rate utilized was based on a credit spread of 500 basis points and three month LIBOR of 62 basis points. 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, 2015 and 2014 (in thousands): Year Ended December 31, 2015 Level 3 Fair Value Inputs TPS and TRUP CDOs Borrowings— Junior Subordinated Debentures Beginning balance at December 31, 2014 $ 19,119 $ 78,001 Total gains or losses recognized Assets gains 537 — Liabilities losses — 2,714 Purchases, issuances and settlements, net 5,697 11,765 Paydowns and maturities (6,654 ) — Transfers in and/or out of Level 3 — — Ending balance at December 31, 2015 $ 18,699 $ 92,480 Year Ended December 31, 2014 Level 3 Fair Value Inputs TPS and TRUP CDOs Borrowings— Junior Subordinated Debentures Beginning balance at December 31, 2013 $ 35,140 $ 73,928 Total gains or losses recognized Assets gains 5,481 — Liabilities 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 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 non-interest income. Items Measured at Fair Value on a Non-recurring 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 of the fair value measurements for those assets at December 31, 2015 and 2014 (in thousands): At or For the Year Ended December 31, 2015 Level 1 Level 2 Level 3 Total Impaired loans $ — $ — $ 2,372 $ 2,372 REO — — 11,627 11,627 At or For the Year Ended December 31, 2014 Level 1 Level 2 Level 3 Total Impaired loans $ — $ — $ 4,725 $ 4,725 REO — — 3,352 3,352 The following table presents the losses resulting from non-recurring fair value adjustments for the years ended December 31, 2015 and 2014 (in thousands): For the twelve months ended December 31, 2015 2014 Impaired loans $ (110 ) $ (512 ) REO (231 ) (453 ) Total loss from nonrecurring measurements $ (341 ) $ (965 ) Impaired loans : 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. Impaired loans are periodically evaluated to determine if valuation adjustments, or partial write-downs, should be recorded. The need for valuation adjustments arises when observable market prices or current appraised values of collateral indicate a shortfall in collateral value 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 losses or charges off the impaired amount. These valuation adjustments are considered non-recurring fair value adjustments. The remaining impaired loans are evaluated for reserve needs in homogenous pools within the Company’s methodology for assessing the adequacy of the allowance for loan losses. REO : The Company records REO (acquired through a lending relationship) at fair value on a non-recurring basis. Fair value adjustments on REO are based on updated real estate appraisals which are based on current market conditions. All REO properties are recorded at the estimated fair value of the real estate, less expected selling costs. 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.

BANNER CORPORATION (PARENT COMP

BANNER CORPORATION (PARENT COMPANY ONLY)	12 Months Ended
	Dec. 31, 2015
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 December 31 2015 2014 ASSETS Cash $ 58,232 $ 52,124 Investment in trust equities 4,212 3,716 Investment in subsidiaries 1,319,348 610,732 Other assets 21,134 8,279 $ 1,402,926 $ 674,851 LIABILITIES AND SHAREHOLDERS’ EQUITY Miscellaneous liabilities $ 7,846 $ 2,446 Deferred tax liability 2,541 11,516 Junior subordinated debentures at fair value 92,480 78,001 Shareholders’ equity 1,300,059 582,888 $ 1,402,926 $ 674,851 Statements of Operations Years Ended December 31 2015 2014 2013 INTEREST INCOME: Interest-bearing deposits $ 122 $ 96 $ 82 OTHER INCOME (EXPENSE): Dividend income from subsidiaries 170,260 26,027 24,725 Equity in undistributed (distributions in excess of) income of subsidiaries (116,120 ) 33,612 23,653 Other income 69 67 3,016 Net change in valuation of financial instruments carried at fair value (2,714 ) (4,073 ) (865 ) Interest on other borrowings (3,247 ) (2,914 ) (2,968 ) Other expenses (7,175 ) (2,519 ) (2,794 ) Net income before taxes 41,195 50,296 44,849 BENEFIT FROM INCOME TAXES (4,027 ) (3,774 ) (1,365 ) NET INCOME $ 45,222 $ 54,070 $ 46,214 Statements of Cash Flows Years Ended December 31 2015 2014 2013 OPERATING ACTIVITIES: Net income $ 45,222 $ 54,070 $ 46,214 Adjustments to reconcile net income to net cash provided by operating activities: Distributions in excess of (Equity in undistributed) income of subsidiaries 116,120 (33,612 ) (23,653 ) Increase (decrease) in deferred taxes (1,398 ) (1,444 ) 17 Net change in valuation of financial instruments carried at fair value 2,714 4,073 865 Increase in other assets (10,655 ) (3,822 ) (4,655 ) Increase (decrease) in other liabilities 3,919 222 (1,921 ) Net cash provided from operating activities 155,922 19,487 16,867 INVESTING ACTIVITIES: Funds transferred to deferred compensation trust (26 ) (26 ) (27 ) Acquisitions (132,652 ) — — Net cash used by investing activities (132,678 ) (26 ) (27 ) FINANCING ACTIVITIES: Issuance of stock for shareholder reinvestment program 34 127 72 Cash dividends paid (17,170 ) (13,462 ) (7,798 ) Net cash used by financing activities (17,136 ) (13,335 ) (7,726 ) NET CHANGE IN CASH 6,108 6,126 9,114 CASH, BEGINNING OF PERIOD 52,124 45,998 36,884 CASH, END OF PERIOD $ 58,232 $ 52,124 $ 45,998

STOCK REPURCHASES

STOCK REPURCHASES	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
STOCK REPURCHASE	STOCK REPURCHASES 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 shares of its common stock during the years ended December 31, 2015 , 2014 or 2013 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. The ESOP terminated during the year ended December 31, 2014.

CALCULATION OF EARNINGS PER COM

CALCULATION OF EARNINGS PER COMMON SHARE	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
CALCULATION OF EARNINGS PER COMMON SHARE	CALCULATION OF EARNINGS PER COMMON SHARE The following tables show the calculation of earnings per common share (in thousands, except per share data): Years Ended December 31 2015 2014 2013 Net income $ 45,222 $ 54,070 $ 46,214 Weighted average number of common shares outstanding Basic 23,801,373 19,359,409 19,361,411 Diluted 23,866,621 19,402,656 19,397,360 Earnings per common share Basic $ 1.90 $ 2.79 $ 2.39 Diluted $ 1.89 $ 2.79 $ 2.38 At December 31, 2015 , there were 231,562 issued but unvested restricted stock shares and units that were included in the computation of diluted earnings per share. Options to purchase an additional 5,000 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 DA

SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED)	12 Months Ended
	Dec. 31, 2015
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, 2015 , 2014 and 2013 were as follows (dollars in thousands except for per share data): Year Ended December 31, 2015 First Quarter Second Quarter Third Quarter Fourth Quarter Interest income $ 49,069 $ 54,076 $ 54,793 $ 96,495 Interest expense 2,533 2,619 2,605 4,396 Net interest income before provision for loan losses 46,536 51,457 52,188 92,099 Provision for loan losses — — — — Net interest income 46,536 51,457 52,188 92,099 Non-interest income 13,696 16,141 14,098 18,356 Non-interest expense 41,914 47,734 46,697 100,254 Income before provision for income taxes 18,318 19,864 19,589 10,201 Provision for income taxes 6,184 6,615 6,642 3,308 Net income $ 12,134 $ 13,249 $ 12,947 $ 6,893 Basic earnings per share $ 0.61 $ 0.64 $ 0.62 $ 0.20 Diluted earnings per share 0.61 0.64 0.62 0.20 Dividends declared 0.18 0.18 0.18 0.18 Year Ended December 31, 2014 First Quarter Second Quarter Third Quarter Fourth 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 Non-interest income 9,032 20,310 13,536 12,113 Non-interest expense 35,581 38,435 38,495 41,230 Income before provision for income taxes 15,790 25,683 22,105 17,544 Provision for income taxes 5,241 8,696 7,284 5,831 Net income $ 10,549 $ 16,987 $ 14,821 $ 11,713 Basic earnings per share $ 0.55 $ 0.88 $ 0.76 $ 0.60 Diluted earnings per share 0.54 0.88 0.76 0.60 Dividends declared 0.18 0.18 0.18 0.18 Year Ended December 31, 2013 First Quarter Second Quarter Third Quarter Fourth Quarter Interest income $ 44,508 $ 45,571 $ 45,037 $ 44,596 Interest expense 3,540 3,323 3,144 2,989 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 Non-interest income 10,088 10,953 10,592 13,029 Non-interest expense 34,099 35,457 34,490 36,929 Income (loss) before provision for income taxes 16,957 17,744 17,995 17,707 Provision (benefit) for income taxes 5,373 6,076 6,459 6,281 Net income $ 11,584 $ 11,668 $ 11,536 $ 11,426 Basic earnings per share $ 0.60 $ 0.60 $ 0.60 $ 0.59 Diluted earnings per share 0.60 0.60 0.59 0.59 Dividends declared 0.12 0.12 0.15 0.15

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	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, 2015 December 31, 2014 Commitments to extend credit $ 2,132,996 $ 1,166,165 Standby letters of credit and financial guarantees 22,315 9,934 Commitments to originate loans 32,908 20,988 Derivatives also included in Note 24: Commitments to originate loans held for sale 76,146 29,851 Commitments to sell loans secured by one- to four-family residential properties 37,545 8,714 Commitments to sell securities related to mortgage banking activities 41,500 25,000 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. The Company's reserve for unfunded loan commitments was $3.9 million and $732,000 , at December 31, 2015 and 2014 , respectively. 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. The Company enters 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 2015 or 2014 . 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.” 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, 2015 . 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.

DERIVATIVES AND HEDGING DERIVAT

DERIVATIVES AND HEDGING DERIVATIVES AND HEDGING	12 Months Ended
	Dec. 31, 2015
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. Under a prior program, customers received fixed interest rate commercial loans and the Banner Bank subsequently hedged that fixed rate loan by entering into an interest rate swap with a dealer counterparty. Banner 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, 2015 and December 31, 2014 , 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, 2015 December 31, 2014 December 31, 2015 December 31, 2014 Notional/ Contract Amount Fair Value (1) Notional/ Contract Amount Fair Value (1) Notional/ Contract Amount Fair Value (2) Notional/ Contract Amount Fair Value (2) Interest rate swaps $ 6,734 $ 938 $ 7,089 $ 1,165 $ 6,734 $ 938 $ 7,089 $ 1,165 (1) Included in Loans Receivable on the Consolidated Statements of Financial Condition. (2) Included in Other Liabilities on the Consolidated Statements of Financial Condition. Derivatives Not Designated in Hedge Relationships Interest Rate Swaps: Banner Bank uses an interest rate swap program for commercial loan customers, that 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. These swaps do not qualify as designated hedges; therefore, each swap is accounted for as a free standing derivative. Through the acquisition of AmericanWest, Banner Bank assumed a risk participation agreement. Under the risk participation agreement, Banner Bank guarantees the financial performance of a borrower on the participated portion of a interest rate swap on a loan. 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, 2015 and December 31, 2014 , 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, 2015 December 31, 2014 December 31, 2015 December 31, 2014 Notional/ Contract Amount Fair Value (1) Notional/ Contract Amount Fair Value (1) Notional/ Contract Amount Fair Value (2) Notional/ Contract Amount Fair Value (2) Interest rate swaps $ 293,937 $ 11,046 $ 134,512 $ 5,125 $ 293,937 $ 11,046 $ 134,512 $ 5,125 Risk participation agreement — — — — 7,672 36 — — Mortgage loan commitments 76,146 428 29,311 317 — — — — Forward sales contracts 41,500 43 — — 32,763 50 33,174 198 $ 411,583 $ 11,517 $ 163,823 $ 5,442 $ 334,372 $ 11,132 $ 167,686 $ 5,323 (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 $327,000 at December 31, 2015 and $558,000 at December 31, 2014 ), 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, 2015 and 2014 were as follows (in thousands): For the Year Ended December 31 Location on Income Statement 2015 2014 Mortgage loan commitments Mortgage banking operations $ 100 $ 221 Forward sales contracts Mortgage banking operations 141 (188 ) $ 241 $ 33 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, 2015 or December 31, 2014 , it could have been required to settle its obligations under the agreements at the termination value. As of December 31, 2015 and 2014 , the termination value of derivatives in a net liability position related to these agreements was $12.0 million and $6.3 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 $20.8 million and $11.1 million as of December 31, 2015 and 2014 , 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, 2015 and December 31, 2014 (in thousands): December 31, 2015 Gross Amounts of Financial Instruments Not Offset in the Statement of Financial Condition Gross Amounts Recognized Amounts offset in the Statement of Financial Condition Net Amounts in the Statement of Financial Condition Netting Adjustment Per Applicable Master Netting Agreements Fair Value of Financial Collateral in the Statement of Financial Condition Net Amount Derivative assets Interest rate swaps $ 11,984 $ — $ 11,984 $ — $ — $ 11,984 $ 11,984 $ — $ 11,984 $ — $ — $ 11,984 Derivative liabilities Interest rate swaps $ 11,984 $ — $ 11,984 $ — $ (11,984 ) $ — $ 11,984 $ — $ 11,984 $ — $ (11,984 ) $ — December 31, 2014 Gross Amounts of Financial Instruments Not Offset in the Statement of Financial Condition Gross Amounts Recognized Amounts offset in the Statement of Financial Condition Net Amounts in the Statement of Financial Condition Netting Adjustment Per Applicable Master Netting Agreements Fair Value of Financial Collateral in the Statement of Financial Condition Net Amount 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

BASIS OF PRESENTATION AND SUM33

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Goodwill and Intangible Assets, Goodwill, Policy	Goodwill: Goodwill represents the excess of the purchase consideration over the fair value of the assets acquired, net of the fair values of liabilities assumed in a business combination and is not amortized but is reviewed annually, or more frequently as current circumstances and conditions warrant, for impairment. An assessment of qualitative factors is completed to determine if it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If the qualitative analysis concludes that further analysis is required, then a quantitative impairment test would be completed. The quantitative goodwill impairment test is a two-step process. The first step compares the reporting unit's estimated fair values, including goodwill, to its carrying amount. If the carrying amount exceeds its fair value, then goodwill impairment may be indicated. The second step allocates the reporting units fair value to its assets and liabilities. If the unallocated fair value does not exceed the carrying amount of goodwill then an impairment loss would be recognized as a charge to earnings.
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. The consolidated financial statements of the Company have been prepared in accordance with generally accepted accounting principles in the United States (GAAP) and under the rules and regulations of the U.S. Securities and Exchange Commission (the SEC).
Subsequent Events	Subsequent Events: The Company has evaluated events and transactions subsequent to December 31, 2015 for potential recognition or disclosure .
Cash and Cash Equivalents, Policy	Cash and Cash Equivalents: Cash and cash equivalents include cash and due from banks and temporary investments which are federal funds sold and interest bearing balances due from other banks. Cash and cash equivalents generally have maturities of three months or less at the date of purchase.
Business Combinations	Business Combinations: Business combinations are accounted for using the acquisition method of accounting and, accordingly, assets acquired and liabilities assumed, both tangible and intangible, and consideration exchanged are recorded at acquisition date fair values. The excess purchase consideration over fair value of net assets acquired is recorded as goodwill. In the event that the fair value of net assets acquired exceeds the purchase price, including fair value of liabilities assumed, a bargain purchase gain is recorded on that acquisition. Expenses incurred in connection with a business combination are expensed as incurred. Changes in deferred tax asset valuation allowances related to acquired tax uncertainties are recognized in net income after the measurement period.
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, changes in shareholders’ equity and cash flows reflect all adjustments (which include reclassification and normal recurring adjustments) that are necessary for a fair presentation in conformity with 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 (vii) the valuation of assets and liabilities acquired in business combinations. These policies and judgments, estimates and assumptions are described in greater detail in subsequent Notes to the Consolidated Financial Statements. 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 shareholders’ 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 18 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, 2015 , the Banks had $16.1 million in FHLB stock, compared to $27.0 million at December 31, 2014 . 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 Company has determined there is not any impairment on the FHLB stock investment as of December 31, 2015 .
Loans Receivable	Loans Receivable: The Banks originate residential one- to four-family and multifamily mortgage loans for both portfolio investment and sale in the secondary market. The Banks also originate construction and land development, commercial 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 appropriately reported as TDRs when the Banks grant 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.
Acquired Loans Policy	Acquired Loans: Purchased loans, including loans acquired in business combinations, are recorded at their fair value at the acquisition date. Credit discounts are included in the determination of fair value; therefore, an allowance for loan and lease losses is not recorded at the acquisition date. Acquired loans are evaluated upon acquisition and classified as either purchased credit-impaired or purchased non-credit-impaired. Purchased credit-impaired (PCI) loans reflect credit deterioration since origination such that it is probable at acquisition that the Company will be unable to collect all contractually required payments. The excess of the cash flows expected to be collected over a PCI pool's carrying value is considered to be the accretable yield and is recognized as interest income over the estimated life of the pool using the effective yield method. The excess of the undiscounted contractual balances due over the cash flows expected to be collected is considered to be the nonaccretable difference. The nonaccretable difference represents our estimate of the credit losses expected to occur and was considered in determining the fair value of the loans as of the acquisition date. Subsequent to the acquisition date, any increases in expected cash flows over those expected at purchase date in excess of fair value are adjusted through a change to the accretable yield on a prospective basis. Any subsequent decreases in expected cash flows attributable to credit deterioration are recognized by recording a provision for loan losses. For purchased non-credit-impaired loans, the difference between the fair value and unpaid principal balance of the loan at the acquisition date is amortized or accreted to interest income over the life of the loans. Any subsequent deterioration in credit quality is recognized by recording a provision for loan losses.
Income Recognition on Nonaccrual and Impaired Loans	Income Recognition on Nonaccrual and Impaired Loans and Securities: 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 or principal 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 GAAP. 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 loan losses 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 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 for loan losses. 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 for loan losses 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 if the loan is collateral dependent, at the fair value of collateral less selling costs. 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 for loan losses 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 loan 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 for loan losses 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 initially recorded at the estimated fair value of the property, less expected selling costs. 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: Property and equipment is carried at cost less accumulated depreciation. The provision for depreciation is based upon the straight-line method applied to individual assets and groups of assets acquired in the same year over the lesser of their estimated useful lives or the related lease terms of the assets: 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 ten 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 values are estimated based on an independent dealer analysis of discounted cash flows. 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 Statements 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.
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.” Banner Bank is a party to $12.0 million in notional amounts of interest rate swaps at December 31, 2015 . 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, Banner Bank uses an interest rate swap program for commercial loan customers that provides the client with a variable rate loan and enters into an interest rate swap 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. At December 31, 2015 , Banner Bank had $282.0 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 are reflected in other assets or other liabilities as appropriate. 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 24 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, 2015 , 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 income tax expense. The amount of interest and penalties accrued for the years ended December 31, 2015 and 2014 is immaterial. The Company files consolidated income tax returns in Oregon, California, Utah and Idaho and for federal purposes. The Company has tax years 2011–2014 open for tax examination under the statute of limitation provisions of the Internal Revenue Code of 1986 (Code).
Share-Based Compensation	Stock-Based Compensation: The Company has adopted the fair value recognition method for recognizing stock-based 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. Stock Options: Stock option grant stock-based compensation costs under the Company's stock options plans 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 U.S. 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.
Earnings Per Share, Policy	Earnings Per Share: Earnings per common share is computed under the two-class method. Pursuant to the two-class method, nonvested stock-based payment awards that contain nonforfeitable rights to dividends or dividend equivalents are participating securities and are included in the computation of EPS pursuant. The two-class method is an earnings allocation formula that determines earnings per share for each class of common stock and participating security according to dividends declared (or accumulated) and participation rights in undistributed earnings.
Comprehensive Income	Comprehensive Income: 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.
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 shareholders. 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 or net income as previously presented and the effect of these reclassifications is considered immaterial. For the impacts of the retrospective adoption of ASU No. 2014-01, Accounting for Investments in Qualified Affordable Housing Projects, see Note 2.

BASIS OF PRESENTATION AND SUM34

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2015
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 over the lesser of their estimated useful lives or the related lease terms of the assets: Buildings and leased improvements 10–30 years Furniture and equipment 3 – 10 years

BUSINESS COMBINATIONS BUSINES35

BUSINESS COMBINATIONS BUSINESS COMBINATIONS (Tables)	12 Months Ended
	Dec. 31, 2015
Business Acquisition [Line Items]
Business Acquisition, Pro Forma Information	As a result, actual amounts would have differed from the unaudited pro forma information presented (in thousands except per share amounts): Pro Forma Years Ended December 31 2015 2014 Total revenues (net interest income plus non-interest income) $ 455,427 $ 430,984 Net income $ 86,255 $ 87,031 Earnings per share - basic $ 2.56 $ 2.67 Earnings per share - diluted $ 2.55 $ 2.67 As a result, actual amounts would have differed from the unaudited pro forma information presented (in thousands except per share amounts): Pro Forma Years Ended December 31 2015 2014 Total revenues (net interest income plus non-interest income) $ 308,153 $ 254,212 Net income $ 44,484 $ 58,703 Earnings per share - basic $ 1.85 $ 2.84 Earnings per share - diluted $ 1.85 $ 2.83
Six Oregon Branches [Member]
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): Branch Purchase June 20, 2014 Total consideration $ — Fair value of assets acquired: Cash and cash equivalents $ 127,557 Loans receivable (contractual amount of $88.3 million) 87,923 Property and equipment 3,079 CDI 2,372 Other assets 275 Total assets acquired 221,206 Fair value of liabilities assumed: Deposits 212,085 Other liabilities 42 Total liabilities assumed 212,127 Net assets acquired 9,079 Acquisition bargain purchase gain $ (9,079 )
Siuslaw Financial Group, Inc [Member]
Business Acquisition [Line Items]
Schedule of Components of Business Acquisition	The following table presents a summary of the consideration paid and the estimated fair values as of the acquisition date for each major class of assets acquired and liabilities assumed (in thousands): Siuslaw March 6, 2015 Consideration to Siuslaw shareholders: Cash paid $ 5,806 Fair value of common shares issued 58,100 Total consideration 63,906 Fair value of assets acquired: Cash and cash equivalents $ 84,405 Securities—available-for-sale 12,865 Loans receivable (contractual amount of $252.2 million) 247,098 REO, held for sale 2,525 Property and equipment 8,127 CDI 3,895 Other assets 10,848 Total assets acquired 369,763 Fair value of liabilities assumed: Deposits 316,406 Junior subordinated debentures 5,959 Other liabilities 5,183 Total liabilities assumed 327,548 Net assets acquired $ 42,215 Goodwill 21,691
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period	The following table presents the acquired PCI loans as of the acquisition date (in thousands): Siuslaw March 6, 2015 Acquired PCI loans: Contractually required principal and interest payments $ 11,134 Nonaccretable difference (3,238 ) Cash flows expected to be collected 7,896 Accretable yield (2,239 ) Fair value of PCI loans $ 5,657
Schedule of Acquisition Related Costs	The following tables present the key components of acquisition-related costs in connection with the Branch purchase, the acquisition of Siuslaw and the acquisition of Starbuck, including AmericanWest, for the years ended December 31, 2015 , 2014 and 2013 (in thousands): Years Ended December 31 2015 2014 2013 Acquisition-related costs recognized in non-interest expense: Personnel severance/retention fees $ 6,577 $ — $ — Non-capitalized equipment and repairs 1,031 105 — Client communications 527 327 — Information/computer data services 2,875 334 — Payment and processing expenses 28 185 — Professional services 11,169 2,953 550 Miscellaneous 3,903 421 — $ 26,110 $ 4,325 $ 550 The Branch purchase $ — $ 1,784 $ 550 Siuslaw 2,000 748 — Starbuck 24,110 1,793 — $ 26,110 $ 4,325 $ 550
Starbuck Bancshares, Inc [Member]
Business Acquisition [Line Items]
Schedule of Components of Business Acquisition	The following table presents a summary of the consideration paid and the estimated fair values as of the acquisition date for each major class of assets acquired and liabilities assumed (in thousands): Starbuck October 1, 2015 Consideration to Starbuck equityholders: Cash paid $ 130,000 Fair value of common shares issued 630,674 Total consideration 760,674 Fair value of assets acquired: Cash and cash equivalents $ 95,821 Securities 1,037,238 Loans receivable (contractual amount of $3.04 billion) 2,997,640 REO, held for sale 5,706 Property and equipment 66,549 CDI 33,500 Deferred tax asset 107,847 Other assets 113,173 Total assets acquired 4,457,474 Fair value of liabilities assumed: Deposits 3,638,596 FHLB advances 221,442 Junior subordinated debentures 5,806 Other liabilities 57,003 Total liabilities assumed 3,922,847 Net assets acquired 534,627 Goodwill $ 226,047
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period	The following table presents the acquired PCI loans as of the acquisition date (in thousands): Starbuck October 1, 2015 Acquired PCI loans: Contractually required principal and interest payments $ 98,746 Nonaccretable difference (26,162 ) Cash flows expected to be collected 72,584 Accretable yield (11,071 ) Fair value of PCI loans $ 61,513

SECURITIES (Tables)

SECURITIES (Tables)	12 Months Ended
	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Schedule of Securities	The amortized cost, gross unrealized losses and gains and estimated fair value of securities at December 31, 2015 and 2014 are summarized as follows (in thousands): December 31, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Trading: U.S. Government and agency obligations $ 1,230 $ 1,368 Municipal bonds 332 341 Corporate bonds 25,063 18,699 Mortgage-backed or related securities 12,705 13,663 Equity securities 14 63 $ 39,344 $ 34,134 Available-for-Sale: U.S. Government and agency obligations $ 30,211 $ 213 $ (193 ) $ 30,231 Municipal bonds 142,898 853 (432 ) 143,319 Corporate bonds 15,937 56 (12 ) 15,981 Mortgage-backed or related securities 919,318 4,056 (5,115 ) 918,259 Asset-backed securities 31,288 — (603 ) 30,685 Equity securities 88 10 — 98 $ 1,139,740 $ 5,188 $ (6,355 ) $ 1,138,573 Held-to-Maturity: U.S. Government and agency obligations $ 1,106 $ 5 $ — $ 1,111 Municipal bonds: 162,778 6,219 (191 ) 168,806 Corporate bonds 4,273 — — 4,273 Mortgage-backed or related securities 52,509 253 (325 ) 52,437 $ 220,666 $ 6,477 $ (516 ) $ 226,627 December 31, 2014 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Trading: U.S. Government and agency obligations $ 1,340 $ 1,505 Municipal bonds 1,405 1,440 Corporate bonds 27,995 19,118 Mortgage-backed or related securities 16,726 18,136 Equity securities 14 59 $ 47,480 $ 40,258 Available-for-Sale: U.S. Government and agency obligations $ 29,973 $ 8 $ (211 ) $ 29,770 Municipal bonds 49,959 190 (121 ) 50,028 Corporate bonds 5,000 18 — 5,018 Mortgage-backed or related securities 300,979 1,429 (1,598 ) 300,810 Asset-backed securities 25,513 167 (285 ) 25,395 $ 411,424 $ 1,812 $ (2,215 ) $ 411,021 Held-to-Maturity: U.S. Government and agency obligations $ 2,146 $ — $ (19 ) $ 2,127 Municipal bonds: 119,951 6,319 (48 ) 126,222 Corporate bonds 1,800 — — 1,800 Mortgage-backed or related securities 7,361 105 (7 ) 7,459 $ 131,258 $ 6,424 $ (74 ) $ 137,608
Schedule of Securities with Continuous Loss Position	At December 31, 2015 and 2014 , the gross unrealized losses and the fair value for securities available-for-sale and held-to-maturity aggregated by the length of time that individual securities have been in a continuous unrealized loss position was as follows (in thousands): December 31, 2015 Less Than 12 Months 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Available-for-Sale: U.S. Government and agency obligations $ 8,707 $ (97 ) $ 10,489 $ (96 ) $ 19,196 $ (193 ) Municipal bonds 69,848 (426 ) 905 (6 ) 70,753 (432 ) Corporate bonds 5,153 (12 ) — — 5,153 (12 ) Mortgage-backed or related securities 533,143 (4,380 ) 68,562 (735 ) 601,705 (5,115 ) Asset-backed securities 20,893 (355 ) 9,792 (248 ) 30,685 (603 ) $ 637,744 $ (5,270 ) $ 89,748 $ (1,085 ) $ 727,492 $ (6,355 ) Held-to-Maturity: Municipal bonds $ 28,545 $ (188 ) $ 254 $ (3 ) $ 28,799 $ (191 ) Corporate bonds — — — — — — Mortgage-backed or related securities 34,493 (323 ) 255 (2 ) 34,748 (325 ) $ 63,038 $ (511 ) $ 509 $ (5 ) $ 63,547 $ (516 ) December 31, 2014 Less Than 12 Months 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Available-for-Sale: U.S. Government and agency obligations $ 15,983 $ (58 ) $ 9,847 $ (153 ) $ 25,830 $ (211 ) Municipal bonds 16,322 (61 ) 7,129 (60 ) 23,451 (121 ) Mortgage-backed or related securities 91,046 (236 ) 107,266 (1,362 ) 198,312 (1,598 ) Asset-backed securities — — 9,765 (285 ) 9,765 (285 ) $ 123,351 $ (355 ) $ 134,007 $ (1,860 ) $ 257,358 $ (2,215 ) Held-to-Maturity: U.S. Government and agency obligations $ — $ — $ 1,127 $ (19 ) $ 1,127 $ (19 ) Municipal bonds 9,821 (44 ) 592 (4 ) 10,413 (48 ) Mortgage-backed or related securities 1,018 (7 ) — — 1,018 (7 ) $ 10,839 $ (51 ) $ 1,719 $ (23 ) $ 12,558 $ (74 )
Schedule of Securities by Contractual Maturity Date	The amortized cost and estimated fair value of securities at December 31, 2015 , 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, 2015 Trading Available-for-Sale Held-to-Maturity Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Maturing in one year or less $ — $ — $ 12,522 $ 12,477 $ 4,986 $ 5,035 Maturing after one year through five years 8,790 9,361 278,205 277,056 13,707 13,810 Maturing after five years through ten years 3,480 3,823 185,919 184,948 83,478 84,158 Maturing after ten years through twenty years 1,997 2,188 338,069 338,362 99,614 104,460 Maturing after twenty years 25,063 18,699 324,937 325,632 18,881 19,164 39,330 34,071 1,139,652 1,138,475 220,666 226,627 Equity securities 14 63 88 98 $ 39,344 $ 34,134 $ 1,139,740 $ 1,138,573 $ 220,666 $ 226,627
Schedule of Pledged Securities	The following table presents, as of December 31, 2015 , 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 $ 204,894 $ 201,149 $ 210,422 Interest rate swap counterparties 13,687 13,284 13,687 Repurchase transaction accounts 110,140 109,956 110,146 Other 1,970 1,895 1,970 Total pledged securities $ 330,691 $ 326,284 $ 336,225

LOANS RECEIVABLE AND THE ALLO37

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Tables)	12 Months Ended
	Dec. 31, 2015
Receivables [Abstract]
Impaired loans excluding purchased credit impaired loans [Table Text Block]	The following tables provide additional information on impaired loans, excluding purchased credit impaired loans, with and without specific allowance reserves at December 31, 2015 and 2014 . Recorded investment includes the unpaid principal balance or the carrying amount of loans less charge-offs and net deferred loan fees (in thousands): December 31, 2015 Unpaid Principal Balance Recorded Investment Related Allowance Without Allowance (1) With Allowance (2) Commercial real estate: Owner-occupied $ 1,465 $ — $ 1,416 $ 70 Investment properties 8,740 2,503 5,846 602 Multifamily real estate 359 — 357 71 Commercial construction 1,141 1,069 — — One- to four-family construction 1,741 — 1,741 161 Land and land development: Residential 3,540 750 1,634 444 Commercial 1,628 1,027 — Commercial business 2,266 538 1,184 150 Agricultural business/farmland 1,309 544 697 43 One- to four-family residential 17,897 2,206 14,418 736 Consumer: Consumer secured by one- to four-family 776 — 716 23 Consumer—other 433 — 351 7 $ 41,295 $ 8,637 $ 28,360 $ 2,307 December 31, 2014 Unpaid Principal Balance Recorded Investment Related Allowance Without Allowance (1) With Allowance (2) Commercial real estate: Owner-occupied $ 1,598 $ 966 $ 582 $ 24 Investment properties 6,458 30 6,023 729 Multifamily real estate 786 — 786 86 One- to four-family construction 3,923 — 3,923 640 Land and land development: Residential 3,710 1,275 1,280 346 Commercial business 1,502 — 1,276 128 Agricultural business/farmland 1,597 744 854 26 One- to four-family residential 27,855 1,865 24,529 1,032 Consumer: Consumer secured by one- to four-family 1,256 73 1,077 75 Consumer—other 634 138 470 6 $ 49,319 $ 5,091 $ 40,800 $ 3,092 (1) Loans without an allowance reserve have been individually evaluated for impairment and that evaluation concluded that no reserve was needed. (2) Includes general reserves for loans evaluated in pools of homogeneous loans and loans with a specific reserve allowance. 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 less costs to sell to establish realizable value.
Allowance for Credit Losses on Financing Receivables [Table Text Block]	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, 2015 (in thousands): For the Year Ended December 31, 2015 Commercial Real Estate Multifamily Real Estate Construction and Land Commercial Business Agricultural Business One- to Four-Family Residential Consumer Unallocated Total Allowance for loan losses: Beginning balance $ 18,784 $ 4,562 $ 25,545 $ 12,043 $ 3,821 $ 5,447 $ 483 $ 5,222 $ 75,907 Provision for loan losses 1,177 (480 ) 666 1,611 (878 ) (1,068 ) 1,363 (2,391 ) — Recoveries 819 113 1,811 948 1,927 772 570 — 6,960 Charge-offs (64 ) — (891 ) (746 ) (1,225 ) (419 ) (1,514 ) — (4,859 ) Ending balance $ 20,716 $ 4,195 $ 27,131 $ 13,856 $ 3,645 $ 4,732 $ 902 $ 2,831 $ 78,008 December 31, 2015 Commercial Real Estate Multifamily Construction and Land Commercial Business Agricultural Business One- to Four-Family Residential Consumer Unallocated Total Allowance individually evaluated for impairment $ 605 $ 71 $ 418 $ 69 $ — $ 728 $ 29 $ — $ 1,920 Allowance collectively evaluated for impairment 20,111 4,124 26,713 13,732 3,645 4,004 873 2,831 76,033 Allowance for purchased credit-impaired loans — — — 55 — — — — 55 Total allowance for loan losses $ 20,716 $ 4,195 $ 27,131 $ 13,856 $ 3,645 $ 4,732 $ 902 $ 2,831 $ 78,008 December 31, 2015 Commercial Real Estate Multifamily Construction and Land Commercial Business Agricultural Business One- to Four-Family Residential Consumer Unallocated Total Loan balances: Loans individually evaluated for impairment $ 8,519 $ 357 $ 4,669 $ 2,223 $ 544 $ 12,185 $ 319 $ — $ 28,816 Loans collectively evaluated for impairment 3,043,656 470,625 564,051 1,198,419 374,458 939,382 636,497 — 7,227,088 Purchased credit-impaired loans 40,985 1,994 5,650 7,302 1,529 1,066 74 — 58,600 Total loans $ 3,093,160 $ 472,976 $ 574,370 $ 1,207,944 $ 376,531 $ 952,633 $ 636,890 $ — $ 7,314,504 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 Real Estate Multifamily Construction and Land Commercial Business Agricultural Business One- to Four-Family Residential Consumer Unallocated Total 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 Real Estate Multifamily Construction and Land Commercial Business Agricultural Business One- to Four-Family Residential Consumer Unallocated Total 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 Real Estate Multifamily Construction and Land Commercial Business Agricultural Business One- to Four-Family Residential Consumer Unallocated Total Loan balances: Loans individually evaluated for impairment $ 7,171 $ 786 $ 6,477 $ 739 $ 744 $ 17,848 $ 681 $ — $ 34,446 Loans collectively evaluated for impairment 1,396,554 166,738 404,529 723,225 237,755 519,260 348,527 — 3,796,588 Total loans $ 1,403,725 $ 167,524 $ 411,006 $ 723,964 $ 238,499 $ 537,108 $ 349,208 $ — $ 3,831,034
Past Due Financing Receivables [Table Text Block]	The following tables provide additional detail on the age analysis of Banner’s past due loans as of December 31, 2015 and 2014 (in thousands): December 31, 2015 30 – 59 Days Past Due 60 – 89 Days Past Due 90 Days or More Past Due Total Past Due Purchased Credit-Impaired Current Total Loans Loans 90 Days or More Past Due and Accruing Non-accrual Commercial real estate: Owner-occupied $ 3,981 $ 139 $ 885 $ 5,005 $ 24,261 $ 1,298,541 $ 1,327,807 $ — $ 1,235 Investment properties 1,763 132 2,503 4,398 16,724 1,744,231 1,765,353 — 2,516 Multifamily real estate 4 — — 4 1,994 470,978 472,976 — — Commercial construction — — — — — 72,103 72,103 — — Multifamily construction 771 13 — 784 — 63,062 63,846 — — One- to four-family construction 2,466 220 — 2,686 905 274,878 278,469 — 1,233 Land and land development: Residential — — 747 747 77 125,949 126,773 — 1,027 Commercial — 96 — 96 4,668 28,415 33,179 — — Commercial business 1,844 174 1,024 3,042 7,302 1,197,600 1,207,944 8 2,159 Agricultural business/farmland 323 729 278 1,330 1,529 373,672 376,531 — 697 One- to four-family residential (1) 620 873 3,811 5,304 1,066 946,263 952,633 899 4,700 Consumer: Consumer secured by one- to four-family 465 60 38 563 40 477,817 478,420 4 565 Consumer—other 488 155 131 774 34 157,662 158,470 41 138 Total $ 12,725 $ 2,591 $ 9,417 $ 24,733 $ 58,600 $ 7,231,171 $ 7,314,504 $ 952 $ 14,270 December 31, 2014 30–59 Days Past Due 60–89 Days Past Due 90 Days or More Past Due Total Past Due Purchased Credit-Impaired Current Total Loans Loans 90 Days or More Past Due and Accruing Non-accrual Commercial real estate: Owner-occupied $ — $ 1,984 $ — $ 1,984 $ — $ 544,799 $ 546,783 $ — $ 1,100 Investment properties 639 — — 639 — 856,303 856,942 — 32 Multifamily real estate — — — — — 167,524 167,524 — — Commercial construction — — — — — 17,337 17,337 — 1,275 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 — 537 Agricultural business/farmland 597 466 744 1,807 — 236,692 238,499 — 1,597 One- to four-family residential (1) 877 1,623 7,526 10,026 — 527,082 537,108 2,095 8,834 Consumer: Consumer secured by one- to four-family 59 60 139 258 — 221,947 222,205 80 1,187 Consumer—other 491 88 293 872 — 126,131 127,003 — — Total $ 5,037 $ 4,256 $ 9,552 $ 18,845 $ — $ 3,812,189 $ 3,831,034 $ 2,175 $ 14,562 (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, 2015 and 2014 were $4 million and $8 million , respectively.
Schedule of Loans Receivable, Including Loans Held for Sale	Loans receivable at December 31, 2015 and 2014 are summarized as follows (dollars in thousands): December 31, 2015 December 31, 2014 Amount Percent of Total Amount Percent of Total Commercial real estate: Owner-occupied $ 1,327,807 18.2 % $ 546,783 14.3 % Investment properties 1,765,353 24.1 856,942 22.3 Multifamily real estate 472,976 6.5 167,524 4.4 Commercial construction 72,103 1.0 17,337 0.4 Multifamily construction 63,846 0.9 60,193 1.6 One- to four-family construction 278,469 3.8 219,889 5.7 Land and land development: Residential 126,773 1.7 102,435 2.7 Commercial 33,179 0.5 11,152 0.3 Commercial business 1,207,944 16.5 723,964 18.9 Agricultural business, including secured by farmland 376,531 5.1 238,499 6.2 One- to four-family residential 952,633 13.0 537,108 14.1 Consumer: Consumer secured by one- to four-family 478,420 6.5 222,205 5.8 Consumer—other 158,470 2.2 127,003 3.3 Total loans outstanding 7,314,504 100.0 % 3,831,034 100.0 % Less allowance for loan losses (78,008 ) (75,907 ) Net loans $ 7,236,496 $ 3,755,127 Loan amounts are net of unearned loan fees in excess of unamortized costs of $5.5 million at December 31, 2015 and $5.8 million at December 31, 2014 . Net loans include net discounts on acquired loans of $43.7 million and $148,000 as of December 31, 2015 and 2014 , respectively.
Schedule of Purchased Credit-Impaired Loans, Changes in Accretable Yield	The following table presents the changes in the accretable yield for PCI loans for the years ended December 31, 2015 and 2014 (in thousands): Years Ended December 31 2015 2014 Balance, beginning of period $ — $ — Additions 13,310 — Accretion to interest income (2,202 ) — Disposals and other (1,238 ) — Reclassifications from non-accretable difference 505 — Balance, end of period $ 10,375 $ —
Schedule of Impaired Loans With and Without Specific Reserves	The following tables provide additional information on impaired loans, excluding purchased credit impaired loans, with and without specific allowance reserves at December 31, 2015 and 2014 . Recorded investment includes the unpaid principal balance or the carrying amount of loans less charge-offs and net deferred loan fees (in thousands): December 31, 2015 Unpaid Principal Balance Recorded Investment Related Allowance Without Allowance (1) With Allowance (2) Commercial real estate: Owner-occupied $ 1,465 $ — $ 1,416 $ 70 Investment properties 8,740 2,503 5,846 602 Multifamily real estate 359 — 357 71 Commercial construction 1,141 1,069 — — One- to four-family construction 1,741 — 1,741 161 Land and land development: Residential 3,540 750 1,634 444 Commercial 1,628 1,027 — Commercial business 2,266 538 1,184 150 Agricultural business/farmland 1,309 544 697 43 One- to four-family residential 17,897 2,206 14,418 736 Consumer: Consumer secured by one- to four-family 776 — 716 23 Consumer—other 433 — 351 7 $ 41,295 $ 8,637 $ 28,360 $ 2,307 December 31, 2014 Unpaid Principal Balance Recorded Investment Related Allowance Without Allowance (1) With Allowance (2) Commercial real estate: Owner-occupied $ 1,598 $ 966 $ 582 $ 24 Investment properties 6,458 30 6,023 729 Multifamily real estate 786 — 786 86 One- to four-family construction 3,923 — 3,923 640 Land and land development: Residential 3,710 1,275 1,280 346 Commercial business 1,502 — 1,276 128 Agricultural business/farmland 1,597 744 854 26 One- to four-family residential 27,855 1,865 24,529 1,032 Consumer: Consumer secured by one- to four-family 1,256 73 1,077 75 Consumer—other 634 138 470 6 $ 49,319 $ 5,091 $ 40,800 $ 3,092 (1) Loans without an allowance reserve have been individually evaluated for impairment and that evaluation concluded that no reserve was needed. (2) Includes general reserves for loans evaluated in pools of homogeneous loans and loans with a specific reserve allowance. 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 less costs to sell to establish realizable value. The following tables summarize our average recorded investment and interest income recognized on impaired loans by loan class for the years ended December 31, 2015 , 2014 and 2013 (in thousands): Year Ended December 31, 2015 Year Ended December 31, 2014 Year Ended December 31, 2013 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Commercial real estate: Owner-occupied $ 1,467 $ 9 $ 1,841 $ 12 $ 2,761 $ 12 Investment properties 8,003 303 6,145 315 8,977 241 Multifamily real estate 362 18 795 45 5,705 298 One- to four-family construction 1,463 114 2,655 118 5,870 239 Land and land development: Residential 2,406 49 2,872 89 6,053 221 Commercial 931 — — — — — Commercial business 1,667 35 1,328 41 2,236 59 Agricultural business/farmland 1,143 19 1,866 — 110 8 One- to four-family residential 17,770 630 26,093 870 40,557 1,063 Consumer: Consumer secured by one- to four-family 736 11 1,248 19 1,403 25 Consumer—other 392 18 597 19 677 29 $ 36,340 $ 1,206 $ 45,440 $ 1,528 $ 74,349 $ 2,195
Schedule of Troubled Debt Restructurings	The following tables present TDRs at December 31, 2015 and 2014 (in thousands): December 31, 2015 December 31, 2014 Accrual Status Nonaccrual Status Total TDRs Accrual Nonaccrual Total Commercial real estate: Owner-occupied $ 181 $ 104 $ 285 $ 183 $ 109 $ 292 Investment properties 5,834 13 5,847 6,021 32 6,053 Multifamily real estate 357 — 357 786 — 786 One- to four-family construction 1,741 — 1,741 3,923 — 3,923 Land and land development: Residential 1,151 483 1,634 1,279 525 1,804 Commercial business 624 — 624 739 87 826 Agricultural business/farmland 545 277 822 — — — One- to four-family residential 11,025 1,428 12,453 15,793 1,363 17,156 Consumer: Consumer secured by one- to four-family 147 14 161 233 117 350 Consumer—other 172 — 172 197 116 313 $ 21,777 $ 2,319 $ 24,096 $ 29,154 $ 2,349 $ 31,503 As of December 31, 2015 and 2014 , the Company had commitments to advance funds up to an additional amount of $237,000 and $2.1 million , respectively, related to TDRs.
Schedule of Newly Restructured Loans	The following table presents new TDRs that occurred during the years ended December 31, 2015 and 2014 (dollars in thousands): Year Ended December 31, 2015 Year Ended December 31, 2014 Number of Contracts Pre-modification Outstanding Recorded Investment Post-modification Outstanding Recorded Investment Number of Pre-modification Outstanding Recorded Investment Post-modification Outstanding Recorded Investment Recorded Investment (1) (2) Commercial real estate: Owner-occupied — $ — $ — 1 $ 203 $ 203 One- to four-family construction — — — 10 2,153 2,153 Land and land development: Residential 2 1,302 483 — — — Commercial business — — — 1 100 100 Agricultural business/farmland 3 822 822 — — — One- to four-family residential 2 431 431 4 905 862 Consumer: Consumer - other — — — 1 9 9 7 $ 2,555 $ 1,736 17 $ 3,370 $ 3,327 (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, 2015 and 2014 , 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 2015 2014 Number of Loans Amount Number of Loans Amount Agricultural business/farmland 2 $ 277 — $ — One- to four-family residential 1 387 — — Total 3 $ 664 — $ —
Financing Receivable Credit Quality Indicators [Table Text Block]	The following tables show Banner’s portfolio of risk-rated loans and non-risk-rated loans by grade or other characteristic as of December 31, 2015 and 2014 (in thousands): December 31, 2015 Commercial Real Estate Multifamily Real Estate Construction and Land Commercial Business Agricultural Business One- to Four-Family Residential Consumer Total Loans Risk-rated loans: Pass (Risk Ratings 1-5) (1) $ 3,022,281 $ 468,467 $ 558,425 $ 1,167,933 $ 354,760 $ 943,098 $ 633,734 $ 7,148,698 Special mention 30,928 138 2,386 25,286 17,526 1,346 22 77,632 Substandard 39,951 4,371 13,559 14,725 4,245 8,189 3,124 88,164 Doubtful — — — — — — 10 10 Loss — — — — — — — — Total loans $ 3,093,160 $ 472,976 $ 574,370 $ 1,207,944 $ 376,531 $ 952,633 $ 636,890 $ 7,314,504 Performing loans $ 3,048,424 $ 470,982 $ 566,460 $ 1,198,475 $ 374,305 $ 945,968 $ 636,068 $ 7,240,682 Purchased credit-impaired loans 40,985 1,994 5,650 7,302 1,529 1,066 74 58,600 Non-performing loans (2) 3,751 — 2,260 2,167 697 5,599 748 15,222 Total loans $ 3,093,160 $ 472,976 $ 574,370 $ 1,207,944 $ 376,531 $ 952,633 $ 636,890 $ 7,314,504 December 31, 2014 Commercial Real Estate Multifamily Real Estate Construction and Land Commercial Business Agricultural Business One- to Four-Family Residential Consumer Total Loans Risk-rated loans: Pass (Risk Ratings 1-5) (1) $ 1,375,885 $ 166,712 $ 395,356 $ 691,143 $ 234,101 $ 524,598 $ 346,456 $ 3,734,251 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 Loss — — — — — — — — Total loans $ 1,403,725 $ 167,524 $ 411,006 $ 723,964 $ 238,499 $ 537,108 $ 349,208 $ 3,831,034 Performing loans $ 1,402,328 $ 167,524 $ 409,731 $ 723,427 $ 236,902 $ 526,506 $ 347,880 $ 3,814,298 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 $ 537,108 $ 349,208 $ 3,831,034 (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, 2015 and 2014 , in the commercial business category, $150 million and $115 million , respectively, of credit-scored small business loans. As loans in these pools become non-performing, they are individually risk-rated. (2) Non-performing loans include non-accrual loans and loans past due greater than 90 days but still on accrual status.

REAL ESTATE OWNED, HELD FOR S38

REAL ESTATE OWNED, HELD FOR SALE, NET (Tables)	12 Months Ended
	Dec. 31, 2015
Real Estate [Abstract]
Schedule of Changes in Real Estate Owned, Net of Valuation Allowance	The following table presents the changes in REO, net of valuation allowance, for the years ended December 31, 2015 , 2014 and 2013 (in thousands): Years Ended December 31 2015 2014 2013 Balance, beginning of period $ 3,352 $ 4,044 $ 15,778 Additions from loan foreclosures 4,351 3,264 3,166 Additions from capitalized costs 298 30 348 Additions from acquisitions 8,231 — — Proceeds from dispositions of REO (4,740 ) (4,923 ) (16,944 ) Gain on sale of REO 351 973 2,481 Valuation adjustments in the period (216 ) (36 ) (785 ) Balance, end of period $ 11,627 $ 3,352 $ 4,044

PROPERTY AND EQUIPMENT, NET (Ta

PROPERTY AND EQUIPMENT, NET (Tables)	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Land, buildings and equipment owned by the Company and its subsidiaries at December 31, 2015 and 2014 are summarized as follows (in thousands): December 31 2015 2014 Land $ 38,992 $ 21,969 Buildings and leasehold improvements 160,075 98,901 Furniture and equipment 79,018 72,152 278,085 193,022 Less accumulated depreciation (110,481 ) (101,837 ) Property and equipment, net $ 167,604 $ 91,185
Schedule of Future Minimum Rental Payments for Operating Leases	The Company’s obligations under long-term property leases are as follows: Year Amount 2016 $ 14.3 million 2017 12.9 million 2018 10.7 million 2019 7.8 million 2020 6.6 million Thereafter 23.0 million Total $ 75.3 million

DEPOSITS (Tables)

DEPOSITS (Tables)	12 Months Ended
	Dec. 31, 2015
Banking and Thrift [Abstract]
Schedule of Deposit Liabilities	Deposits consist of the following at December 31, 2015 and 2014 (in thousands): December 31 2015 2014 Non-interest-bearing checking $ 2,619,618 $ 1,298,866 Interest-bearing checking 1,159,846 439,480 Regular savings accounts 1,284,642 901,142 Money market accounts 1,637,092 488,946 Total transaction and savings accounts 6,701,198 3,128,434 Certificates of deposit: Certificates of deposit less than or equal to the FDIC insured limit of $250,000 1,168,495 633,345 Certificates of deposit greater than the FDIC insured limit of $250,000 185,375 137,171 Total certificates of deposit 1,353,870 770,516 Total deposits $ 8,055,068 $ 3,898,950 Included in total deposits: Public fund transaction accounts $ 209,430 $ 102,854 Public fund interest-bearing certificates 31,281 35,346 Total public deposits $ 240,711 $ 138,200 Total brokered deposits $ 162,936 $ 4,799 Deposits at December 31, 2015 and 2014 included deposits from the Company’s directors, executive officers and related entities totaling $6.6 million and $6.2 million , 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, 2015 are as follows (dollars in thousands): December 31, 2015 Amount Weighted Average Rate Maturing in one year or less $ 985,193 0.48 % Maturing after one year through two years 226,381 0.88 Maturing after two years through three years 88,184 1.05 Maturing after three years through four years 24,981 1.17 Maturing after four years through five years 25,917 1.26 Maturing after five years 3,214 1.10 Total certificates of deposit $ 1,353,870 0.61 %

ADVANCES FROM FEDERAL HOME LO41

ADVANCES FROM FEDERAL HOME LOAN BANK OF DES MOINES (Tables)	12 Months Ended
	Dec. 31, 2015
Advances from Federal Home Loan Banks [Abstract]
Schedule of Federal Home Loan Bank Advances, Fiscal Year Maturity	At December 31, 2015 and 2014 , FHLB advances were scheduled to mature as follows (dollars in thousands): December 31 2015 2014 Maturing in one year or less $ 107,600 $ 32,000 Maturing after one year through three years 25,000 — Maturing after three years through five years — — Maturing after five years 188 196 Total FHLB advances, at par 132,788 32,196 Fair value adjustment 593 54 Total FHLB advances, carried at fair value $ 133,381 $ 32,250

OTHER BORROWINGS (Tables)

OTHER BORROWINGS (Tables)	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Schedule of Other Borrowings, Maturity	A summary of all other borrowings at December 31, 2015 and 2014 by the period remaining to maturity is as follows (dollars in thousands): At or for the Years Ended December 31 2015 2014 Amount Weighted Average Rate Amount Weighted Average Rate Repurchase agreements: Maturing in one year or less $ 93,325 0.19 % $ 77,185 0.20 % Maturing after one year through two years — — — — Maturing after two years 5,000 2.15 — — Total year-end outstanding $ 98,325 0.29 $ 77,185 0.20 Average outstanding $ 94,182 0.22 $ 83,965 0.20 Maximum outstanding at any month-end 102,474 n/a 89,921 n/a

JUNIOR SUBORDINATED DEBENTURE43

JUNIOR SUBORDINATED DEBENTURES AND MANDATORILY REDEEMABLE TRUST PREFERRED SECURITIES (Tables)	12 Months Ended
	Dec. 31, 2015
Other Liabilities Disclosure [Abstract]
Schedule of Trust Preferred Securities	The following table is a summary of trust preferred securities at December 31, 2015 (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 (1) Current Interest Rate Reset Period Interest Rate Spread Banner Capital Trust II $ 15,000 $ 464 $ 15,464 2033 3.96 % Quarterly Three-month LIBOR + 3.35% Banner Capital Trust III 15,000 465 15,465 2033 3.51 Quarterly Three-month LIBOR + 2.90% Banner Capital Trust IV 15,000 465 15,465 2034 3.46 Quarterly Three-month LIBOR + 2.85% Banner Capital Trust V 25,000 774 25,774 2035 2.18 Quarterly Three-month LIBOR + 1.57% Banner Capital Trust VI 25,000 774 25,774 2037 2.23 Quarterly Three-month LIBOR + 1.62% Banner Capital Trust VII 25,000 774 25,774 2037 1.99 Quarterly Three-month LIBOR + 1.38% Siuslaw Statutory Trust I 8,000 248 8,248 2034 3.31 Quarterly Three-month LIBOR + 2.70% Greater Sacramento Bancorp Statutory Trust I 4,000 124 4,124 2033 3.96 Quarterly Three-month LIBOR + 3.35% Greater Sacramento Bancorp Statutory Trust II 4,000 124 4,124 2035 2.29 Quarterly Three-month LIBOR + 1.68% Total TPS liability at par $ 136,000 $ 4,212 140,212 2.76 % Fair value adjustment (47,732 ) Total TPS liability at fair value $ 92,480 (1) All of the Company's trust preferred securities are eligible for redemption.

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	The following table presents the components of the provision for income taxes included in the Consolidated Statements of Operations for the years ended December 31, 2015 , 2014 and 2013 (in thousands): Years Ended December 31 2015 2014 2013 Current Federal $ 24,683 $ 23,411 $ 11,829 State 1,399 1,444 292 Total Current 26,082 24,855 12,121 Deferred Federal (3,310 ) 2,764 10,936 State (23 ) (567 ) 1,132 Total Deferred (3,333 ) 2,197 12,068 Increase (decrease) in valuation allowance — — — Provision for income taxes $ 22,749 $ 27,052 $ 24,189
Schedule of Effective Income Tax Rate Reconciliation	The following tables present the reconciliation of the federal statutory rate to the actual effective rate for the years ended December 31, 2015 , 2014 and 2013 (dollars in thousands): Years Ended December 31 2015 2014 2013 Federal income tax statutory rate 35.0 % 35.0 % 35.0 % Increase (decrease) in tax rate due to: Tax-exempt interest (3.9 ) (2.6 ) (2.4 ) Investment in life insurance (1.3 ) (0.8 ) (1.0 ) State income taxes, net of federal tax offset 1.1 1.1 1.2 Tax credits (1.6 ) (0.8 ) (0.9 ) Merger and acquisition costs 1.9 0.7 — Other 2.3 0.7 2.5 Effective income tax rate 33.5 % 33.3 % 34.4 %
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, 2015 and 2014 (in thousands): December 31 2015 2014 Deferred tax assets: Loan loss and REO $ 33,312 $ 26,536 Deferred compensation 19,253 9,223 Net operating loss carryforward 91,893 17,577 Federal and state tax credits 7,877 3,676 State net operating losses 8,692 1,009 Loan discount 13,412 (1,190 ) Other 5,620 1,344 Total deferred tax assets 180,059 58,175 Deferred tax liabilities: FHLB stock dividends — (4,805 ) Depreciation (1,103 ) (4,479 ) Deferred loan fees, servicing rights and loan origination costs (9,884 ) (7,843 ) Intangibles (13,320 ) (975 ) Financial instruments accounted for under fair value accounting (17,112 ) (15,611 ) Unrealized (gain) loss on securities - available-for-sale (1,475 ) 145 Total deferred tax liabilities (42,894 ) (33,568 ) Deferred income tax asset 137,165 24,607 Valuation allowance (2,195 ) — Deferred tax asset, net $ 134,970 $ 24,607

STOCK-BASED COMPENSATION PLANS

STOCK-BASED COMPENSATION PLANS (Tables)	12 Months Ended
	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Stock Option Award Activity	A summary of the Company’s stock option award activity for the years ended December 31, 2013 , 2014 and 2015 follows: Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term, In Years Aggregate Intrinsic Value 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 1.90 n/a Granted — — Exercised — — Forfeited (5,664 ) 197.11 Outstanding at December 31, 2015 5,000 216.16 n/a n/a Outstanding at December 31, 2015 , net of expected forfeitures — — n/a n/a Exercisable at December 31, 2015 5,000 216.16 1.58 —
Schedule of Financial Data Pertaining to Outstanding Stock Options, by Exercise Price Range	At December 31, 2015 , 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 $ 216.16 $ 216.16 5,000 5,000 $ 216.16 1.6 years
Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity	A summary of the Company's Restricted Stock/Unit award activity during the years ended December 31, 2013 , 2014 and 2015 follows: Shares/Units Weighted Average Grant-Date Fair Value 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 ) 31.00 Unvested at December 31, 2014 195,106 32.83 Granted 155,183 45.59 Vested (109,416 ) 30.28 Forfeited (9,311 ) 39.07 Unvested at December 31, 2015 231,562 42.33

REGULATORY CAPITAL REQUIREMEN46

REGULATORY CAPITAL REQUIREMENTS (Tables)	12 Months Ended
	Dec. 31, 2015
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, 2015: The Company—consolidated: Total capital to risk-weighted assets $ 1,139,554 13.63 % $ 668,941 8.00 % n/a n/a Tier 1 capital to risk-weighted assets 1,057,597 12.65 501,706 6.00 n/a n/a Tier 1 common equity to risk-weighted assets 1,013,971 12.13 376,279 4.50 n/a n/a Tier 1 capital to average leverage assets 1,057,597 11.06 382,617 4.00 n/a n/a Banner Bank: Total capital to risk- weighted assets 1,030,601 12.61 653,606 8.00 $ 817,008 10.00 Tier 1 capital to risk- weighted assets 950,865 11.64 490,205 6.00 653,606 8.00 Tier 1 common equity to risk-weighted assets 950,865 11.64 367,653 4.50 531,055 6.50 Tier 1 capital to average leverage assets 950,865 10.23 371,807 4.00 464,759 5.00 Islanders Bank: Total capital to risk- weighted assets 38,448 20.31 15,146 8.00 18,932 10.00 Tier 1 capital to risk- weighted assets 36,227 19.14 11,359 6.00 15,146 8.00 Tier 1 common equity to risk-weighted assets 36,227 19.14 8,520 4.50 12,306 6.50 Tier 1 capital to average leverage assets 36,227 13.38 10,826 4.00 13,533 5.00 December 31, 2014: The Company—consolidated: Total capital to risk-weighted assets $ 684,583 16.80 % $ 326,071 8.00 % n/a n/a Tier 1 capital to risk-weighted assets 633,317 15.54 163,036 4.00 n/a n/a Tier 1 capital to average leverage assets 633,317 13.41 188,885 4.00 n/a n/a Banner Bank: Total capital to risk- weighted assets 605,997 15.53 312,220 8.00 $ 390,274 10.00 % Tier 1 capital to risk- weighted assets 556,897 14.27 156,110 4.00 234,165 6.00 Tier 1 capital to average leverage assets 556,897 12.42 179,304 4.00 224,130 5.00 Islanders Bank: Total capital to risk- weighted assets 36,590 19.92 14,693 8.00 18,367 10.00 Tier 1 capital to risk- weighted assets 34,332 18.69 7,347 4.00 11,020 6.00 Tier 1 capital to average leverage assets 34,332 13.68 10,040 4.00 12,550 5.00

OTHER INTANGIBLE ASSETS AND M47

OTHER INTANGIBLE ASSETS AND MORTGAGE SERVICING RIGHTS (Tables)	12 Months Ended
	Dec. 31, 2015
Other Intangible Assets and Mortgage Servicing Rights [Abstract]
Schedule of Changes in Intangible Assets	The following table summarizes the changes in the Company’s goodwill and CDI for the years ended December 31, 2013 , 2014 and 2015 (in thousands): Goodwill CDI Total 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 Additions through acquisition 247,738 37,395 285,133 Amortization — (3,164 ) (3,164 ) Other changes (1) — (300 ) (300 ) Balance, December 31, 2015 $ 247,738 $ 36,762 $ 284,500
Schedule of Estimated Annual Amortization Expense	Estimated amortization expense in future years with respect to existing intangibles as of December 31, 2015 (in thousands): Year ended: CDI 2016 $ 7,061 2017 6,332 2018 5,610 2019 4,889 Thereafter 12,870 Net carrying amount $ 36,762
Schedule of Mortgage Servicing Rights at Amortized Value	An analysis of the mortgage servicing rights for the years ended December 31, 2015 , 2014 and 2013 is presented below (in thousands): Years Ended December 31 2015 2014 2013 Balance, beginning of the year $ 9,030 $ 8,086 $ 6,244 Amounts capitalized 5,313 3,023 2,913 Additions through acquisition 2,172 — — Amortization (1) (3,220 ) (2,079 ) (2,371 ) Valuation adjustments in the period — — 1,300 Balance, end of the year (2) $ 13,295 $ 9,030 $ 8,086 (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) There was no valuation allowance as of December 31, 2015 , 2014 and 2013 .

FAIR VALUE OF FINANCIAL INSTR48

FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
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, 2015 and 2014 , whether or not recognized or recorded in the Consolidated Statements of Financial Condition (in thousands): December 31, 2015 December 31, 2014 Level Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value Assets: Cash and due from banks 1 $ 261,917 $ 261,917 $ 126,072 $ 126,072 Securities—trading 2,3 34,134 34,134 40,258 40,258 Securities—available-for-sale 2 1,138,573 1,138,573 411,021 411,021 Securities—held-to-maturity 3 220,666 226,627 131,258 137,608 Loans receivable held for sale 2 44,712 45,600 2,786 2,807 Loans receivable 3 7,314,504 7,084,631 3,831,034 3,722,179 FHLB stock 3 16,057 16,057 27,036 27,036 BOLI 1 156,865 156,865 63,759 63,759 Mortgage servicing rights 3 13,295 17,370 9,030 12,987 Derivatives: Interest rate swaps 2 11,984 11,984 6,290 6,290 Interest rate lock commitments 2 471 471 317 317 Liabilities: Demand, interest-bearing checking and money market 2 5,416,556 5,416,556 2,227,292 2,227,292 Regular savings 2 1,284,642 1,284,642 901,142 901,142 Certificates of deposit 2 1,353,870 1,332,825 770,516 770,516 Advances from FHLB at fair value 2 133,381 133,381 32,250 32,250 Junior subordinated debentures at fair value 3 92,480 92,480 78,001 78,001 Other borrowings 2 98,325 98,325 77,185 77,185 Derivatives: Interest rate swaps 2 11,984 11,984 6,290 6,290 Interest rate forward sales commitments 2 50 50 198 198
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, 2015 and 2014 (in thousands): December 31, 2015 Level 1 Level 2 Level 3 Total Assets: Securities—trading U.S. Government and agency $ — $ 1,368 $ — $ 1,368 Municipal bonds — 341 — 341 TPS and TRUP CDOs (1) — — 18,699 18,699 Mortgage-backed securities — 13,663 — 13,663 Equity securities — 63 — 63 — 15,435 18,699 34,134 Securities—available-for-sale U.S. Government and agency — 30,231 — 30,231 Municipal bonds — 143,319 — 143,319 Corporate bonds — 15,981 — 15,981 Mortgage-backed securities — 918,259 — 918,259 Asset-backed securities — 30,685 — 30,685 Equity securities — 98 — 98 — 1,138,573 — 1,138,573 Derivatives Interest rate swaps — 11,984 — 11,984 Interest rate lock commitments — 471 — 471 $ — $ 1,166,463 $ 18,699 $ 1,185,162 Liabilities Advances from FHLB at fair value $ — $ 133,381 $ — $ 133,381 Junior subordinated debentures at fair value — — 92,480 92,480 Derivatives Interest rate swaps — 11,984 — 11,984 Interest rate forward sales commitments — 50 — 50 $ — $ 145,415 $ 92,480 $ 237,895 (1) Pooled trust preferred collateralized debt obligation securities (TRUP CDOs) 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 — 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 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
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, 2015 and 2014 : December 31 2015 2014 Financial Instruments Valuation Technique Unobservable Inputs Weighted Average Rate Weighted Average Rate TPS securities Discounted cash flows Discount rate 5.61 % 5.26 % TRUP CDOs Discounted cash flows Discount rate n/a 3.96 Junior subordinated debentures Discounted cash flows Discount rate 5.61 5.26 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 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, 2015 and 2014 (in thousands): Year Ended December 31, 2015 Level 3 Fair Value Inputs TPS and TRUP CDOs Borrowings— Junior Subordinated Debentures Beginning balance at December 31, 2014 $ 19,119 $ 78,001 Total gains or losses recognized Assets gains 537 — Liabilities losses — 2,714 Purchases, issuances and settlements, net 5,697 11,765 Paydowns and maturities (6,654 ) — Transfers in and/or out of Level 3 — — Ending balance at December 31, 2015 $ 18,699 $ 92,480 Year Ended December 31, 2014 Level 3 Fair Value Inputs TPS and TRUP CDOs Borrowings— Junior Subordinated Debentures Beginning balance at December 31, 2013 $ 35,140 $ 73,928 Total gains or losses recognized Assets gains 5,481 — Liabilities 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
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 of the fair value measurements for those assets at December 31, 2015 and 2014 (in thousands): At or For the Year Ended December 31, 2015 Level 1 Level 2 Level 3 Total Impaired loans $ — $ — $ 2,372 $ 2,372 REO — — 11,627 11,627 At or For the Year Ended December 31, 2014 Level 1 Level 2 Level 3 Total Impaired loans $ — $ — $ 4,725 $ 4,725 REO — — 3,352 3,352 The following table presents the losses resulting from non-recurring fair value adjustments for the years ended December 31, 2015 and 2014 (in thousands): For the twelve months ended December 31, 2015 2014 Impaired loans $ (110 ) $ (512 ) REO (231 ) (453 ) Total loss from nonrecurring measurements $ (341 ) $ (965 )

BANNER CORPORATION (PARENT CO49

BANNER CORPORATION (PARENT COMPANY ONLY) (Tables)	12 Months Ended
	Dec. 31, 2015
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 December 31 2015 2014 ASSETS Cash $ 58,232 $ 52,124 Investment in trust equities 4,212 3,716 Investment in subsidiaries 1,319,348 610,732 Other assets 21,134 8,279 $ 1,402,926 $ 674,851 LIABILITIES AND SHAREHOLDERS’ EQUITY Miscellaneous liabilities $ 7,846 $ 2,446 Deferred tax liability 2,541 11,516 Junior subordinated debentures at fair value 92,480 78,001 Shareholders’ equity 1,300,059 582,888 $ 1,402,926 $ 674,851
Schedule of Condensed Statement of Operations	Statements of Operations Years Ended December 31 2015 2014 2013 INTEREST INCOME: Interest-bearing deposits $ 122 $ 96 $ 82 OTHER INCOME (EXPENSE): Dividend income from subsidiaries 170,260 26,027 24,725 Equity in undistributed (distributions in excess of) income of subsidiaries (116,120 ) 33,612 23,653 Other income 69 67 3,016 Net change in valuation of financial instruments carried at fair value (2,714 ) (4,073 ) (865 ) Interest on other borrowings (3,247 ) (2,914 ) (2,968 ) Other expenses (7,175 ) (2,519 ) (2,794 ) Net income before taxes 41,195 50,296 44,849 BENEFIT FROM INCOME TAXES (4,027 ) (3,774 ) (1,365 ) NET INCOME $ 45,222 $ 54,070 $ 46,214
Schedule of Condensed Statement of Cash Flows	Statements of Cash Flows Years Ended December 31 2015 2014 2013 OPERATING ACTIVITIES: Net income $ 45,222 $ 54,070 $ 46,214 Adjustments to reconcile net income to net cash provided by operating activities: Distributions in excess of (Equity in undistributed) income of subsidiaries 116,120 (33,612 ) (23,653 ) Increase (decrease) in deferred taxes (1,398 ) (1,444 ) 17 Net change in valuation of financial instruments carried at fair value 2,714 4,073 865 Increase in other assets (10,655 ) (3,822 ) (4,655 ) Increase (decrease) in other liabilities 3,919 222 (1,921 ) Net cash provided from operating activities 155,922 19,487 16,867 INVESTING ACTIVITIES: Funds transferred to deferred compensation trust (26 ) (26 ) (27 ) Acquisitions (132,652 ) — — Net cash used by investing activities (132,678 ) (26 ) (27 ) FINANCING ACTIVITIES: Issuance of stock for shareholder reinvestment program 34 127 72 Cash dividends paid (17,170 ) (13,462 ) (7,798 ) Net cash used by financing activities (17,136 ) (13,335 ) (7,726 ) NET CHANGE IN CASH 6,108 6,126 9,114 CASH, BEGINNING OF PERIOD 52,124 45,998 36,884 CASH, END OF PERIOD $ 58,232 $ 52,124 $ 45,998

CALCULATION OF EARNINGS PER C50

CALCULATION OF EARNINGS PER COMMON SHARE (Tables)	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Weighted Shares Outstanding	The following tables show the calculation of earnings per common share (in thousands, except per share data): Years Ended December 31 2015 2014 2013 Net income $ 45,222 $ 54,070 $ 46,214 Weighted average number of common shares outstanding Basic 23,801,373 19,359,409 19,361,411 Diluted 23,866,621 19,402,656 19,397,360 Earnings per common share Basic $ 1.90 $ 2.79 $ 2.39 Diluted $ 1.89 $ 2.79 $ 2.38

SELECTED QUARTERLY FINANCIAL 51

SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Tables)	12 Months Ended
	Dec. 31, 2015
Selected Quarterly Financial Information [Abstract]
Schedule of Quarterly Financial Information	Results of operations on a quarterly basis for the years ended December 31, 2015 , 2014 and 2013 were as follows (dollars in thousands except for per share data): Year Ended December 31, 2015 First Quarter Second Quarter Third Quarter Fourth Quarter Interest income $ 49,069 $ 54,076 $ 54,793 $ 96,495 Interest expense 2,533 2,619 2,605 4,396 Net interest income before provision for loan losses 46,536 51,457 52,188 92,099 Provision for loan losses — — — — Net interest income 46,536 51,457 52,188 92,099 Non-interest income 13,696 16,141 14,098 18,356 Non-interest expense 41,914 47,734 46,697 100,254 Income before provision for income taxes 18,318 19,864 19,589 10,201 Provision for income taxes 6,184 6,615 6,642 3,308 Net income $ 12,134 $ 13,249 $ 12,947 $ 6,893 Basic earnings per share $ 0.61 $ 0.64 $ 0.62 $ 0.20 Diluted earnings per share 0.61 0.64 0.62 0.20 Dividends declared 0.18 0.18 0.18 0.18 Year Ended December 31, 2014 First Quarter Second Quarter Third Quarter Fourth 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 Non-interest income 9,032 20,310 13,536 12,113 Non-interest expense 35,581 38,435 38,495 41,230 Income before provision for income taxes 15,790 25,683 22,105 17,544 Provision for income taxes 5,241 8,696 7,284 5,831 Net income $ 10,549 $ 16,987 $ 14,821 $ 11,713 Basic earnings per share $ 0.55 $ 0.88 $ 0.76 $ 0.60 Diluted earnings per share 0.54 0.88 0.76 0.60 Dividends declared 0.18 0.18 0.18 0.18 Year Ended December 31, 2013 First Quarter Second Quarter Third Quarter Fourth Quarter Interest income $ 44,508 $ 45,571 $ 45,037 $ 44,596 Interest expense 3,540 3,323 3,144 2,989 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 Non-interest income 10,088 10,953 10,592 13,029 Non-interest expense 34,099 35,457 34,490 36,929 Income (loss) before provision for income taxes 16,957 17,744 17,995 17,707 Provision (benefit) for income taxes 5,373 6,076 6,459 6,281 Net income $ 11,584 $ 11,668 $ 11,536 $ 11,426 Basic earnings per share $ 0.60 $ 0.60 $ 0.60 $ 0.59 Diluted earnings per share 0.60 0.60 0.59 0.59 Dividends declared 0.12 0.12 0.15 0.15

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Schedule of Fair Value, Off-balance Sheet Risks [Table Text Block]	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, 2015 December 31, 2014 Commitments to extend credit $ 2,132,996 $ 1,166,165 Standby letters of credit and financial guarantees 22,315 9,934 Commitments to originate loans 32,908 20,988 Derivatives also included in Note 24: Commitments to originate loans held for sale 76,146 29,851 Commitments to sell loans secured by one- to four-family residential properties 37,545 8,714 Commitments to sell securities related to mortgage banking activities 41,500 25,000

DERIVATIVES AND HEDGING DERIV53

DERIVATIVES AND HEDGING DERIVATIVES AND HEDGING (Tables)	12 Months Ended
	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	As of December 31, 2015 and December 31, 2014 , 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, 2015 December 31, 2014 December 31, 2015 December 31, 2014 Notional/ Contract Amount Fair Value (1) Notional/ Contract Amount Fair Value (1) Notional/ Contract Amount Fair Value (2) Notional/ Contract Amount Fair Value (2) Interest rate swaps $ 6,734 $ 938 $ 7,089 $ 1,165 $ 6,734 $ 938 $ 7,089 $ 1,165 (1) Included in Loans Receivable on the Consolidated Statements of Financial Condition. (2) Included in Other Liabilities on the Consolidated Statements of Financial Condition.
Schedule of Other Derivatives Not Designated as Hedging Instruments, Statements of Financial Performance and Financial Position, Location	As of December 31, 2015 and December 31, 2014 , 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, 2015 December 31, 2014 December 31, 2015 December 31, 2014 Notional/ Contract Amount Fair Value (1) Notional/ Contract Amount Fair Value (1) Notional/ Contract Amount Fair Value (2) Notional/ Contract Amount Fair Value (2) Interest rate swaps $ 293,937 $ 11,046 $ 134,512 $ 5,125 $ 293,937 $ 11,046 $ 134,512 $ 5,125 Risk participation agreement — — — — 7,672 36 — — Mortgage loan commitments 76,146 428 29,311 317 — — — — Forward sales contracts 41,500 43 — — 32,763 50 33,174 198 $ 411,583 $ 11,517 $ 163,823 $ 5,442 $ 334,372 $ 11,132 $ 167,686 $ 5,323 (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 $327,000 at December 31, 2015 and $558,000 at December 31, 2014 ), 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, 2015 and 2014 were as follows (in thousands): For the Year Ended December 31 Location on Income Statement 2015 2014 Mortgage loan commitments Mortgage banking operations $ 100 $ 221 Forward sales contracts Mortgage banking operations 141 (188 ) $ 241 $ 33
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, 2015 and December 31, 2014 (in thousands): December 31, 2015 Gross Amounts of Financial Instruments Not Offset in the Statement of Financial Condition Gross Amounts Recognized Amounts offset in the Statement of Financial Condition Net Amounts in the Statement of Financial Condition Netting Adjustment Per Applicable Master Netting Agreements Fair Value of Financial Collateral in the Statement of Financial Condition Net Amount Derivative assets Interest rate swaps $ 11,984 $ — $ 11,984 $ — $ — $ 11,984 $ 11,984 $ — $ 11,984 $ — $ — $ 11,984 Derivative liabilities Interest rate swaps $ 11,984 $ — $ 11,984 $ — $ (11,984 ) $ — $ 11,984 $ — $ 11,984 $ — $ (11,984 ) $ — December 31, 2014 Gross Amounts of Financial Instruments Not Offset in the Statement of Financial Condition Gross Amounts Recognized Amounts offset in the Statement of Financial Condition Net Amounts in the Statement of Financial Condition Netting Adjustment Per Applicable Master Netting Agreements Fair Value of Financial Collateral in the Statement of Financial Condition Net Amount 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

BASIS OF PRESENTATION AND SUM54

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Investment in FHLB Stock) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Federal Home Loan Bank (FHLB) stock	$ 16,057	$ 27,036
Federal Home Loan Bank Stock, Par Value Per Share		$ 100
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 SUM55

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 SUM56

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Textuals) (Details) $ in Millions	12 Months Ended		20 Months Ended
	Dec. 31, 2015USD ($)shares	Dec. 31, 2014USD ($)subsidiaryofficelocation	Dec. 31, 2015USD ($)shares
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Number of wholly-owned subsidiaries | subsidiary		2
Cash surrender value of bank-owned life insurance policies	$ 156.9	$ 63.8	$ 156.9
Subsidiary, Banner Bank [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Number of offices | office		199
Number of production offices | office		9
Subsidiary, Islanders Bank [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Number of locations | location		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		10 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		$ 12
Other assets [Member] | Interest Rate Swap [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Derivative Asset, Notional Amount		$ 282
2014 Omnibus Incentive Plan [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Number of shares authorized | shares	900,000		900,000
Restricted Stock [Member] | 2014 Omnibus Incentive Plan [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Granted | shares			119,765

BUSINESS COMBINATIONS BUSINES57

BUSINESS COMBINATIONS BUSINESS COMBINATIONS (Textual) (Details) $ / shares in Units, shares in Thousands, $ in Thousands	Oct. 01, 2015USD ($)bank_branchshares	Mar. 06, 2015USD ($)$ / shares	Jun. 20, 2014USD ($)location	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)
Business Acquisition [Line Items]
Assets	$ 9,900,000			$ 9,796,298	$ 4,723,163
Number of Stores | bank_branch	203
Goodwill				247,738	0	$ 0	$ 0
Acquisition bargain purchase gain				$ 0	$ 9,079	$ 0
Starbuck Bancshares, Inc [Member]
Business Acquisition [Line Items]
Effective date of acquisition	Oct. 1, 2015
Cash paid	$ 130,000
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable, Shares | shares	13,230
Business Combination, Acquired Assets	$ 4,457,474
Business Combination, Acquired Deposits	3,638,596
Business Combination, Acquired Receivables	2,997,640
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	33,500
Goodwill	$ 226,047
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
Business Combination, Acquired Receivables, Non-Credit-Impaired	$ 2,950,000
Business Combination, Acquired Receivables, Non-Credit-Impaired, Fair Value	2,940,000
Business Combination, Acquired Receivables, Discount	17,700
Business Combination, Acquired Receivables, Non-Credit-Impaired, Cash Flows Not Expected to be Collected at Acquisition	44,100
Property and equipment	66,549
Cash and cash equivalents	$ 95,821
Siuslaw Financial Group, Inc [Member]
Business Acquisition [Line Items]
Effective date of acquisition		Mar. 6, 2015
Cash paid		$ 5,806
Business Combination, Acquired Assets		369,763
Business Combination, Acquired Deposits		316,406
Business Combination, Acquired Receivables		247,098
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles		3,895
Goodwill		21,691
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				8 years
Business Combination, Acquired Receivables, Non-Credit-Impaired		244,200
Business Combination, Acquired Receivables, Non-Credit-Impaired, Fair Value		241,400
Business Combination, Acquired Receivables, Discount		$ 2,800
Business Acquisition, Equity Interest Issued to Acquiree's Shareholders, Per Share | $ / shares		$ 0.32231
Business Acquisition, Cash Payment Issued to Acquiree's Shareholders, Per Share | $ / shares		$ 1.41622
Property and equipment		$ 8,127
Cash and cash equivalents		$ 84,405
Six Oregon Branches [Member]
Business Acquisition [Line Items]
Effective date of acquisition			Jun. 20, 2014
Business Combination, Number of Branches | location			6
Business Combination, Acquired Assets			$ 221,206
Business Combination, Acquired Deposits			212,085
Business Combination, Acquired Receivables			87,923
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles			2,372
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				8 years
Property and equipment			3,079
Cash and cash equivalents			127,557
Acquisition bargain purchase gain			9,079
Discount on net asset acquired			7,000
Net fair value adjustments on acquired assets and assumed liabilities			$ 300
Washington, Oregon, Idaho, California and Utah [Member] | Starbuck Bancshares, Inc [Member]
Business Acquisition [Line Items]
Business Combination, Number of Branches | bank_branch	98

BUSINESS COMBINATIONS BUSINES58

BUSINESS COMBINATIONS BUSINESS COMBINATIONS (Schedule of Components of Acquisition) (Details) - USD ($) $ in Thousands	Oct. 01, 2015	Mar. 06, 2015	Jun. 20, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
LIABILITIES
Goodwill				$ 247,738	$ 0	$ 0	$ 0
Acquisition bargain purchase gain				$ 0	$ 9,079	$ 0
Starbuck Bancshares, Inc [Member]
Business Acquisition [Line Items]
Effective date of acquisition	Oct. 1, 2015
Cash paid	$ 130,000
Fair value of common shares issued	630,674
Total consideration	760,674
ASSETS
Cash and cash equivalents	95,821
Securities	1,037,238
Loans receivable	2,997,640
REO, held for sale	5,706
Property and equipment	66,549
CDI	33,500
Deferred tax asset	107,847
Other assets	113,173
Total assets acquired	4,457,474
LIABILITIES
Deposits	3,638,596
FHLB advances	221,442
Junior subordinated debentures	5,806
Other liabilities	57,003
Total liabilities assumed	3,922,847
Net assets acquired	534,627
Goodwill	226,047
Contractual amount of acquired loans	$ 3,040,000
Siuslaw Financial Group, Inc [Member]
Business Acquisition [Line Items]
Effective date of acquisition		Mar. 6, 2015
Cash paid		$ 5,806
Fair value of common shares issued		58,100
Total consideration		63,906
ASSETS
Cash and cash equivalents		84,405
Securities		12,865
Loans receivable		247,098
REO, held for sale		2,525
Property and equipment		8,127
CDI		3,895
Other assets		10,848
Total assets acquired		369,763
LIABILITIES
Deposits		316,406
Junior subordinated debentures		5,959
Other liabilities		5,183
Total liabilities assumed		327,548
Net assets acquired		42,215
Goodwill		21,691
Contractual amount of acquired loans		$ 252,200
Six Oregon Branches [Member]
Business Acquisition [Line Items]
Effective date of acquisition			Jun. 20, 2014
Total consideration			$ 0
ASSETS
Cash and cash equivalents			127,557
Loans receivable			87,923
Property and equipment			3,079
CDI			2,372
Other assets			275
Total assets acquired			221,206
LIABILITIES
Deposits			212,085
Other liabilities			42
Total liabilities assumed			212,127
Net assets acquired			9,079
Acquisition bargain purchase gain			9,079
Contractual amount of acquired loans			$ 88,300

BUSINESS COMBINATIONS (Acquired

BUSINESS COMBINATIONS (Acquired PCI Loans) (Details) - USD ($) $ in Thousands	Oct. 01, 2015	Mar. 06, 2015
Starbuck Bancshares, Inc [Member]
Business Acquisition [Line Items]
Contractually required principal and interest payments	$ 98,746
Nonaccretable difference	(26,162)
Cash flows expected to be collected	72,584
Accretable yield	(11,071)
Fair value of PCI loans	$ 61,513
Siuslaw Financial Group, Inc [Member]
Business Acquisition [Line Items]
Contractually required principal and interest payments		$ 11,134
Nonaccretable difference		(3,238)
Cash flows expected to be collected		7,896
Accretable yield		(2,239)
Fair value of PCI loans		$ 5,657

BUSINESS COMBINATIONS (Pro Form

BUSINESS COMBINATIONS (Pro Forma Information) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Starbuck Bancshares, Inc [Member]
Business Acquisition [Line Items]
Total revenues (net interest income plus non-interest income)	$ 455,427	$ 430,984
Net income	$ 86,255	$ 87,031
Earnings per share - basic (usd per share)	$ 2.56	$ 2.67
Earnings per share - diluted (usd per share)	$ 2.55	$ 2.67
Siuslaw Financial Group, Inc [Member]
Business Acquisition [Line Items]
Total revenues (net interest income plus non-interest income)	$ 308,153	$ 254,212
Net income	$ 44,484	$ 58,703
Earnings per share - basic (usd per share)	$ 1.85	$ 2.84
Earnings per share - diluted (usd per share)	$ 1.85	$ 2.83

BUSINESS COMBINATIONS BUSINES61

BUSINESS COMBINATIONS BUSINESS COMBINATIONS (Schedule of Acquisition Related Costs) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Acquisition related costs	$ 26,110	$ 4,325	$ 550
Six Oregon Branches [Member]
Business Acquisition [Line Items]
Acquisition related costs	0	1,784	550
Siuslaw Financial Group, Inc [Member]
Business Acquisition [Line Items]
Acquisition related costs	2,000	748	0
Starbuck Bancshares, Inc [Member]
Business Acquisition [Line Items]
Acquisition related costs	24,110	1,793	0
Salary and Employee Benefits [Member]
Business Acquisition [Line Items]
Acquisition related costs	6,577	0	0
Occupancy and Equipment [Member]
Business Acquisition [Line Items]
Acquisition related costs	1,031	105	0
Advertising and Marketing [Member]
Business Acquisition [Line Items]
Acquisition related costs	527	327	0
Information and Computer Data Services [Member]
Business Acquisition [Line Items]
Acquisition related costs	2,875	334	0
Payment and Card Processing Expenses [Member]
Business Acquisition [Line Items]
Acquisition related costs	28	185	0
Professional Services [Member]
Business Acquisition [Line Items]
Acquisition related costs	11,169	2,953	550
Miscellaneous Other Noninterest Expense [Member]
Business Acquisition [Line Items]
Acquisition related costs	$ 3,903	$ 421	$ 0

SECURITIES (Schedule of Securit

SECURITIES (Schedule of Securities) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Trading:
Trading Securities, Amortized Cost	$ 39,344	$ 47,480
Trading Securities, Fair Value	34,134	40,258
Available-for-Sale:
Available-for-sale Securities, Amortized Cost	1,139,740	411,424
Gross Unrealized Gains	5,188	1,812
Gross Unrealized Losses	(6,355)	(2,215)
Securities—available-for-sale	1,138,573	411,021
Held-to-Maturity:
Held-to-maturity Securities, Amortized Cost	220,666	131,258
Gross Unrealized Gains	6,477	6,424
Gross Unrealized Losses	(516)	(74)
Held-to-maturity Securities, Fair Value	226,627	137,608
U.S. Government and agency obligations
Trading:
Trading Securities, Amortized Cost	1,230	1,340
Trading Securities, Fair Value	1,368	1,505
Available-for-Sale:
Available-for-sale Securities, Amortized Cost	30,211	29,973
Gross Unrealized Gains	213	8
Gross Unrealized Losses	(193)	(211)
Securities—available-for-sale	30,231	29,770
Held-to-Maturity:
Held-to-maturity Securities, Amortized Cost	1,106	2,146
Gross Unrealized Gains	5	0
Gross Unrealized Losses	0	(19)
Held-to-maturity Securities, Fair Value	1,111	2,127
Municipal bonds
Trading:
Trading Securities, Amortized Cost	332	1,405
Trading Securities, Fair Value	341	1,440
Available-for-Sale:
Available-for-sale Securities, Amortized Cost	142,898	49,959
Gross Unrealized Gains	853	190
Gross Unrealized Losses	(432)	(121)
Securities—available-for-sale	143,319	50,028
Held-to-Maturity:
Held-to-maturity Securities, Amortized Cost	162,778	119,951
Gross Unrealized Gains	6,219	6,319
Gross Unrealized Losses	(191)	(48)
Held-to-maturity Securities, Fair Value	168,806	126,222
Corporate bonds
Trading:
Trading Securities, Amortized Cost	25,063	27,995
Trading Securities, Fair Value	18,699	19,118
Available-for-Sale:
Available-for-sale Securities, Amortized Cost	15,937	5,000
Gross Unrealized Gains	56	18
Gross Unrealized Losses	(12)	0
Securities—available-for-sale	15,981	5,018
Held-to-Maturity:
Held-to-maturity Securities, Amortized Cost	4,273	1,800
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Held-to-maturity Securities, Fair Value	4,273	1,800
Mortgage-backed or related securities
Trading:
Trading Securities, Amortized Cost	12,705	16,726
Trading Securities, Fair Value	13,663	18,136
Available-for-Sale:
Available-for-sale Securities, Amortized Cost	919,318	300,979
Gross Unrealized Gains	4,056	1,429
Gross Unrealized Losses	(5,115)	(1,598)
Securities—available-for-sale	918,259	300,810
Held-to-Maturity:
Held-to-maturity Securities, Amortized Cost	52,509	7,361
Gross Unrealized Gains	253	105
Gross Unrealized Losses	(325)	(7)
Held-to-maturity Securities, Fair Value	52,437	7,459
Asset-backed securities
Available-for-Sale:
Available-for-sale Securities, Amortized Cost	31,288	25,513
Gross Unrealized Gains	0	167
Gross Unrealized Losses	(603)	(285)
Securities—available-for-sale	30,685	25,395
Equity securities
Trading:
Trading Securities, Amortized Cost	14	14
Trading Securities, Fair Value	63	$ 59
Available-for-Sale:
Available-for-sale Securities, Amortized Cost	88
Gross Unrealized Gains	10
Gross Unrealized Losses	0
Securities—available-for-sale	$ 98

SECURITIES (Securities with Con

SECURITIES (Securities with Continuous Loss Position) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Available-for-Sale:
Less than 12 Months, Fair Value	$ 637,744	$ 123,351
Less than 12 Months, Unrealized Losses	(5,270)	(355)
12 Months or More, Fair Value	89,748	134,007
12 Months or More, Unrealized Losses	(1,085)	(1,860)
Total Fair Value	727,492	257,358
Total Unrealized Losses	(6,355)	(2,215)
Held-to-Maturity:
Less Than 12 Months, Fair Value	63,038	10,839
Less Than 12 Months, Unrealized Losses	(511)	(51)
12 Months or More, Fair Value	509	1,719
12 Months or More, Unrealized Losses	(5)	(23)
Total Fair Value	63,547	12,558
Total Unrealized Losses	(516)	(74)
U.S. Government and agency obligations
Available-for-Sale:
Less than 12 Months, Fair Value	8,707	15,983
Less than 12 Months, Unrealized Losses	(97)	(58)
12 Months or More, Fair Value	10,489	9,847
12 Months or More, Unrealized Losses	(96)	(153)
Total Fair Value	19,196	25,830
Total Unrealized Losses	(193)	(211)
Held-to-Maturity:
Less Than 12 Months, Fair Value		0
Less Than 12 Months, Unrealized Losses		0
12 Months or More, Fair Value		1,127
12 Months or More, Unrealized Losses		(19)
Total Fair Value		1,127
Total Unrealized Losses		(19)
Municipal bonds
Available-for-Sale:
Less than 12 Months, Fair Value	69,848	16,322
Less than 12 Months, Unrealized Losses	(426)	(61)
12 Months or More, Fair Value	905	7,129
12 Months or More, Unrealized Losses	(6)	(60)
Total Fair Value	70,753	23,451
Total Unrealized Losses	(432)	(121)
Held-to-Maturity:
Less Than 12 Months, Fair Value	28,545	9,821
Less Than 12 Months, Unrealized Losses	(188)	(44)
12 Months or More, Fair Value	254	592
12 Months or More, Unrealized Losses	(3)	(4)
Total Fair Value	28,799	10,413
Total Unrealized Losses	(191)	(48)
Corporate bonds
Available-for-Sale:
Less than 12 Months, Fair Value	5,153
Less than 12 Months, Unrealized Losses	(12)
12 Months or More, Fair Value	0
12 Months or More, Unrealized Losses	0
Total Fair Value	5,153
Total Unrealized Losses	(12)
Held-to-Maturity:
Less Than 12 Months, Fair Value	0
Less Than 12 Months, Unrealized Losses	0
12 Months or More, Fair Value	0
12 Months or More, Unrealized Losses	0
Total Fair Value	0
Total Unrealized Losses	0
Mortgage-backed or related securities
Available-for-Sale:
Less than 12 Months, Fair Value	533,143	91,046
Less than 12 Months, Unrealized Losses	(4,380)	(236)
12 Months or More, Fair Value	68,562	107,266
12 Months or More, Unrealized Losses	(735)	(1,362)
Total Fair Value	601,705	198,312
Total Unrealized Losses	(5,115)	(1,598)
Held-to-Maturity:
Less Than 12 Months, Fair Value	34,493	1,018
Less Than 12 Months, Unrealized Losses	(323)	(7)
12 Months or More, Fair Value	255	0
12 Months or More, Unrealized Losses	(2)	0
Total Fair Value	34,748	1,018
Total Unrealized Losses	(325)	(7)
Asset-backed securities
Available-for-Sale:
Less than 12 Months, Fair Value	20,893	0
Less than 12 Months, Unrealized Losses	(355)	0
12 Months or More, Fair Value	9,792	9,765
12 Months or More, Unrealized Losses	(248)	(285)
Total Fair Value	30,685	9,765
Total Unrealized Losses	$ (603)	$ (285)

SECURITIES (Securities Debt Mat

SECURITIES (Securities Debt Maturities) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Amortized Cost
Maturing in one year or less	$ 0
Maturing after one year through five years	8,790
Maturing after five years through ten years	3,480
Maturing after ten years through twenty years	1,997
Maturing after twenty years	25,063
Total with Maturity Date	39,330
Equity securities	14
Trading Securities, Cost	39,344	$ 47,480
Fair Value
Maturing in one year or less	0
Maturing after one year through five years	9,361
Maturing after five years through ten years	3,823
Maturing after ten years through twenty years	2,188
Maturing after twenty years	18,699
Total with Maturity Date	34,071
Equity securities	63
Trading Securities, Fair Value	34,134	40,258
Amortized Cost
Maturing in one year or less	12,522
Maturing after one year through five years	278,205
Maturing after five years through ten years	185,919
Maturing after ten years through twenty years	338,069
Maturing after twenty years	324,937
Total with Maturity Date	1,139,652
Equity securities	88
Available-for-sale Securities, Amortized Cost	1,139,740	411,424
Fair Value
Maturing in one year or less	12,477
Maturing after one year through five years	277,056
Maturing after five years through ten years	184,948
Maturing after ten years through twenty years	338,362
Maturing after twenty years	325,632
Total with Maturity Date	1,138,475
Equity securities	98
Fair Value	1,138,573	411,021
Amortized Cost
Maturing in one year or less	4,986
Maturing after one year through five years	13,707
Maturing after five years through ten years	83,478
Maturing after ten years through twenty years	99,614
Maturing after twenty years	18,881
Held-to-maturity Securities	220,666	131,258
Fair Value
Maturing in one year or less	5,035
Maturing after one year through five years	13,810
Maturing after five years through ten years	84,158
Maturing after ten years through twenty years	104,460
Maturing after twenty years	19,164
Held-to-maturity Securities, Fair Value	$ 226,627	$ 137,608

SECURITIES (Securities Pledged)

SECURITIES (Securities Pledged) (Details) $ in Thousands	Dec. 31, 2015USD ($)
Pledged Financial Instruments, Not Separately Reported, Securities [Abstract]
State and local governments public deposits, carrying value	$ 204,894
Interest rate swap counterparties, carrying value	13,687
Repurchase transaction accounts, carrying value	110,140
Other, carrying value	1,970
Total pledged securities, carrying value	330,691
State and local governments public deposits, amortized cost	201,149
Interest rate swap counterparties, amortized cost	13,284
Repurchase transaction accounts, amortized cost	109,956
Other, amortized cost	1,895
Total pledged securities, amortized cost	326,284
State and local governments public deposits, fair value	210,422
Interest rate swap counterparties, fair value	13,687
Repurchase transaction accounts, fair value	110,146
Other, fair value	1,970
Total pledged securities, fair value	$ 336,225

SECURITIES (Textuals) (Details)

SECURITIES (Textuals) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)security	Dec. 31, 2014USD ($)security	Dec. 31, 2013USD ($)security
Trading Securities [Abstract]
Trading securites, proceeds from sale	$ 4,419	$ 2,387	$ 34,308
Trading Securities, Realized Gain (Loss)	(690)	1	1,545
Trading Securities, Realized Gain, Recoveries		1,000
Trading securities, OTTI charges	$ 0	$ 0	$ (409)
Trading securities, number of securities in nonaccrual status | security	0	0	0
Trading securities, unrealized holding gain		$ 2,000
Available-for-sale Securities [Abstract]
Available-for-sale securities, unrealized loss position, number of securities | security	242	94	114
Available-for-sale securities, sale proceeds	$ 232,600	$ 56,300	$ 103,300
Available-for-sale securities, OTTI charges	0	0	0
Available-for-sale securities, gross realized gain (loss)	$ 126	$ 41	$ (116)
Available-for-sale Securities, Number of Securities in Nonaccrual Status | security	0	0	0
Proceeds from Sale of Held-to-maturity Securities	$ 0	$ 0	$ 0
Held-to-maturity Securities [Abstract]
Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | security	32	25	36
Held-to-maturity securities, number of securities in nonaccrual status | security	0	0	0

LOANS RECEIVABLE AND THE ALLO67

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Loans by Type) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	$ 7,314,504	$ 3,831,034
Allowance for loan losses	78,008	75,907	$ 74,258
Total loans, net	$ 7,236,496	$ 3,755,127
Percent of total loans	100.00%	100.00%
Unearned loan fees in excess of unamortized costs	$ 5,500	$ (5,800)
Discount on acquired loans, net	43,700	148
Related party loans	7,900	8,600
Commerical real estate - owner-occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	$ 1,327,807	$ 546,783
Percent of total loans	18.20%	14.30%
Commerical real estate - investment properties [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	$ 1,765,353	$ 856,942
Percent of total loans	24.10%	22.30%
Multifamily real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	$ 472,976	$ 167,524
Allowance for loan losses	$ 4,195	$ 4,562	5,306
Percent of total loans	6.50%	4.40%
Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	$ 72,103	$ 17,337
Percent of total loans	1.00%	0.40%
Multifamily construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	$ 63,846	$ 60,193
Percent of total loans	0.90%	1.60%
One-to four-family construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	$ 278,469	$ 219,889
Percent of total loans	3.80%	5.70%
Land and land development - residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	$ 126,773	$ 102,435
Percent of total loans	1.70%	2.70%
Land and land development - commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	$ 33,179	$ 11,152
Percent of total loans	0.50%	0.30%
Commercial business [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	$ 1,207,944	$ 723,964
Allowance for loan losses	$ 13,856	$ 12,043	11,773
Percent of total loans	16.50%	18.90%
Agricultural business, including secured by farmland [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	$ 376,531	$ 238,499
Allowance for loan losses	$ 3,645	$ 3,821	2,841
Percent of total loans	5.10%	6.20%
One- to four-family residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	$ 952,633	$ 537,108
Allowance for loan losses	$ 4,732	$ 5,447	$ 11,486
Percent of total loans	13.00%	14.10%
Consumer secured by one- to four-family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	$ 478,420	$ 222,205
Percent of total loans	6.50%	5.80%
Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans outstanding	$ 158,470	$ 127,003
Percent of total loans	2.20%	3.30%

LOANS RECEIVABLE AND THE ALLO68

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Purchased Credit-Impaired Loans, Changes in Accretable Yield) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Receivables [Abstract]
Outstanding contractual unpaid balance of purchased credit-impaired loans	$ 83,400,000	$ 0
Carrying balance of purchased credit-impaired loans	58,600,000	0
Accretable Yield Movement Schedule [Roll Forward]
Balance, beginning of period	0	0
Additions	13,310,000	0
Accretion to interest income	2,202,000	0
Disposals	1,238,000	0
Reclassifications from non-accretable difference	505,000	0
Balance, end of period	10,375,000	$ 0
Non-accretable difference	$ 29,500,000

LOANS RECEIVABLE AND THE ALLO69

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Impaired Loans With and Without Specific Reserves) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	$ 41,295	$ 49,319
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	8,637	5,091
Recorded Investment	28,360	40,800
Related Allowance	2,307	3,092
Impaired Financing Receivable, Average Recorded Investment	36,340	45,440	$ 74,349
Interest Income Recognized	1,206	1,528	2,195
Commerical real estate - owner-occupied [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	1,465	1,598
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	0	966
Recorded Investment	1,416	582
Related Allowance	70	24
Impaired Financing Receivable, Average Recorded Investment	1,467	1,841	2,761
Interest Income Recognized	9	12	12
Commerical real estate - investment properties [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	8,740	6,458
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	2,503	30
Recorded Investment	5,846	6,023
Related Allowance	602	729
Impaired Financing Receivable, Average Recorded Investment	8,003	6,145	8,977
Interest Income Recognized	303	315	241
Multifamily real estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	359	786
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	0	0
Recorded Investment	357	786
Related Allowance	71	86
Impaired Financing Receivable, Average Recorded Investment	362	795	5,705
Interest Income Recognized	18	45	298
Commercial Construction [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	1,141
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	1,069
Recorded Investment	0
Related Allowance	0
One-to four-family construction [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	1,741	3,923
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	0	0
Recorded Investment	1,741	3,923
Related Allowance	161	640
Impaired Financing Receivable, Average Recorded Investment	1,463	2,655	5,870
Interest Income Recognized	114	118	239
Land and land development - residential [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	3,540	3,710
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	750	1,275
Recorded Investment	1,634	1,280
Related Allowance	444	346
Impaired Financing Receivable, Average Recorded Investment	2,406	2,872	6,053
Interest Income Recognized	49	89	221
Land and land development - commercial [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	1,628
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	$ 1,027
Recorded Investment
Related Allowance	$ 0
Impaired Financing Receivable, Average Recorded Investment	931	0	0
Interest Income Recognized	0	0	0
Commercial business [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	2,266	1,502
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	538	0
Recorded Investment	1,184	1,276
Related Allowance	150	128
Impaired Financing Receivable, Average Recorded Investment	1,667	1,328	2,236
Interest Income Recognized	35	41	59
Agricultural business, including secured by farmland [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	1,309	1,597
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	544	744
Recorded Investment	697	854
Related Allowance	43	26
Impaired Financing Receivable, Average Recorded Investment	1,143	1,866	110
Interest Income Recognized	19	0	8
One- to four-family residential [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	17,897	27,855
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	2,206	1,865
Recorded Investment	14,418	24,529
Related Allowance	736	1,032
Impaired Financing Receivable, Average Recorded Investment	17,770	26,093	40,557
Interest Income Recognized	630	870	1,063
Consumer secured by one- to four-family [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	776	1,256
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	0	73
Recorded Investment	716	1,077
Related Allowance	23	75
Impaired Financing Receivable, Average Recorded Investment	736	1,248	1,403
Interest Income Recognized	11	19	25
Consumer Loan [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Unpaid Principal Balance	433	634
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	0	138
Recorded Investment	351	470
Related Allowance	7	6
Impaired Financing Receivable, Average Recorded Investment	392	597	677
Interest Income Recognized	$ 18	$ 19	$ 29

LOANS RECEIVABLE AND THE ALLO70

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Troubled Debt Restructuring) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Troubled Debt Restructurings [Line Items]
Accrual Status	$ 21,777	$ 29,154
Nonaccrual Status	2,319	2,349
Total TDRs	24,096	31,503
Financing Receivable, Modifications, Commitments to Advance Funds	237	2,095
Commerical real estate - owner-occupied [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Accrual Status	181	183
Nonaccrual Status	104	109
Total TDRs	285	292
Commerical real estate - investment properties [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Accrual Status	5,834	6,021
Nonaccrual Status	13	32
Total TDRs	5,847	6,053
Multifamily real estate [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Accrual Status	357	786
Nonaccrual Status	0	0
Total TDRs	357	786
One-to four-family construction [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Accrual Status	1,741	3,923
Nonaccrual Status	0	0
Total TDRs	1,741	3,923
Land and land development - residential [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Accrual Status	1,151	1,279
Nonaccrual Status	483	525
Total TDRs	1,634	1,804
Commercial business [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Accrual Status	624	739
Nonaccrual Status	0	87
Total TDRs	624	826
Agricultural business, including secured by farmland [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Accrual Status	545	0
Nonaccrual Status	277	0
Total TDRs	822	0
One- to four-family residential [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Accrual Status	11,025	15,793
Nonaccrual Status	1,428	1,363
Total TDRs	12,453	17,156
Consumer secured by one- to four-family [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Accrual Status	147	233
Nonaccrual Status	14	117
Total TDRs	161	350
Consumer Loan [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Accrual Status	172	197
Nonaccrual Status	0	116
Total TDRs	$ 172	$ 313

LOANS RECEIVABLE AND THE ALLO71

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Newly Restructured Loans) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)contract	Dec. 31, 2014USD ($)contract
Financing Receivable, Troubled Debt Restructurings [Line Items]
Number of Contracts | contract	7	17
Pre-Modification Outstanding Recorded Investment	$ 2,555	$ 3,370
Post-Modification Outstanding Recorded Investment	$ 1,736	$ 3,327
Commerical real estate - owner-occupied [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Number of Contracts | contract	0	1
Pre-Modification Outstanding Recorded Investment	$ 0	$ 203
Post-Modification Outstanding Recorded Investment	$ 0	$ 203
One-to four-family construction [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Number of Contracts | contract	0	10
Pre-Modification Outstanding Recorded Investment	$ 0	$ 2,153
Post-Modification Outstanding Recorded Investment	$ 0	$ 2,153
Land and land development - residential [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Number of Contracts | contract	2	0
Pre-Modification Outstanding Recorded Investment	$ 1,302	$ 0
Post-Modification Outstanding Recorded Investment	$ 483	$ 0
Commercial business [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Number of Contracts | contract	0	1
Pre-Modification Outstanding Recorded Investment	$ 0	$ 100
Post-Modification Outstanding Recorded Investment	$ 0	$ 100
Agricultural business, including secured by farmland [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Number of Contracts | contract	3	0
Pre-Modification Outstanding Recorded Investment	$ 822	$ 0
Post-Modification Outstanding Recorded Investment	$ 822	$ 0
One- to four-family residential [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Number of Contracts | contract	2	4
Pre-Modification Outstanding Recorded Investment	$ 431	$ 905
Post-Modification Outstanding Recorded Investment	$ 431	$ 862
Consumer Loan [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Number of Contracts | contract	0	1
Pre-Modification Outstanding Recorded Investment	$ 0	$ 9
Post-Modification Outstanding Recorded Investment	$ 0	$ 9

LOANS RECEIVABLE AND THE ALLO72

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Troubled Debt Restructuring Which Incurred Payment Default) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)loan	Dec. 31, 2014USD ($)loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDRs Which Incurred Payment Default, Number of Loans | loan	3	0
TDRs Which Incurred a Payment Default | $	$ 664	$ 0
Agricultural Business [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDRs Which Incurred Payment Default, Number of Loans | loan	2	0
TDRs Which Incurred a Payment Default | $	$ 277	$ 0
One- to four-family residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDRs Which Incurred Payment Default, Number of Loans | loan	1	0
TDRs Which Incurred a Payment Default | $	$ 387	$ 0

LOANS RECEIVABLE AND THE ALLO73

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Risk-Rate and Non-Risk Rated Loans by Grade and Other Characteristic) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	$ 7,314,504	$ 3,831,034
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	3,093,160	1,403,725
Multifamily Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	472,976	167,524
Construction and Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	574,370	411,006
Commercial business [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	1,207,944	723,964
Agricultural Business [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	376,531	238,499
One- to four-family residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	952,633	537,108
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	636,890	349,208
Pass (Risk Ratings 1-5) [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	7,148,698	3,734,251
Pass (Risk Ratings 1-5) [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	3,022,281	1,375,885
Pass (Risk Ratings 1-5) [Member] | Multifamily Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	468,467	166,712
Pass (Risk Ratings 1-5) [Member] | Construction and Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	558,425	395,356
Pass (Risk Ratings 1-5) [Member] | Commercial business [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	1,167,933	691,143
Pass (Risk Ratings 1-5) [Member] | Small Credit-Scored Business Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	150,000	115,000
Pass (Risk Ratings 1-5) [Member] | Agricultural Business [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	354,760	234,101
Pass (Risk Ratings 1-5) [Member] | One- to four-family residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	943,098	524,598
Pass (Risk Ratings 1-5) [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	633,734	346,456
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	77,632	32,428
Special Mention [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	30,928	3,717
Special Mention [Member] | Multifamily Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	138	0
Special Mention [Member] | Construction and Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	2,386	0
Special Mention [Member] | Commercial business [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	25,286	27,453
Special Mention [Member] | Agricultural Business [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	17,526	1,055
Special Mention [Member] | One- to four-family residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	1,346	63
Special Mention [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	22	140
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	88,164	64,344
Substandard [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	39,951	24,123
Substandard [Member] | Multifamily Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	4,371	812
Substandard [Member] | Construction and Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	13,559	15,650
Substandard [Member] | Commercial business [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	14,725	5,368
Substandard [Member] | Agricultural Business [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	4,245	3,343
Substandard [Member] | One- to four-family residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	8,189	12,447
Substandard [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	3,124	2,601
Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	10	11
Doubtful [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0	0
Doubtful [Member] | Multifamily Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0	0
Doubtful [Member] | Construction and Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0	0
Doubtful [Member] | Commercial business [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0	0
Doubtful [Member] | Agricultural Business [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0	0
Doubtful [Member] | One- to four-family residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0	0
Doubtful [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	10	11
Unlikely to be Collected Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0		$ 0
Unlikely to be Collected Financing Receivable [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0		0
Unlikely to be Collected Financing Receivable [Member] | Multifamily Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0		0
Unlikely to be Collected Financing Receivable [Member] | Construction and Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0		0
Unlikely to be Collected Financing Receivable [Member] | Commercial business [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0		0
Unlikely to be Collected Financing Receivable [Member] | Agricultural Business [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0		0
Unlikely to be Collected Financing Receivable [Member] | One- to four-family residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0		0
Unlikely to be Collected Financing Receivable [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0		$ 0
Performing loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	7,240,682	3,814,298
Performing loans [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	3,048,424	1,402,328
Performing loans [Member] | Multifamily Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	470,982	167,524
Performing loans [Member] | Construction and Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	566,460	409,731
Performing loans [Member] | Commercial business [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	1,198,475	723,427
Performing loans [Member] | Agricultural Business [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	374,305	236,902
Performing loans [Member] | One- to four-family residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	945,968	526,506
Performing loans [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	636,068	347,880
Nonperforming loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	15,222	16,736
Nonperforming loans [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	3,751	1,397
Nonperforming loans [Member] | Multifamily Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	0	0
Nonperforming loans [Member] | Construction and Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	2,260	1,275
Nonperforming loans [Member] | Commercial business [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	2,167	537
Nonperforming loans [Member] | Agricultural Business [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	697	1,597
Nonperforming loans [Member] | One- to four-family residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	5,599	10,602
Nonperforming loans [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	748	$ 1,328
Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	58,600
Receivables Acquired with Deteriorated Credit Quality [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	40,985
Receivables Acquired with Deteriorated Credit Quality [Member] | Multifamily Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	1,994
Receivables Acquired with Deteriorated Credit Quality [Member] | Construction and Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	5,650
Receivables Acquired with Deteriorated Credit Quality [Member] | Commercial business [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	7,302
Receivables Acquired with Deteriorated Credit Quality [Member] | Agricultural Business [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	1,529
Receivables Acquired with Deteriorated Credit Quality [Member] | One- to four-family residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	1,066
Receivables Acquired with Deteriorated Credit Quality [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	74
Receivables Acquired with Deteriorated Credit Quality [Member] | Performing loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	58,600
Receivables Acquired with Deteriorated Credit Quality [Member] | Performing loans [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	40,985
Receivables Acquired with Deteriorated Credit Quality [Member] | Performing loans [Member] | Multifamily Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	1,994
Receivables Acquired with Deteriorated Credit Quality [Member] | Performing loans [Member] | Construction and Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	5,650
Receivables Acquired with Deteriorated Credit Quality [Member] | Performing loans [Member] | Commercial business [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	7,302
Receivables Acquired with Deteriorated Credit Quality [Member] | Performing loans [Member] | Agricultural Business [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	1,529
Receivables Acquired with Deteriorated Credit Quality [Member] | Performing loans [Member] | One- to four-family residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	1,066
Receivables Acquired with Deteriorated Credit Quality [Member] | Performing loans [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans receivable	$ 74

LOANS RECEIVABLE AND THE ALLO74

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Age Analysis of Company's Past Due Loans) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	$ 24,733	$ 18,845
Carrying balance of purchased credit-impaired loans	58,600	0
Current	7,231,171	3,812,189
Loans receivable	7,314,504	3,831,034
Loans 90 Days or More Past Due and Accruing	952	2,175
Financing Receivable, Recorded Investment, Nonaccrual Status	14,270	14,562
Commerical real estate - owner-occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	5,005	1,984
Carrying balance of purchased credit-impaired loans	24,261	0
Current	1,298,541	544,799
Loans receivable	1,327,807	546,783
Loans 90 Days or More Past Due and Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	1,235	1,100
Commerical real estate - investment properties [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	4,398	639
Carrying balance of purchased credit-impaired loans	16,724	0
Current	1,744,231	856,303
Loans receivable	1,765,353	856,942
Loans 90 Days or More Past Due and Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	2,516	32
Multifamily real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	4	0
Carrying balance of purchased credit-impaired loans	1,994	0
Current	470,978	167,524
Loans receivable	472,976	167,524
Loans 90 Days or More Past Due and Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	0	0
Commercial Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
Carrying balance of purchased credit-impaired loans	0	0
Current	72,103	17,337
Loans receivable	72,103	17,337
Loans 90 Days or More Past Due and Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	0	1,275
Multifamily construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	784	0
Carrying balance of purchased credit-impaired loans	0	0
Current	63,062	60,193
Loans receivable	63,846	60,193
Loans 90 Days or More Past Due and Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	0	0
One-to four-family construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,686	840
Carrying balance of purchased credit-impaired loans	905	0
Current	274,878	219,049
Loans receivable	278,469	219,889
Loans 90 Days or More Past Due and Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	1,233	0
Land and land development - residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	747	1,509
Carrying balance of purchased credit-impaired loans	77	0
Current	125,949	100,926
Loans receivable	126,773	102,435
Loans 90 Days or More Past Due and Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	1,027	0
Land and land development - commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	96	0
Carrying balance of purchased credit-impaired loans	4,668	0
Current	28,415	11,152
Loans receivable	33,179	11,152
Loans 90 Days or More Past Due and Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	0	0
Commercial business [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	3,042	910
Carrying balance of purchased credit-impaired loans	7,302	0
Current	1,197,600	723,054
Loans receivable	1,207,944	723,964
Loans 90 Days or More Past Due and Accruing	8	0
Financing Receivable, Recorded Investment, Nonaccrual Status	2,159	537
Agricultural business, including secured by farmland [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,330	1,807
Carrying balance of purchased credit-impaired loans	1,529	0
Current	373,672	236,692
Loans receivable	376,531	238,499
Loans 90 Days or More Past Due and Accruing	0	0
Financing Receivable, Recorded Investment, Nonaccrual Status	697	1,597
One- to four-family residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	5,304	10,026
Carrying balance of purchased credit-impaired loans	1,066	0
Current	946,263	527,082
Loans receivable	952,633	537,108
Loans 90 Days or More Past Due and Accruing	899	2,095
Financing Receivable, Recorded Investment, Nonaccrual Status	4,700	8,834
Exactly 30 Days Past Due, Not Included in Past Due Loans	4,000	8,000
Consumer secured by one- to four-family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	563	258
Carrying balance of purchased credit-impaired loans	40	0
Current	477,817	221,947
Loans receivable	478,420	222,205
Loans 90 Days or More Past Due and Accruing	4	80
Financing Receivable, Recorded Investment, Nonaccrual Status	565	1,187
Consumer Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	774	872
Carrying balance of purchased credit-impaired loans	34	0
Current	157,662	126,131
Loans receivable	158,470	127,003
Loans 90 Days or More Past Due and Accruing	41	0
Financing Receivable, Recorded Investment, Nonaccrual Status	138	0
30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	12,725	5,037
30 to 59 Days Past Due [Member] | Commerical real estate - owner-occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	3,981	0
30 to 59 Days Past Due [Member] | Commerical real estate - investment properties [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,763	639
30 to 59 Days Past Due [Member] | Multifamily real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	4	0
30 to 59 Days Past Due [Member] | Commercial Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
30 to 59 Days Past Due [Member] | Multifamily construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	771	0
30 to 59 Days Past Due [Member] | One-to four-family construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,466	840
30 to 59 Days Past Due [Member] | Land and land development - residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	759
30 to 59 Days Past Due [Member] | Land and land development - commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
30 to 59 Days Past Due [Member] | Commercial business [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,844	775
30 to 59 Days Past Due [Member] | Agricultural business, including secured by farmland [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	323	597
30 to 59 Days Past Due [Member] | One- to four-family residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	620	877
30 to 59 Days Past Due [Member] | Consumer secured by one- to four-family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	465	59
30 to 59 Days Past Due [Member] | Consumer Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	488	491
60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,591	4,256
60 to 89 Days Past Due [Member] | Commerical real estate - owner-occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	139	1,984
60 to 89 Days Past Due [Member] | Commerical real estate - investment properties [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	132	0
60 to 89 Days Past Due [Member] | Multifamily real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
60 to 89 Days Past Due [Member] | Commercial Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
60 to 89 Days Past Due [Member] | Multifamily construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	13	0
60 to 89 Days Past Due [Member] | One-to four-family construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	220	0
60 to 89 Days Past Due [Member] | Land and land development - residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
60 to 89 Days Past Due [Member] | Land and land development - commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	96	0
60 to 89 Days Past Due [Member] | Commercial business [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	174	35
60 to 89 Days Past Due [Member] | Agricultural business, including secured by farmland [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	729	466
60 to 89 Days Past Due [Member] | One- to four-family residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	873	1,623
60 to 89 Days Past Due [Member] | Consumer secured by one- to four-family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	60	60
60 to 89 Days Past Due [Member] | Consumer Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	155	88
90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	9,417	9,552
90 Days or More Past Due [Member] | Commerical real estate - owner-occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	885	0
90 Days or More Past Due [Member] | Commerical real estate - investment properties [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,503	0
90 Days or More Past Due [Member] | Multifamily real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
90 Days or More Past Due [Member] | Commercial Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
90 Days or More Past Due [Member] | Multifamily construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
90 Days or More Past Due [Member] | One-to four-family construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
90 Days or More Past Due [Member] | Land and land development - residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	747	750
90 Days or More Past Due [Member] | Land and land development - commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
90 Days or More Past Due [Member] | Commercial business [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,024	100
90 Days or More Past Due [Member] | Agricultural business, including secured by farmland [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	278	744
90 Days or More Past Due [Member] | One- to four-family residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	3,811	7,526
90 Days or More Past Due [Member] | Consumer secured by one- to four-family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	38	139
90 Days or More Past Due [Member] | Consumer Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	$ 131	$ 293

LOANS RECEIVABLE AND THE ALLO75

LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Allowance for Credit Losses) (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	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, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				$ 75,907				$ 74,258					$ 75,907	$ 74,258
Provision for loan losses	$ 0	$ 0	$ 0	0	$ 0	$ 0	$ 0	0	$ 0	$ 0	$ 0	$ 0	0	0	$ 0
Recoveries													6,960	6,993
Charge-offs													(4,859)	(5,344)
Ending balance	78,008				75,907				74,258				78,008	75,907	74,258
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment																$ 1,920	$ 2,966
Allowance collectively evaluated for impairment																76,033	72,941
Allowance for loan losses	78,008			75,907	75,907			74,258	74,258				75,907	74,258	74,258	78,008	75,907
Loans individually evaluated for impairment																28,816	34,446
Loans collectively evaluated for impairment																7,227,088	3,796,588
Loans receivable																7,314,504	3,831,034
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				18,784				16,759					18,784	16,759
Provision for loan losses													1,177	1,757
Recoveries													819	1,507
Charge-offs													(64)	(1,239)
Ending balance	20,716				18,784				16,759				20,716	18,784	16,759
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment																605	728
Allowance collectively evaluated for impairment																20,111	18,056
Allowance for loan losses	20,716			18,784	18,784			16,759	16,759				18,784	16,759	16,759	20,716	18,784
Loans individually evaluated for impairment																8,519	7,171
Loans collectively evaluated for impairment																3,043,656	1,396,554
Loans receivable																3,093,160	1,403,725
Multifamily Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				4,562				5,306					4,562	5,306
Provision for loan losses													(480)	(724)
Recoveries													113	0
Charge-offs													0	(20)
Ending balance	4,195				4,562				5,306				4,195	4,562	5,306
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment																71	86
Allowance collectively evaluated for impairment																4,124	4,476
Allowance for loan losses	4,195			4,562	4,562			5,306	5,306				4,562	5,306	5,306	4,195	4,562
Loans individually evaluated for impairment																357	786
Loans collectively evaluated for impairment																470,625	166,738
Loans receivable																472,976	167,524
Construction and Land [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				25,545				17,640					25,545	17,640
Provision for loan losses													666	6,336
Recoveries													1,811	1,776
Charge-offs													(891)	(207)
Ending balance	27,131				25,545				17,640				27,131	25,545	17,640
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment																418	986
Allowance collectively evaluated for impairment																26,713	24,559
Allowance for loan losses	27,131			25,545	25,545			17,640	17,640				25,545	17,640	17,640	27,131	25,545
Loans individually evaluated for impairment																4,669	6,477
Loans collectively evaluated for impairment																564,051	404,529
Loans receivable																574,370	411,006
Commercial business [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				12,043				11,773					12,043	11,773
Provision for loan losses													1,611	626
Recoveries													948	988
Charge-offs													(746)	(1,344)
Ending balance	13,856				12,043				11,773				13,856	12,043	11,773
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment																69	82
Allowance collectively evaluated for impairment																13,732	11,961
Allowance for loan losses	13,856			12,043	12,043			11,773	11,773				12,043	11,773	11,773	13,856	12,043
Loans individually evaluated for impairment																2,223	739
Loans collectively evaluated for impairment																1,198,419	723,225
Loans receivable																1,207,944	723,964
Agricultural Business [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				3,821				2,841					3,821	2,841
Provision for loan losses													(878)	(417)
Recoveries													1,927	1,576
Charge-offs													(1,225)	(179)
Ending balance	3,645				3,821				2,841				3,645	3,821	2,841
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment																0	0
Allowance collectively evaluated for impairment																3,645	3,821
Allowance for loan losses	3,645			3,821	3,821			2,841	2,841				3,821	2,841	2,841	3,645	3,821
Loans individually evaluated for impairment																544	744
Loans collectively evaluated for impairment																374,458	237,755
Loans receivable																376,531	238,499
One- to four-family residential [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				5,447				11,486					5,447	11,486
Provision for loan losses													(1,068)	(5,772)
Recoveries													772	618
Charge-offs													(419)	(885)
Ending balance	4,732				5,447				11,486				4,732	5,447	11,486
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment																728	1,014
Allowance collectively evaluated for impairment																4,004	4,433
Allowance for loan losses	4,732			5,447	5,447			11,486	11,486				5,447	11,486	11,486	4,732	5,447
Loans individually evaluated for impairment																12,185	17,848
Loans collectively evaluated for impairment																939,382	519,260
Loans receivable																952,633	537,108
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				483				1,335					483	1,335
Provision for loan losses													1,363	90
Recoveries													570	528
Charge-offs													(1,514)	(1,470)
Ending balance	902				483				1,335				902	483	1,335
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment																29	70
Allowance collectively evaluated for impairment																873	413
Allowance for loan losses	902			483	483			1,335	1,335				483	1,335	1,335	902	483
Loans individually evaluated for impairment																319	681
Loans collectively evaluated for impairment																636,497	348,527
Loans receivable																636,890	349,208
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				5,222				7,118					5,222	7,118
Provision for loan losses													(2,391)	(1,896)
Recoveries													0	0
Charge-offs													0	0
Ending balance	2,831				5,222				7,118				2,831	5,222	7,118
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment																0	0
Allowance collectively evaluated for impairment																2,831	5,222
Allowance for loan losses	2,831			$ 5,222	$ 5,222			$ 7,118	$ 7,118				5,222	$ 7,118	$ 7,118	2,831	5,222
Loans individually evaluated for impairment																0	0
Loans collectively evaluated for impairment																0	0
Loans receivable																0	$ 0
Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Ending balance	55												55
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for loan losses	55												55			55
Loans receivable																58,600
Receivables Acquired with Deteriorated Credit Quality [Member] | Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Ending balance	0												0
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for loan losses	0												0			0
Loans receivable																40,985
Receivables Acquired with Deteriorated Credit Quality [Member] | Multifamily Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Ending balance	0												0
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for loan losses	0												0			0
Loans receivable																1,994
Receivables Acquired with Deteriorated Credit Quality [Member] | Construction and Land [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Ending balance	0												0
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for loan losses	0												0			0
Loans receivable																5,650
Receivables Acquired with Deteriorated Credit Quality [Member] | Commercial business [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Ending balance	55												55
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for loan losses	55												55			55
Loans receivable																7,302
Receivables Acquired with Deteriorated Credit Quality [Member] | Agricultural Business [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Ending balance	0												0
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for loan losses	0												0			0
Loans receivable																1,529
Receivables Acquired with Deteriorated Credit Quality [Member] | One- to four-family residential [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Ending balance	0												0
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for loan losses	0												0			0
Loans receivable																1,066
Receivables Acquired with Deteriorated Credit Quality [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Ending balance	0												0
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for loan losses	0												0			0
Loans receivable																74
Receivables Acquired with Deteriorated Credit Quality [Member] | Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Ending balance	0												0
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance for loan losses	$ 0												$ 0			0
Loans receivable																$ 0

REAL ESTATE OWNED, HELD FOR S76

REAL ESTATE OWNED, HELD FOR SALE, NET (REO Rollforward) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Real Estate Owned [Roll Forward]
Balance, beginning of period	$ 3,352	$ 4,044	$ 15,778
Additions from loan foreclosures	4,351	3,264	3,166
Additions from capitalized costs	298	30	348
Real Estate Owned, Additions from Acquisitions	8,231	0	0
Proceeds from dispositions of REO	(4,740)	(4,923)	(16,944)
Gain on sale of REO	351	973	2,481
Valuation adjustments in the period	(216)	(36)	(785)
Balance, end of period	$ 11,627	$ 3,352	$ 4,044

PROPERTY AND EQUIPMENT, NET (De

PROPERTY AND EQUIPMENT, NET (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Land	$ 38,992	$ 21,969
Buildings and leasehold improvements	160,075	98,901
Furniture and equipment	79,018	72,152
Property and equipment, gross	278,085	193,022
Less accumulated depreciation	(110,481)	(101,837)
Property and equipment, net	$ 167,604	$ 91,185

PROPERTY AND EQUIPMENT, NET (Op

PROPERTY AND EQUIPMENT, NET (Operating Lease Commitments) (Details) $ in Millions	Dec. 31, 2015USD ($)
Property, Plant and Equipment [Abstract]
2,016	$ 14.3
2,017	12.9
2,018	10.7
2,019	7.8
2,020	6.6
Thereafter	23
Total	$ 75.3

PROPERTY AND EQUIPMENT, NET PRO

PROPERTY AND EQUIPMENT, NET PROPERTY AND EQUIPMENT, NET (Textual) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 9,957	$ 8,064	$ 7,457
Rental expense	$ 10,200	$ 7,600	$ 7,300

DEPOSITS (Deposit Liabilities)

DEPOSITS (Deposit Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deposit Liabilities [Line Items]
Non-interest-bearing checking	$ 2,619,618	$ 1,298,866
Interest-bearing checking	1,159,846	439,480
Regular savings accounts	1,284,642	901,142
Money market accounts	1,637,092	488,946
Total transaction and savings accounts	6,701,198	3,128,434
Time Deposits, $250,000 or less	1,168,495	633,345
Time Deposits, More than $250,000	185,375	137,171
Interest-bearing certificates	1,353,870	770,516
Total deposits	8,055,068	3,898,950
Included in total deposits:
Public fund transaction accounts	209,430	102,854
Public fund interest-bearing certificates	31,281	35,346
Total public deposits	240,711	138,200
Total brokered deposits	162,936	4,799
Related Party Deposit Liabilities	$ 6,600	$ 6,200

DEPOSITS (Maturities and Weight

DEPOSITS (Maturities and Weighted Average Interest Rates of Certificates of Deposit) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Maturities of Time Deposits [Abstract]
Maturing in one year or less	$ 985,193
Maturing after one year through two years	226,381
Maturing after two years through three years	88,184
Maturing after three years through four years	24,981
Maturing after four years through five years	25,917
Maturing after five years	3,214
Total certificates of deposit	$ 1,353,870	$ 770,516
Weighted Average Rate [Abstract]
Maturing in one year or less	0.48%
Maturing after one year through two years	0.88%
Maturing after two years through three years	1.05%
Maturing after three years through four years	1.17%
Maturing after four years through five years	1.26%
Maturing after five years	1.10%
Total certificates of deposits	0.61%

ADVANCES FROM FEDERAL HOME LO82

ADVANCES FROM FEDERAL HOME LOAN BANK OF DES MOINES (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Advances from Federal Home Loan Banks [Abstract]
Federal Home Loan Bank, advances, collateral pledged	$ 0	$ 0
Federal Home Loan Bank, Advances, Fiscal Year Maturity [Abstract]
Maturing in one year or less	107,600,000	32,000,000
Maturing after one year through three years	25,000,000	0
Maturing after three years through five years	0	0
Maturing after five years	188,000	196,000
Total FHLB advances, at par	132,788,000	32,196,000
Fair value adjustment	593,000	54,000
Total FHLB advances, carried at fair value	133,381,000	32,250,000
Federal Home Loan Bank, advances, maximum outstanding at any month end	221,600,000	105,500,000
Federal Home Loan Bank, advances, average balance outstanding	$ 45,000,000	$ 39,100,000
Federal Home Loan Bank, advances, average interest rate for year	0.69%	0.32%
Subsidiary, Banner Bank [Member]
Federal Home Loan Bank, Advances, Fiscal Year Maturity [Abstract]
Federal Home Loan Bank, advances, percentage of total assets to support credit line	35.00%
Federal Home Loan Bank, advances, maximum credit line	$ 1,768,000,000
Subsidiary, Islanders Bank [Member]
Federal Home Loan Bank, Advances, Fiscal Year Maturity [Abstract]
Federal Home Loan Bank, advances, percentage of total assets to support credit line	35.00%
Federal Home Loan Bank, advances, maximum credit line	$ 28,000,000

OTHER BORROWINGS (Schedule of O

OTHER BORROWINGS (Schedule of Other Borrowings) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Amount:
Total year-end outstanding	$ 98,325	$ 77,185
Repurchase Agreements [Member] | Retail repurchase agreements [Member]
Amount:
Maturing in one year or less	93,325	77,185
Maturing after one year through two years	0	0
Maturing after two years	5,000	0
Total year-end outstanding	$ 98,325	$ 77,185
Weighted Average Rate:
Maturing in one year or less, weighted average interest rate	0.19%	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	2.15%	0.00%
Total year-end outstanding, weighted average interest rate	0.29%	0.20%
Other Borrowings, Activity for Year [Abstract]
Average outstanding	$ 94,182	$ 83,965
Average outstanding, weighted average interest rate	0.22%	0.20%
Maximum outstanding at any month end	$ 102,474	$ 89,921

OTHER BORROWINGS (Textuals) (De

OTHER BORROWINGS (Textuals) (Details)	Dec. 31, 2015USD ($)agreement	Dec. 31, 2014USD ($)
Debt Instrument [Line Items]
Securities pledged to secure retail repurchase agreements	$ 110,140,000
Funds Borrowed Against Current Borrowing Capacity	98,325,000	$ 77,185,000
Repurchase Agreements [Member] | Retail repurchase agreements [Member]
Debt Instrument [Line Items]
Funds Borrowed Against Current Borrowing Capacity	$ 98,325,000	77,185,000
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%
Repurchase Agreements [Member] | Repurchase Agreement, Wholesale [Member]
Debt Instrument [Line Items]
Repurchase agreements, interest rate	2.15%
Number of repurchase agreements | agreement	1
Federal Reserve Bank Advances [Member] | Federal Reserve Bank of San Francisco [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity	$ 735,000,000
Funds Borrowed Against Current Borrowing Capacity	0	0
Subsidiary, Banner Bank [Member] | Federal Funds Purchased [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity	25,000,000
Line of credit, current	0	0
Subsidiary, Islanders Bank [Member] | Federal Funds Purchased [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity	5,000,000
Line of credit, current	$ 0	$ 0

JUNIOR SUBORDINATED DEBENTURE85

JUNIOR SUBORDINATED DEBENTURES AND MANDATORILY REDEEMABLE TRUST PREFERRED SECURITIES (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)subsidiary	Dec. 31, 2014USD ($)
Schedule of Trust Preferred Securities [Line Items]
Number of wholly-owned Grantor Trusts | subsidiary	9
Grantor trusts amount of tier one risk based capital	$ 1,057,597	$ 633,317
Debentures Subject to Mandatory Redemption [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	140,212
Fair value adjustment	(47,732)
Total TPS liability at fair value	$ 92,480
Current Interest Rate	2.76%
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	$ 88,300
Grantor trusts percentage of tier one risk based capital	14.00%
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	3.96%
Interest Rate Spread, Description	Three-month LIBOR
Interest Rate Spread	3.35%
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	3.51%
Interest Rate Spread, Description	Three-month LIBOR
Interest Rate Spread	2.90%
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	3.46%
Interest Rate Spread, Description	Three-month LIBOR
Interest Rate Spread	2.85%
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	2.18%
Interest Rate Spread, Description	Three-month LIBOR
Interest Rate Spread	1.57%
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	2.23%
Interest Rate Spread, Description	Three-month LIBOR
Interest Rate Spread	1.62%
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	1.99%
Interest Rate Spread, Description	Three-month LIBOR
Interest Rate Spread	1.38%
Debentures Subject to Mandatory Redemption [Member] | Siuslaw Statutory Trust One [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	$ 8,248
Current Interest Rate	3.31%
Interest Rate Spread, Description	Three-month LIBOR
Interest Rate Spread	2.70%
Debentures Subject to Mandatory Redemption [Member] | Greater Sacramento Bancorp Statutory Trust one [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	$ 4,124
Current Interest Rate	3.96%
Interest Rate Spread, Description	Three-month LIBOR
Interest Rate Spread	3.35%
Debentures Subject to Mandatory Redemption [Member] | Greater Sacramento Bancorp Statutory Trust Two [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	$ 4,124
Current Interest Rate	2.29%
Interest Rate Spread, Description	Three-month LIBOR
Interest Rate Spread	1.68%
Aggregate Liquidation Amount of Trust Preferred Securities [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	$ 136,000
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 Trust Preferred Securities [Member] | Siuslaw Statutory Trust One [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	8,000
Aggregate Liquidation Amount of Trust Preferred Securities [Member] | Greater Sacramento Bancorp Statutory Trust one [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	4,000
Aggregate Liquidation Amount of Trust Preferred Securities [Member] | Greater Sacramento Bancorp Statutory Trust Two [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	4,000
Aggregate Liquidation Amount of Common Capital Securities [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	4,212
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
Aggregate Liquidation Amount of Common Capital Securities [Member] | Siuslaw Statutory Trust One [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	248
Aggregate Liquidation Amount of Common Capital Securities [Member] | Greater Sacramento Bancorp Statutory Trust one [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	124
Aggregate Liquidation Amount of Common Capital Securities [Member] | Greater Sacramento Bancorp Statutory Trust Two [Member]
Schedule of Trust Preferred Securities [Line Items]
Total TPS liability at par	$ 124

INCOME TAXES (Components of Inc

INCOME TAXES (Components of Income Tax Expense (Benefit)) (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	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, 2015	Dec. 31, 2014	Dec. 31, 2013
Current Federal, State and Local, Tax Expense (Benefit) [Abstract]
Current Federal Tax Expense (Benefit)													$ 24,683	$ 23,411	$ 11,829
Current State and Local Tax Expense (Benefit)													1,399	1,444	292
Current													26,082	24,855	12,121
Deferred Federal, State and Local, Tax Expense (Benefit) [Abstract]
Deferred Federal Income Tax Expense (Benefit)													(3,310)	2,764	10,936
Deferred State and Local Income Tax Expense (Benefit)													(23)	(567)	1,132
Deferred													(3,333)	2,197	12,068
Increase (decrease) in valuation allowance													0	0	0
Provision for (benefit from) income taxes	$ 3,308	$ 6,642	$ 6,615	$ 6,184	$ 5,831	$ 7,284	$ 8,696	$ 5,241	$ 6,281	$ 6,459	$ 6,076	$ 5,373	$ 22,749	$ 27,052	$ 24,189

INCOME TAXES (Effective Income

INCOME TAXES (Effective Income Tax Rate Reconciliation) (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
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	(3.90%)	(2.60%)	(2.40%)
Investment in life insurance	(1.30%)	(0.80%)	(1.00%)
State income taxes, net of federal tax offset	1.10%	1.10%	1.20%
Tax credits	(1.60%)	(0.80%)	(0.90%)
Merger and acquisition costs	1.90%	0.70%	0.00%
Other	2.30%	0.70%	2.50%
Effective income tax rate	33.50%	33.30%	34.40%

INCOME TAXES (Schedule of Net D

INCOME TAXES (Schedule of Net Deferred Tax Asset ) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Loan loss and REO	$ 33,312	$ 26,536
Deferred compensation	19,253	9,223
Net operating loss carryforward	91,893	17,577
Federal and state tax credits	7,877	3,676
State net operating losses	8,692	1,009
Deferred Tax Asset, Loan Discount	13,412	(1,190)
Other	5,620	1,344
Total deferred tax assets	180,059	58,175
Deferred tax liabilities:
FHLB stock dividends	0	(4,805)
Depreciation	(1,103)	(4,479)
Deferred loan fees, servicing rights and loan origination costs	9,884	7,843
Intangibles	(13,320)	(975)
Financial instruments accounted for under fair value accounting	(17,112)	(15,611)
Unrealized (gain) loss on securities - available-for-sale	(1,475)	145
Total deferred tax liabilities	(42,894)	(33,568)
Deferred income tax asset	137,165	24,607
Valuation allowance	2,195	0
Deferred tax asset, net	$ 134,970	$ 24,607

INCOME TAXES (Textuals) (Detail

INCOME TAXES (Textuals) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Operating Loss Carryforwards [Line Items]
Operating loss carryforward, amount expected to be utilized on an annual basis	$ 6,900
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	262,500	$ 50,200
Operating loss carryforward, amount expected to be utilized on an annual basis	21,500
Tax basis bad debt reserves for which no income tax liability has been booked	5,400	5,400
Unrecognized deferred tax liability related to bad debt reserves	1,900
Refund due from amended federal income tax returns		9,800
Domestic Tax Authority [Member] | General Business Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Federal and state tax credit carryforwards	3,300	2,700
Domestic Tax Authority [Member] | Alternative Minimum Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Federal and state tax credit carryforwards	4,200	900
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	23,000	$ 21,200
Operating loss carryforwards, valuation allowance	2,200
Operating loss carryforward, amount expected to be utilized on an annual basis, valuation allowance	2,200
State and Local Jurisdiction [Member] | Alternative Minimum Tax Credit Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Federal and state tax credit carryforwards	$ 353

EMPLOYEE BENEFIT PLANS (Details

EMPLOYEE BENEFIT PLANS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Defined contribution plan expense	$ 2,800	$ 1,400	$ 1,031
Defined contribution plan, employer matching contribution percent	4.00%
Deferred compensation liability	$ 40,474	16,807
Carrying value of shares held in trust for stock related compensation plans	6,928	6,669
Cash surrender value of bank-owned life insurance policies	156,900	63,800
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	1,300	1,200	$ 1,497
Deferred compensation liability	39,000	14,200
Deferred Compensation Plans and Rabbi Trusts [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred compensation liability	8,400	8,200
Carrying value of shares held in trust for stock related compensation plans	6,900	6,700
Shares held in Treasury for future payment	$ 6,900	$ 6,700

STOCK-BASED COMPENSATION PLAN91

STOCK-BASED COMPENSATION PLANS (Stock Option Award Activity) (Details) - Stock Option Plans [Member] - Stock Options [Member] - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock Options Outstanding Shares:
Outstanding, beginning of the year	10,664	26,364	42,521
Granted	0	0	0
Exercised	0	0	0
Forfeited	(5,664)	(15,700)	(16,157)
Outstanding, end of the year	5,000	10,664	26,364	42,521
Outstanding at end of year, net of expected forfeitures, shares	0
Exercisable at end of year, shares	5,000
Stock Options Outstanding Weighted Average Exercise Price (in dollars per share):
Outstanding, beginning of the year	$ 206.03	$ 206.27	$ 173.98
Granted	0	0	0
Exercised	0	0	0
Forfeited	197.11	206.44	121.29
Outstanding, end of the year	216.16	$ 206.03	$ 206.27	$ 173.98
Outstanding end of year, net of expected forfeitures, weighted average exercise price	0
Exercisable end of year, weighted average exercise price	$ 216.16
Weighted Average Remaining Contractual Term, In Years:
Outstanding, end of year		1 year 10 months 24 days	1 year 6 months 29 days	1 year 9 months
Exercisable, end of year	1 year 6 months 29 days

STOCK-BASED COMPENSATION PLAN92

STOCK-BASED COMPENSATION PLANS (Financial Data Pertaining to Outstanding Stock Options) (Details) - Stock Option Plans [Member] - Stock Options [Member] - $216.16 [Member]	12 Months Ended
	Dec. 31, 2015$ / sharesshares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price	$ 216.16
Weighted Average Exercise Price of Option Shares Granted	$ 216.16
Number of Option Shares Granted | shares	5,000
Weighted Average Option Shares Vested and Exercisable | shares	5,000
Weighted Average Exercise Price of Option Shares Exercisable	$ 216.16
Remaining Contractual Life	1 year 6 months 29 days

STOCK-BASED COMPENSATION PLAN93

STOCK-BASED COMPENSATION PLANS (Restricted Stock and Restricted Stock Units Activity) (Details) - Restricted Stock and Restricted Stock Units [Member] - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Unvested Shares: [Roll Forward]
Unvested, Beginning Balance	195,106	164,492	107,851
Granted	155,183	90,181	98,891
Vested	(109,416)	(56,307)	(42,250)
Forfeited	(9,311)	(3,260)	0
Unvested, Ending Balance	231,562	195,106	164,492
Weighted Average Grant-Date Fair Value (in dollars per share):
Unvested, Beginning Balance	$ 32.83	$ 26.94	$ 20.59
Granted	45.59	40.07	30.81
Vested	30.28	24.81	19.85
Forfeited	39.07	31	0
Unvested, Ending Balance	$ 42.33	$ 32.83	$ 26.94

STOCK-BASED COMPENSATION PLAN94

STOCK-BASED COMPENSATION PLANS (Textuals) (Details) - USD ($)	12 Months Ended			20 Months Ended	44 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2015	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred compensation liability	$ 40,474,000	$ 16,807,000		$ 40,474,000	$ 40,474,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	3,500,000	$ 2,700,000	$ 1,471,000
Unrecognized compensation expense	$ 6,900,000			$ 6,900,000	$ 6,900,000
Unrecognized compensation expense, period for recognition	35 months
Stock Option Plans [Member] | Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized	68,571			68,571	68,571
Stock-based compensation expense	$ 0		$ 0
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	$ (103,000)	$ 89,000
2012 Restricted Stock and Incentive Bonus Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized	300,000			300,000	300,000
2012 Restricted Stock and Incentive Bonus Plan [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Shares granted in period					295,123
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period					181,305
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	113,818			113,818	113,818
Award termination period	10 years
2014 Omnibus Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized	900,000			900,000	900,000
2014 Omnibus Incentive Plan [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted in period				119,765
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period				9,352
2014 Omnibus Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted in period				7,331

PREFERRED STOCK AND RELATED W95

PREFERRED STOCK AND RELATED WARRANT (Details) - USD ($) $ / shares in Units, $ in Thousands	Nov. 21, 2008	Dec. 31, 2015	Dec. 31, 2014
Class of Stock [Line Items]
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
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

REGULATORY CAPITAL REQUIREMEN96

REGULATORY CAPITAL REQUIREMENTS (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Total capital to risk-weighted assets:
Actual	$ 1,139,554	$ 684,583
Actual, Ratio	13.63%	16.80%
Minimum for Capital Adequacy Purposes	$ 668,941	$ 326,071
Minimum for Capital Adequacy Purposes, Ratio	8.00%	8.00%
Tier 1 capital to risk-weighted assets:
Actual	$ 1,057,597	$ 633,317
Actual, Ratio	12.65%	15.54%
Minimum for Capital Adequacy Purposes	$ 501,706	$ 163,036
Minimum for Capital Adequacy Purposes, Ratio	6.00%	4.00%
Tier 1 common equity to risk-weighted assets:
Actual	$ 1,013,971
Actual, Ratio	12.13%
Minimum for Capital Adequacy Purposes	$ 376,279
Minimum for Capital Adequacy Purposes, Ratio	4.50%
Tier 1 leverage capital to average assets:
Actual	$ 1,057,597	$ 633,317
Actual, Ratio	11.06%	13.41%
Minimum for Capital Adequacy Purposes	$ 382,617	$ 188,885
Minimum for Capital Adequacy Purposes, Ratio	4.00%	4.00%
Banner Bank [Member]
Total capital to risk-weighted assets:
Actual	$ 1,030,601	$ 605,997
Actual, Ratio	12.61%	15.53%
Minimum for Capital Adequacy Purposes	$ 653,606	$ 312,220
Minimum for Capital Adequacy Purposes, Ratio	8.00%	8.00%
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions	$ 817,008	$ 390,274
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	$ 950,865	$ 556,897
Actual, Ratio	11.64%	14.27%
Minimum for Capital Adequacy Purposes	$ 490,205	$ 156,110
Minimum for Capital Adequacy Purposes, Ratio	6.00%	4.00%
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions	$ 653,606	$ 234,165
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	8.00%	6.00%
Tier 1 common equity to risk-weighted assets:
Actual	$ 950,865
Actual, Ratio	11.64%
Minimum for Capital Adequacy Purposes	$ 367,653
Minimum for Capital Adequacy Purposes, Ratio	4.50%
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions	$ 531,055
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	6.50%
Tier 1 leverage capital to average assets:
Actual	$ 950,865	$ 556,897
Actual, Ratio	10.23%	12.42%
Minimum for Capital Adequacy Purposes	$ 371,807	$ 179,304
Minimum for Capital Adequacy Purposes, Ratio	4.00%	4.00%
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions	$ 464,759	$ 224,130
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	$ 38,448	$ 36,590
Actual, Ratio	20.31%	19.92%
Minimum for Capital Adequacy Purposes	$ 15,146	$ 14,693
Minimum for Capital Adequacy Purposes, Ratio	8.00%	8.00%
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions	$ 18,932	$ 18,367
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	$ 36,227	$ 34,332
Actual, Ratio	19.14%	18.69%
Minimum for Capital Adequacy Purposes	$ 11,359	$ 7,347
Minimum for Capital Adequacy Purposes, Ratio	6.00%	4.00%
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions	$ 15,146	$ 11,020
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	8.00%	6.00%
Tier 1 common equity to risk-weighted assets:
Actual	$ 36,227
Actual, Ratio	19.14%
Minimum for Capital Adequacy Purposes	$ 8,520
Minimum for Capital Adequacy Purposes, Ratio	4.50%
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions	$ 12,306
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	6.50%
Tier 1 leverage capital to average assets:
Actual	$ 36,227	$ 34,332
Actual, Ratio	13.38%	13.68%
Minimum for Capital Adequacy Purposes	$ 10,826	$ 10,040
Minimum for Capital Adequacy Purposes, Ratio	4.00%	4.00%
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions	$ 13,533	$ 12,550
Minimum to be Categorized as Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	5.00%	5.00%

OTHER INTANGIBLE ASSETS AND M97

OTHER INTANGIBLE ASSETS AND MORTGAGE SERVICING RIGHTS (Finite-Lived Intangible Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 247,738	$ 0	$ 0	$ 0
Intangible Assets, Net (Including Goodwill)	284,500	2,831	2,449	$ 4,230
Goodwill, Acquired During Period	247,738	0	0
Finite-lived Intangible Assets [Roll Forward]
Acquired Intangible Assets (Including Goodwill)	285,133	2,372	160
Amortization	(3,164)	(1,990)	(1,941)
Balance, end of period	36,762
Goodwill, Other Changes	0
Finite-Lived Intangible Assets, Other Changes	(300)
Intangible Assets (including Goodwill), Other Changes	(300)
Core Deposit Intangibles [Member]
Finite-lived Intangible Assets [Roll Forward]
Balance, beginning of period	2,831	2,449	4,230
Additions through acquisition	37,395	2,372	160
Amortization	(3,164)	(1,990)	(1,941)
Balance, end of period	$ 36,762	$ 2,831	$ 2,449

OTHER INTANGIBLE ASSETS AND M98

OTHER INTANGIBLE ASSETS AND MORTGAGE SERVICING RIGHTS (Estimated Annual Amortization Expense) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Year Ended December 31, 2016	$ 7,061
Year Ended December 31, 2017	6,332
Year Ended December 31, 2018	5,610
Year Ended December 31, 2019	4,889
Thereafter	12,870
Net carrying amount	36,762
Core Deposit Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Net carrying amount	$ 36,762	$ 2,831	$ 2,449	$ 4,230

OTHER INTANGIBLE ASSETS AND M99

OTHER INTANGIBLE ASSETS AND MORTGAGE SERVICING RIGHTS (Mortgage Servicing Rights) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Servicing Asset at Amortized Value, Balance [Roll Forward]
Additions through acquisition		$ 2,172		$ 0		$ 0
Serviced Loans
Servicing Assets at Amortized Value [Line Items]
Loans serviced for others		1,855,000		1,278,000
Mortgage Servicing Rights
Servicing Assets at Amortized Value [Line Items]
Custodial accounts		8,700		6,500
Servicing Asset at Amortized Value, Balance [Roll Forward]
Balance, beginning of the year		9,030	[1]	8,086	[1]	6,244
Amounts capitalized		5,313		3,023		2,913
Amortization		(3,220)		(2,079)		(2,371)
Valuation adjustments in the period		0		0		1,300
Balance, end of the year	[1]	13,295		$ 9,030		8,086
Valuation Allowance		$ 0				$ 0
[1]	no valuation allowance

FAIR VALUE OF FINANCIAL INST100

FAIR VALUE OF FINANCIAL INSTRUMENTS (Assets and Liabilities Measured at Fair Value) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Fair Value	$ 34,134	$ 40,258
Securities—available-for-sale	1,138,573	411,021
Held-to-maturity Securities, Fair Value	226,627	137,608
Advances from FHLB at fair value	133,381	32,250
Reported Value Measurement [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	261,917	126,072
Bank-owned life insurance	156,865	63,759
Reported Value Measurement [Member] | Level 2 and Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Fair Value	34,134	40,258
Reported Value Measurement [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	1,138,573	411,021
Loans receivable held for sale	44,712	2,786
Deposits, Demand NOW and Money Market Accounts, Fair Value Disclosure	5,416,556	2,227,292
Deposits, Savings, Fair Value Disclosure	1,284,642	901,142
Deposits, Certificates of Deposit, Fair Value Disclosure	1,353,870	770,516
Advances from FHLB at fair value	133,381	32,250
Other borrowings	98,325	77,185
Reported Value Measurement [Member] | Level 2 [Member] | Interest Rate Lock Commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	11,984	6,290
Reported Value Measurement [Member] | Level 2 [Member] | Interest Rate Forward Sales Commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	11,984	6,290
Reported Value Measurement [Member] | Level 2 [Member] | Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	471	317
Derivative liabilities	50	198
Reported Value Measurement [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	220,666	131,258
Loans receivable	7,314,504	3,831,034
FHLB stock	16,057	27,036
MSRs	13,295	9,030
Junior subordinated debentures net of unamortized deferred issuance costs at fair value	92,480	78,001
Estimate of Fair Value Measurement [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	261,917	126,072
Bank-owned life insurance	156,865	63,759
Estimate of Fair Value Measurement [Member] | Level 2 and Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Fair Value	34,134	40,258
Estimate of Fair Value Measurement [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	1,138,573	411,021
Loans receivable held for sale	45,600	2,807
Deposits, Demand NOW and Money Market Accounts, Fair Value Disclosure	5,416,556	2,227,292
Deposits, Savings, Fair Value Disclosure	1,284,642	901,142
Deposits, Certificates of Deposit, Fair Value Disclosure	1,332,825	770,516
Advances from FHLB at fair value	133,381	32,250
Other borrowings	98,325	77,185
Estimate of Fair Value Measurement [Member] | Level 2 [Member] | Interest Rate Lock Commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	11,984	6,290
Estimate of Fair Value Measurement [Member] | Level 2 [Member] | Interest Rate Forward Sales Commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	11,984	6,290
Estimate of Fair Value Measurement [Member] | Level 2 [Member] | Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	471	317
Derivative liabilities	50	198
Estimate of Fair Value Measurement [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Held-to-maturity Securities, Fair Value	226,627	137,608
Loans receivable	7,084,631	3,722,179
FHLB stock	16,057	27,036
MSRs	17,370	12,987
Junior subordinated debentures net of unamortized deferred issuance costs at fair value	$ 92,480	$ 78,001

FAIR VALUE OF FINANCIAL INST101

FAIR VALUE OF FINANCIAL INSTRUMENTS (Fair Value By Balance Sheet Location) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Assets:
Trading Securities, Fair Value	$ 34,134	$ 40,258
Securities—available-for-sale	1,138,573	411,021
Liabilities:
Advances from FHLB at fair value	133,381	32,250
Fair Value, Measurements, Recurring [Member]
Assets:
Trading Securities, Fair Value	34,134	40,258
Securities—available-for-sale	1,138,573	411,021
Assets, Fair Value Disclosure	1,185,162	457,886
Liabilities:
Advances from FHLB at fair value	133,381	32,250
Junior subordinated debentures at fair value	92,480	78,001
Financial and Nonfinancial Liabilities, Fair Value Disclosure	237,895	116,739
Fair Value, Measurements, Recurring [Member] | Interest Rate Contract [Member]
Assets:
Derivatives	11,984	317
Liabilities:
Derivatives	11,984	198
Fair Value, Measurements, Recurring [Member] | Interest Rate Swap [Member]
Assets:
Derivatives	471	6,290
Liabilities:
Derivatives	50	6,290
Fair Value, Measurements, Recurring [Member] | U.S. Government and agency obligations
Assets:
Trading Securities, Fair Value	1,368	1,505
Securities—available-for-sale	30,231	29,770
Fair Value, Measurements, Recurring [Member] | Municipal bonds
Assets:
Trading Securities, Fair Value	341	1,440
Securities—available-for-sale	143,319	50,028
Fair Value, Measurements, Recurring [Member] | Corporate bonds
Assets:
Securities—available-for-sale	15,981	5,018
Fair Value, Measurements, Recurring [Member] | TPS and TRUP CDOs [Member]
Assets:
Trading Securities, Fair Value	18,699	19,118
Fair Value, Measurements, Recurring [Member] | Mortgage Backed Securities, Other [Member]
Assets:
Trading Securities, Fair Value	13,663	18,136
Securities—available-for-sale	918,259	300,810
Fair Value, Measurements, Recurring [Member] | Equity securities
Assets:
Trading Securities, Fair Value	63	59
Securities—available-for-sale	98
Fair Value, Measurements, Recurring [Member] | Asset-backed securities
Assets:
Securities—available-for-sale	30,685	25,395
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Assets:
Trading Securities, Fair Value	0	0
Securities—available-for-sale	0	0
Assets, Fair Value Disclosure	0	0
Liabilities:
Advances from FHLB at fair value	0	0
Junior subordinated debentures at fair value	0	0
Financial and Nonfinancial Liabilities, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Interest Rate Contract [Member]
Assets:
Derivatives	0	0
Liabilities:
Derivatives	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Interest Rate Swap [Member]
Assets:
Derivatives	0	0
Liabilities:
Derivatives	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | U.S. Government and agency obligations
Assets:
Trading Securities, Fair Value	0	0
Securities—available-for-sale	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Municipal bonds
Assets:
Trading Securities, Fair Value	0	0
Securities—available-for-sale	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Corporate bonds
Assets:
Securities—available-for-sale	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | TPS and TRUP CDOs [Member]
Assets:
Trading Securities, Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Mortgage Backed Securities, Other [Member]
Assets:
Trading Securities, Fair Value	0	0
Securities—available-for-sale	0	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Equity securities
Assets:
Trading Securities, Fair Value	0	0
Securities—available-for-sale	0
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Asset-backed securities
Assets:
Securities—available-for-sale	0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Assets:
Trading Securities, Fair Value	15,435	21,140
Securities—available-for-sale	1,138,573	411,021
Assets, Fair Value Disclosure	1,166,463	438,451
Liabilities:
Advances from FHLB at fair value	133,381	32,250
Junior subordinated debentures at fair value	0	0
Financial and Nonfinancial Liabilities, Fair Value Disclosure	145,415	38,738
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Interest Rate Contract [Member]
Assets:
Derivatives	11,984	0
Liabilities:
Derivatives	11,984	198
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Interest Rate Swap [Member]
Assets:
Derivatives	471	6,290
Liabilities:
Derivatives	50	6,290
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | U.S. Government and agency obligations
Assets:
Trading Securities, Fair Value	1,368	1,505
Securities—available-for-sale	30,231	29,770
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Municipal bonds
Assets:
Trading Securities, Fair Value	341	1,440
Securities—available-for-sale	143,319	50,028
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Corporate bonds
Assets:
Securities—available-for-sale	15,981	5,018
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | TPS and TRUP CDOs [Member]
Assets:
Trading Securities, Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Mortgage Backed Securities, Other [Member]
Assets:
Trading Securities, Fair Value	13,663	18,136
Securities—available-for-sale	918,259	300,810
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Equity securities
Assets:
Trading Securities, Fair Value	63	59
Securities—available-for-sale	98
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Asset-backed securities
Assets:
Securities—available-for-sale	30,685	25,395
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Assets:
Trading Securities, Fair Value	18,699	19,118
Securities—available-for-sale	0	0
Assets, Fair Value Disclosure	18,699	19,435
Liabilities:
Advances from FHLB at fair value	0	0
Junior subordinated debentures at fair value	92,480	78,001
Financial and Nonfinancial Liabilities, Fair Value Disclosure	92,480	78,001
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Interest Rate Contract [Member]
Assets:
Derivatives	0	317
Liabilities:
Derivatives	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Interest Rate Swap [Member]
Assets:
Derivatives	0	0
Liabilities:
Derivatives	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | U.S. Government and agency obligations
Assets:
Trading Securities, Fair Value	0	0
Securities—available-for-sale	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Municipal bonds
Assets:
Trading Securities, Fair Value	0	0
Securities—available-for-sale	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Corporate bonds
Assets:
Securities—available-for-sale	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | TPS and TRUP CDOs [Member]
Assets:
Trading Securities, Fair Value	18,699	19,118
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Mortgage Backed Securities, Other [Member]
Assets:
Trading Securities, Fair Value	0	0
Securities—available-for-sale	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Equity securities
Assets:
Trading Securities, Fair Value	0	0
Securities—available-for-sale	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Asset-backed securities
Assets:
Securities—available-for-sale	$ 0	$ 0

FAIR VALUE OF FINANCIAL INST102

FAIR VALUE OF FINANCIAL INSTRUMENTS (Asset Inputs) (Details) - Weighted Average [Member] - Level 3 [Member] - Income Approach Valuation Technique [Member]	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
TRUP CDO Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate		3.96%
TPS Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	5.61%	5.26%
Junior Subordinated Debt [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	5.61%	5.26%

FAIR VALUE OF FINANCIAL INST103

FAIR VALUE OF FINANCIAL INSTRUMENTS (Unobservable Inputs Rollforward) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	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	$ 78,001	$ 73,928
Liabilities (gains) losses	(2,714)	4,073
Purchases, issuances and settlements	11,765		$ 0
Paydowns and maturities	0	0
Transfers in and/or out of Level 3	0		0
Ending balance	92,480	78,001	73,928
TPS and TRUP CDOs [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	19,119	35,140
Assets gains (losses)	537	5,481
Purchases, issuances and settlements	5,697		0
Paydowns and maturities	(6,654)	21,502
Transfers in and/or out of Level 3	0		0
Ending balance	$ 18,699	$ 19,119	$ 35,140

FAIR VALUE OF FINANCIAL INST104

FAIR VALUE OF FINANCIAL INSTRUMENTS (Assets Measured on Nonrecurring Basis) (Details) - Nonrecurring [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	$ 2,372	$ 4,725
REO	11,627	3,352
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]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	(341)	(965)
Impaired loans	2,372	4,725
REO	11,627	3,352
Impaired Loans [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	(110)	(512)
Real Estate [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	$ (231)	$ (453)

BANNER CORPORATION (PARENT C105

BANNER CORPORATION (PARENT COMPANY ONLY) (Statements of Financial Position) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Oct. 01, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
ASSETS
Other assets	$ 56,943		$ 29,328
Total assets	9,796,298	$ 9,900,000	4,723,163
LIABILITIES AND SHAREHOLDERS’ EQUITY
Junior subordinated debentures at fair value	92,480		78,001
Shareholders’ equity	1,300,059		582,888	$ 538,331	$ 506,619
Total liabilities and stockholders' equity	9,796,298		4,723,163
Banner Corporation
ASSETS
Cash	58,232		52,124
Investment in trust equities	4,212		3,716
Investment in subsidiaries	1,319,348		610,732
Other assets	21,134		8,279
Total assets	1,402,926		674,851
LIABILITIES AND SHAREHOLDERS’ EQUITY
Miscellaneous liabilities	7,846		2,446
Deferred tax liability	2,541		11,516
Junior subordinated debentures at fair value	92,480		78,001
Shareholders’ equity	1,300,059		582,888
Total liabilities and stockholders' equity	$ 1,402,926		$ 674,851

BANNER CORPORATION (PARENT C106

BANNER CORPORATION (PARENT COMPANY ONLY) (Statements of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	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, 2015	Dec. 31, 2014	Dec. 31, 2013
INTEREST INCOME:
Interest-bearing deposits	$ 92,099	$ 52,188	$ 51,457	$ 46,536	$ 46,661	$ 47,064	$ 43,808	$ 42,339	$ 41,607	$ 41,893	$ 42,248	$ 40,968	$ 242,279	$ 179,872	$ 166,716
OTHER INCOME (EXPENSE):
Other income													2,821	1,885	2,784
Other expenses													(17,565)	(13,619)	(12,474)
Income before provision for income taxes	10,201	19,589	19,864	18,318	17,544	22,105	25,683	15,790	17,707	17,995	17,744	16,957	67,971	81,122	70,403
PROVISION FOR INCOME TAXES	3,308	6,642	6,615	6,184	5,831	7,284	8,696	5,241	6,281	6,459	6,076	5,373	22,749	27,052	24,189
NET INCOME	$ 6,893	$ 12,947	$ 13,249	$ 12,134	$ 11,713	$ 14,821	$ 16,987	$ 10,549	$ 11,426	$ 11,536	$ 11,668	$ 11,584	45,222	54,070	46,214
Banner Corporation
INTEREST INCOME:
Interest-bearing deposits													122	96	82
OTHER INCOME (EXPENSE):
Dividend income from subsidiaries													170,260	26,027	24,725
Equity in undistributed (distributions in excess of) income of subsidiaries													(116,120)	33,612	23,653
Other income													69	67	3,016
Net change in valuation of financial instruments carried at fair value													(2,714)	(4,073)	(865)
Interest on other borrowings													(3,247)	(2,914)	(2,968)
Other expenses													(7,175)	(2,519)	(2,794)
Income before provision for income taxes													41,195	50,296	44,849
PROVISION FOR INCOME TAXES													(4,027)	(3,774)	(1,365)
NET INCOME													$ 45,222	$ 54,070	$ 46,214

BANNER CORPORATION (PARENT C107

BANNER CORPORATION (PARENT COMPANY ONLY) (Statements of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	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, 2015	Dec. 31, 2014	Dec. 31, 2013
OPERATING ACTIVITIES:
Net income	$ 6,893	$ 12,947	$ 13,249	$ 12,134	$ 11,713	$ 14,821	$ 16,987	$ 10,549	$ 11,426	$ 11,536	$ 11,668	$ 11,584	$ 45,222	$ 54,070	$ 46,214
Adjustments to reconcile net income to net cash provided from operating activities:
Increase (decrease) in deferred taxes													(3,906)	2,966	7,869
Net change in valuation of financial instruments carried at fair value													813	(1,374)	2,278
Increase in other assets													(7,319)	(2,310)	19,426
Increase (decrease) in other liabilities													4,090	3,370	4,327
Net cash provided from operating activities													15,369	98,066	95,366
INVESTING ACTIVITIES:
Net cash used by investing activities													15,059	(164,067)	(206,421)
FINANCING ACTIVITIES
Issuance of stock for shareholder reinvestment program													34	127	72
Cash dividends paid													(17,170)	(13,462)	(7,799)
Net cash provided from financing activities													105,417	54,724	67,106
NET CHANGE IN CASH AND CASH EQUIVALENTS													135,845	(11,277)	(43,949)
CASH AND DUE FROM BANKS, BEGINNING OF YEAR				71,077									71,077
CASH AND DUE FROM BANKS, END OF YEAR	117,657				71,077								117,657	71,077
Banner Corporation
OPERATING ACTIVITIES:
Net income													45,222	54,070	46,214
Adjustments to reconcile net income to net cash provided from operating activities:
Distributions in excess of (Equity in undistributed) income of subsidiaries													116,120	(33,612)	(23,653)
Increase (decrease) in deferred taxes													(1,398)	(1,444)	17
Net change in valuation of financial instruments carried at fair value													2,714	4,073	865
Increase in other assets													(10,655)	(3,822)	(4,655)
Increase (decrease) in other liabilities													3,919	222	(1,921)
Net cash provided from operating activities													155,922	19,487	16,867
INVESTING ACTIVITIES:
Funds transferred to deferred compensation trust													(26)	(26)	(27)
Acquisitions													132,652	0	0
Net cash used by investing activities													(132,678)	(26)	(27)
FINANCING ACTIVITIES
Issuance of stock for shareholder reinvestment program													34	127	72
Cash dividends paid													(17,170)	(13,462)	(7,798)
Net cash provided from financing activities													(17,136)	(13,335)	(7,726)
NET CHANGE IN CASH AND CASH EQUIVALENTS													6,108	6,126	9,114
CASH AND DUE FROM BANKS, BEGINNING OF YEAR				$ 52,124				$ 45,998				$ 36,884	52,124	45,998	36,884
CASH AND DUE FROM BANKS, END OF YEAR	$ 58,232				$ 52,124				$ 45,998				$ 58,232	$ 52,124	$ 45,998

STOCK REPURCHASES (Details)

STOCK REPURCHASES (Details) - Common Stock [Member] - Banner Corporation Share Repurchase Plan [Member] - shares	12 Months Ended
	Dec. 31, 2014	Mar. 26, 2014
Stock repurchases
Stock Repurchase Program, Number of Shares Authorized to be Repurchased		978,826
Stock Repurchase Program, Number of Shares Authorized to be Repurchased, Percent of Total Outstanding		5.00%
Stock Repurchased During Period, Shares	0

CALCULATION OF EARNINGS PER 109

CALCULATION OF EARNINGS PER COMMON SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	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, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share [Abstract]
NET INCOME AVAILABLE TO COMMON SHAREHOLDERS													$ 45,222	$ 54,070	$ 46,214
Weighted average number of common shares outstanding
Basic weighted average shares outstanding (in shares)													23,801,373	19,359,409	19,361,411
Diluted weighted shares outstanding (in shares)													23,866,621	19,402,656	19,397,360
Earnings per common share
Basic (in dollars per share)	$ 0.20	$ 0.62	$ 0.64	$ 0.61	$ 0.60	$ 0.76	$ 0.88	$ 0.55	$ 0.59	$ 0.60	$ 0.60	$ 0.60	$ 1.90	$ 2.79	$ 2.39
Diluted (in dollars per share)	$ 0.20	$ 0.62	$ 0.64	$ 0.61	$ 0.60	$ 0.76	$ 0.88	$ 0.54	$ 0.59	$ 0.59	$ 0.60	$ 0.60	$ 1.89	$ 2.79	$ 2.38

CALCULATION OF EARNINGS PER 110

CALCULATION OF EARNINGS PER COMMON SHARE (Textuals) (Details)	12 Months Ended
	Dec. 31, 2015shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Unvested restricted stock shares included in computation of diluted earnings per share	231,562
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	5,000
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 FINANCIAL111

SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	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, 2015	Dec. 31, 2014	Dec. 31, 2013
Selected Quarterly Financial Information [Abstract]
Interest income	$ 96,495	$ 54,793	$ 54,076	$ 49,069	$ 49,251	$ 49,764	$ 46,540	$ 45,106	$ 44,596	$ 45,037	$ 45,571	$ 44,508	$ 254,433	$ 190,661	$ 179,712
Interest expense	4,396	2,605	2,619	2,533	2,590	2,700	2,732	2,767	2,989	3,144	3,323	3,540	12,154	10,789	12,996
Net interest income before provision for loan losses	92,099	52,188	51,457	46,536	46,661	47,064	43,808	42,339	41,607	41,893	42,248	40,968	242,279	179,872	166,716
Provision for loan losses	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Net interest income	92,099	52,188	51,457	46,536	46,661	47,064	43,808	42,339	41,607	41,893	42,248	40,968	242,279	179,872	166,716
Non-interest income	18,356	14,098	16,141	13,696	12,113	13,536	20,310	9,032	13,029	10,592	10,953	10,088	62,292	54,991	44,662
Other operating expenses	100,254	46,697	47,734	41,914	41,230	38,495	38,435	35,581	36,929	34,490	35,457	34,099	236,600	153,741	140,975
Income before provision for income taxes	10,201	19,589	19,864	18,318	17,544	22,105	25,683	15,790	17,707	17,995	17,744	16,957	67,971	81,122	70,403
PROVISION FOR INCOME TAXES	3,308	6,642	6,615	6,184	5,831	7,284	8,696	5,241	6,281	6,459	6,076	5,373	22,749	27,052	24,189
NET INCOME	$ 6,893	$ 12,947	$ 13,249	$ 12,134	$ 11,713	$ 14,821	$ 16,987	$ 10,549	$ 11,426	$ 11,536	$ 11,668	$ 11,584	$ 45,222	$ 54,070	$ 46,214
Basic earnings (loss) per share (in dollars per share)	$ 0.20	$ 0.62	$ 0.64	$ 0.61	$ 0.60	$ 0.76	$ 0.88	$ 0.55	$ 0.59	$ 0.60	$ 0.60	$ 0.60	$ 1.90	$ 2.79	$ 2.39
Diluted earnings (loss) per share (in dollars per share)	0.20	0.62	0.64	0.61	0.60	0.76	0.88	0.54	0.59	0.59	0.60	0.60	1.89	2.79	2.38
Cumulative dividends declared per common share (in dollars per share)	$ 0.18	$ 0.18	$ 0.18	$ 0.18	$ 0.18	$ 0.18	$ 0.18	$ 0.18	$ 0.15	$ 0.15	$ 0.12	$ 0.12	$ 0.72	$ 0.72	$ 0.54

COMMITMENTS AND CONTINGENCIE112

COMMITMENTS AND CONTINGENCIES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Reserve for Unfunded Loan Commitments	$ 3,900	$ 732
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	$ 2,132,996	1,166,165
Standby letters of credit and financial guarantees
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract or Notional Amount	22,315	9,934
Commitments to originate loans
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract or Notional Amount	32,908	20,988
Commitments to originate loans held for sale
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract or Notional Amount	76,146	29,851
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	37,545	8,714
Loss on Contract Termination for Default	0
Commitments to sell securities related to mortgage banking activities
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract or Notional Amount	$ 41,500	$ 25,000

DERIVATIVES AND HEDGING DERI113

DERIVATIVES AND HEDGING DERIVATIVES AND HEDGING (Derivatives Designated as Hedging, by Balance Sheet Location) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 11,984	$ 6,290
Derivative Liability, Fair Value, Gross Liability	11,984	6,290
Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	11,984	6,290
Derivative Liability, Fair Value, Gross Liability	11,984	6,290
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	6,734	7,089
Derivative Liability, Notional Amount	6,734	7,089
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Loans Receivable [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	938	1,165
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	$ 938	$ 1,165

DERIVATIVES AND HEDGING DERI114

DERIVATIVES AND HEDGING DERIVATIVES AND HEDGING (Derivatives Not Designated as Hedging, by Balance Sheet Location) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 11,984	$ 6,290
Derivative Liability, Fair Value, Gross Liability	11,984	6,290
Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	11,984	6,290
Derivative Liability, Fair Value, Gross Liability	11,984	6,290
Interest Rate Swap [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount		282,000
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	411,583	163,823
Derivative Liability, Notional Amount	334,372	167,686
Not Designated as Hedging Instrument [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	11,517	5,442
Not Designated as Hedging Instrument [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	11,132	5,323
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	293,937	134,512
Derivative Liability, Notional Amount	293,937	134,512
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Loans Receivable [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	327	558
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	11,046	5,125
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	11,046	5,125
Not Designated as Hedging Instrument [Member] | Risk Participation Agreement [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	0	0
Derivative Liability, Notional Amount	7,672	0
Not Designated as Hedging Instrument [Member] | Risk Participation Agreement [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	0
Not Designated as Hedging Instrument [Member] | Risk Participation Agreement [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	36	0
Not Designated as Hedging Instrument [Member] | Mortgage Loan Commitments [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	76,146	29,311
Derivative Liability, Notional Amount	0	0
Not Designated as Hedging Instrument [Member] | Mortgage Loan Commitments [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	428	317
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	0
Not Designated as Hedging Instrument [Member] | Forward Sales Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount	41,500	0
Derivative Liability, Notional Amount	32,763	33,174
Not Designated as Hedging Instrument [Member] | Forward Sales Contracts [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	43	0
Not Designated as Hedging Instrument [Member] | Forward Sales Contracts [Member] | Other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	$ 50	$ 198

DERIVATIVES AND HEDGING DERI115

DERIVATIVES AND HEDGING DERIVATIVES AND HEDGING (Gain (Loss) On Derivatives Not Designated in Hedging Relationship) (Details) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 241	$ 33
Mortgage Loan Commitments [Member] | Mortgage Banking Operations [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	100	221
Forward Sales Contracts [Member] | Mortgage Banking Operations [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 141	$ (188)

DERIVATIVES AND HEDGING DERI116

DERIVATIVES AND HEDGING DERIVATIVES AND HEDGING (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative, Net Liability Position, Aggregate Fair Value	$ 12	$ 6.3
Collateral Already Posted, Aggregate Fair Value	$ 20.8	$ 11.1

DERIVATIVES AND HEDGING DERI117

DERIVATIVES AND HEDGING DERIVATIVES AND HEDGING (Derivative Offsetting) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Offsetting Assets and Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 11,984	$ 6,290
Derivative Asset, Fair Value, Gross Liability	0	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	11,984	6,290
Derivative, Collateral, Obligation to Return Securities	0	(6)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	11,984	6,284
Derivative Liability, Fair Value, Gross Liability	11,984	6,290
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	11,984	6,290
Derivative, Collateral, Right to Reclaim Securities	0	(6)
Derivative, Collateral, Right to Reclaim Cash	(11,984)	(6,279)
Derivative Liability, Fair Value, Amount Offset Against Collateral	0	5
Interest Rate Swap [Member]
Offsetting Assets and Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset	11,984	6,290
Derivative Asset, Fair Value, Gross Liability	0	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	11,984	6,290
Derivative, Collateral, Obligation to Return Securities	0	(6)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	11,984	6,284
Derivative Liability, Fair Value, Gross Liability	11,984	6,290
Derivative Liability, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	11,984	6,290
Derivative, Collateral, Right to Reclaim Securities	0	(6)
Derivative, Collateral, Right to Reclaim Cash	(11,984)	(6,279)
Derivative Liability, Fair Value, Amount Offset Against Collateral	$ 0	$ 5