Luther Burbank (LBC) 10-Q 10 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	May 03, 2019
Document and Entity Information [Abstract]
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Amendment Flag	false
Entity Registrant Name	Luther Burbank Corp.
Entity Central Index Key	0001475348
Entity Current Reporting Status	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Common Stock Shares Outstanding (in shares)		56,317,625
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1

CONSOLIDATED STATEMENTS OF FINA

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
ASSETS
Cash and cash equivalents	$ 104,575	$ 91,697
Available for sale debt securities, at fair value	638,795	608,528
Held to maturity debt securities, at amortized cost (fair value of $11,376 and $11,625 at March 31, 2019 and December 31, 2018, respectively)	11,450	11,860
Equity securities, at fair value	11,582	11,438
Loans receivable, net of allowance for loan losses of $34,692 and $34,314 as of March 31, 2019 and December 31, 2018, respectively	6,109,576	6,096,316
Accrued interest receivable	21,292	20,220
Federal Home Loan Bank (FHLB) stock, at cost	32,047	31,823
Premises and equipment, net	20,473	20,981
Goodwill	3,297	3,297
Prepaid expenses and other assets	38,929	41,052
Total assets	6,992,016	6,937,212
Liabilities:
Deposits	5,081,831	5,001,040
FHLB advances	1,109,625	1,143,132
Junior subordinated deferrable interest debentures	61,857	61,857
Senior debt $95,000 face amount, 6.5% interest rate, due September 30, 2024 (less debt issuance costs of $676 and $707 at March 31, 2019 and December 31, 2018, respectively)	94,324	94,293
Accrued interest payable	5,476	4,307
Other liabilities and accrued expenses	50,605	51,438
Total liabilities	6,403,718	6,356,067
Commitments and contingencies (Note 14)
Stockholders' equity:
Preferred stock, no par value; 5,000,000 shares authorized; none issued and outstanding at March 31, 2019 and December 31, 2018	0	0
Common stock, no par value; 100,000,000 shares authorized; 56,351,781 and 56,379,066 shares issued and outstanding at March 31, 2019 and December 31, 2018, respectively	452,931	456,378
Retained earnings	138,123	129,806
Accumulated other comprehensive loss, net of taxes	(2,756)	(5,039)
Total stockholders' equity	588,298	581,145
Total liabilities and stockholders' equity	$ 6,992,016	$ 6,937,212

CONSOLIDATED STATEMENTS OF FI_2

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Parenthetical) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Fair value of held-to-maturity securities	$ 11,376,000	$ 11,625,000
Allowance for loan losses	$ 34,692,000	$ 34,314,000
Debt Instrument [Line Items]
Debt interest rate	6.50%
Preferred stock shares authorized (in shares)	5,000,000	5,000,000
Preferred stock shares issued (in shares)	0	0
Preferred stock shares outstanding (in shares)	0	0
Common stock shares authorized (in shares)	100,000,000	100,000,000
Common stock shares issued (in shares)	56,351,781	56,379,066
Common stock shares outstanding (in shares)	56,351,781	56,379,066
Senior Unsecured Term Notes, September 2014 | Senior Unsecured Term Notes
Debt Instrument [Line Items]
Principal	$ 95,000,000	$ 95,000,000
Debt interest rate	6.50%
Unamortized debt issuance costs	$ 676,000	$ 707,000

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Interest and fee income:
Loans	$ 61,053	$ 46,563
Investment securities	3,925	2,472
Cash and cash equivalents	400	246
Total interest and fee income	65,378	49,281
Interest expense:
Deposits	24,288	11,932
FHLB advances	6,772	4,820
Junior subordinated deferrable interest debentures	651	487
Senior debt	1,575	1,577
Total interest expense	33,286	18,816
Net interest income before provision for loan losses	32,092	30,465
Provision for loan losses	300	1,500
Net interest income after provision for loan losses	31,792	28,965
Noninterest income:
Gain on sale of loans	333	0
FHLB dividends	495	594
Other income	552	431
Total noninterest income	1,380	1,025
Noninterest expense:
Compensation and related benefits	10,052	9,619
Deposit insurance premium	498	432
Professional and regulatory fees	441	398
Occupancy	1,390	1,296
Depreciation and amortization	665	714
Data processing	919	788
Marketing	1,154	213
Other expenses	1,130	1,253
Total noninterest expense	16,249	14,713
Income before provision for income taxes	16,923	15,277
Provision for income taxes	4,913	4,175
Net income	$ 12,010	$ 11,102
Basic earnings per common share (in usd per share)	$ 0.21	$ 0.20
Diluted earnings per common share (in usd per share)	0.21	0.20
Dividends per common share (in usd per share)	$ 0.06	$ 0.11

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 12,010	$ 11,102
Unrealized gain (loss) on available for sale debt securities:
Unrealized holding gain (loss) arising during the period	2,504	(2,971)
Tax effect	(724)	843
Net of tax	1,780	(2,128)
Unrealized gain on cash flow hedge:
Unrealized holding gain arising during the period	147	181
Tax effect	(43)	(52)
Net of tax	104	129
Total other comprehensive income (loss)	1,884	(1,999)
Comprehensive income	$ 13,894	$ 9,103

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands	Total	Common Stock	Common StockRestricted Stock Awards	Common StockRestricted Stock Units	Retained Earnings	Accumulated Other Comprehensive (Loss) Income (Net of Taxes) Available for Sale Securities	Accumulated Other Comprehensive (Loss) Income (Net of Taxes) Cash Flow Hedge
Beginning balance (shares) at Dec. 31, 2017		56,422,662
Beginning balance at Dec. 31, 2017	$ 549,745	$ 454,287			$ 102,459	$ (6,214)	$ (787)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	11,102				11,102
Other comprehensive (loss) income	(1,999)					(2,128)	129
Reclassification of prior year tax benefit related to re-measuring deferred taxes on items recorded to other comprehensive income	0				(1,750)	1,529	221
Issuance of restricted stock awards (in shares)		131,140
Vested restricted stock units (in shares)		12,710
Shares withheld to pay taxes on stock based compensation (in shares)			(4,057)
Shares withheld to pay taxes on stock based compensation	(49)	$ (49)
Restricted stock forfeitures (in shares)				(1,400)
Restricted stock forfeitures	(1)	(1)			0
Stock based compensation expense	1,014	$ 1,014
Cash dividends	(6,061)				(6,061)
Ending balance (shares) at Mar. 31, 2018		56,561,055
Ending balance at Mar. 31, 2018	553,751	$ 455,251			105,750	(6,813)	(437)
Beginning balance (shares) at Dec. 31, 2018		56,379,066
Beginning balance at Dec. 31, 2018	581,145	$ 456,378			129,806	(4,935)	(104)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	12,010				12,010
Other comprehensive (loss) income	1,884					1,780	104
Issuance of restricted stock awards (in shares)		297,663
Vested restricted stock units (in shares)		112,302
Shares withheld to pay taxes on stock based compensation (in shares)		(41,522)
Shares withheld to pay taxes on stock based compensation	(404)	$ (404)
Restricted stock forfeitures (in shares)		(2,728)
Restricted stock forfeitures	(1)	$ (2)			1
Stock based compensation expense	840	$ 840
Shares repurchased (in shares)		(393,000)
Shares repurchased	(3,881)	$ (3,881)
Cash dividends	(3,295)				(3,295)
Ending balance (shares) at Mar. 31, 2019		56,351,781
Ending balance at Mar. 31, 2019	$ 588,298	$ 452,931			$ 138,123	$ (2,756)	$ 0

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (UNAUDITED) (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Stockholders' Equity [Abstract]
Cash dividends (in usd per share)	$ 0.06	$ 0.11

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net income	$ 12,010	$ 11,102
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	665	714
Provision for loan losses	300	1,500
Amortization of deferred loan costs, net	2,646	2,334
Amortization of premiums on investment securities, net	362	563
Gain on sale of loans	(333)	0
Stock based compensation expense, net of forfeitures	838	1,013
Change in fair value of mortgage servicing rights	146	131
Change in fair value of equity securities	(144)	0
Other items, net	0	(37)
Effect of changes in:
Accrued interest receivable	(1,072)	(1,236)
Accrued interest payable	1,169	548
Prepaid expenses and other assets	1,543	(156)
Other liabilities and accrued expenses	(868)	(6,761)
Net cash provided by operating activities	17,262	9,715
Cash flows from investing activities:
Proceeds from maturities and paydowns of available for sale debt securities	16,263	20,965
Proceeds from maturities and paydowns of held to maturity debt securities	399	55
Purchases of available for sale debt securities	(44,377)	(59,647)
Purchases of held to maturity debt securities	0	(5,375)
Net increase in loans receivable	(69,765)	(287,028)
Proceeds from loans held for sale previously classified as portfolio loans	53,772	0
Purchase of FHLB stock, net	(224)	(5,290)
Purchase of premises and equipment	(157)	(123)
Net cash used in investing activities	(44,089)	(336,443)
Cash flows from financing activities:
Net increase in customer deposits	80,791	162,788
Proceeds from long-term FHLB advances	75,000	100,000
Repayment of long-term FHLB advances	(7)	(7)
Net change in short-term FHLB advances	(108,500)	68,900
Shares withheld for taxes on vested restricted stock	(404)	(49)
Shares repurchased	(3,881)	0
Cash paid for dividends	(3,294)	(6,061)
Net cash provided by financing activities	39,705	325,571
Increase (decrease) in cash and cash equivalents	12,878	(1,157)
Cash and cash equivalents, beginning of period	91,697	75,578
Cash and cash equivalents, end of period	104,575	74,421
Supplemental disclosure of cash flow information: Cash paid during the period for:
Interest	32,117	18,268
Income taxes	10	158
Non-cash investing activity:
Loans transferred to held for sale	$ 53,559	$ 0

NATURE OF OPERATIONS

NATURE OF OPERATIONS	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
NATURE OF OPERATIONS	NATURE OF OPERATIONS Organization Luther Burbank Corporation (the ‘‘Company’’), a California corporation headquartered in Santa Rosa, is the bank holding company for its wholly-owned subsidiary, Luther Burbank Savings (the "Bank"), and its wholly-owned subsidiary, Burbank Investor Services. The Company also owns Burbank Financial Inc., a real estate investment company, and all the common interests in Luther Burbank Statutory Trusts I and II, entities created to issue trust preferred securities. The Bank conducts its business from its headquarters in Manhattan Beach, California. It has nine full service branches in California located in Sonoma, Marin, Santa Clara, and Los Angeles Counties and one full service branch in Washington located in King County. Additionally, there are seven loan production offices located throughout California, as well as a loan production office in Clackamas County, Oregon. Basis of Presentation The accompanying unaudited consolidated financial statements have been prepared in accordance with the instructions to Form 10-Q and, therefore, do not include all footnotes as would be necessary for a fair presentation of financial position, results of operations and comprehensive income, changes in stockholders’ equity and cash flows in conformity with accounting principles generally accepted in the United States of America (“GAAP”). However, these interim unaudited consolidated financial statements reflect all adjustments (consisting solely of normal recurring adjustments and accruals) which, in the opinion of management, are necessary for a fair presentation of financial position, results of operations and comprehensive income, changes in stockholders’ equity and cash flows for the interim periods presented. These unaudited consolidated financial statements have been prepared on a basis consistent with, and should be read in conjunction with, the audited consolidated financial statements as of and for the year ended December 31, 2018 , and the notes thereto, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018 filed with the SEC, under the Securities and Exchange Act of 1934, (the “Exchange Act”). The unaudited consolidated financial statements include the accounts of the Company and its subsidiaries. All intercompany accounts and transactions have been eliminated. The results of operations for the three months ended March 31, 2019 are not necessarily indicative of the results of operations that may be expected for any other interim period or for the year ending December 31, 2019 . The Company’s accounting and reporting policies conform to GAAP and to general practices within the banking industry. Use of Estimates Management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the unaudited consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. These estimates and assumptions affect the amounts reported in the unaudited consolidated financial statements and the disclosures provided, and actual results could differ. Earnings Per Share ("EPS") Basic earnings per common share represents the amount of earnings for the period available to each share of common stock outstanding during the reporting period. Basic EPS is computed based upon net income divided by the weighted average number of common shares outstanding during the year. In determining the weighted average number of shares outstanding, vested restricted stock units are included. Diluted EPS represents the amount of earnings for the period available to each share of common stock outstanding including common stock that would have been outstanding assuming the issuance of common shares for all dilutive potential common shares outstanding during each reporting period. Diluted EPS is computed based upon net income divided by the weighted average number of common shares outstanding during each period, adjusted for the effect of dilutive potential common shares, such as restricted stock awards and units, calculated using the treasury stock method. (Dollars in thousands, except per share amounts) Three Months Ended March 31, 2019 2018 Net income $ 12,010 $ 11,102 Weighted average basic common shares outstanding 56,519,809 56,190,970 Add: Dilutive effects of assumed vesting of restricted stock 202,887 564,184 Weighted average diluted common shares outstanding 56,722,696 56,755,154 Income per common share: Basic EPS $ 0.21 $ 0.20 Diluted EPS $ 0.21 $ 0.20 Anti-dilutive shares not included in calculation of diluted earnings per share 13,981 — New Financial Accounting Standards FASB ASU 2016-01 In January 2016, the FASB issued ASU 2016-01 which provided guidance to enhance the reporting model for financial instruments to provide users of financial statements with more decision-useful information. This update contains several provisions, including but not limited to (1) requiring equity investments, with certain exceptions, to be measured at fair value with changes in fair value recognized in net income; (2) simplifying the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; (3) eliminating the requirement to disclose the method(s) and significant assumptions used to estimate fair value; and (4) requiring separate presentation of financial assets and liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements. The update also changes certain financial statement disclosure requirements, including requiring disclosures of the fair value of financial instruments be made on the basis of exit price. The update was effective for public business entities ("PBEs") for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. As an emerging growth company, the Company was permitted to adopt this guidance on January 1, 2019 and, as a result, reclassified $399 thousand of unrealized losses on equity securities from other comprehensive income to retained earnings. Subsequent changes in the unrealized gain or loss on equity securities will be recorded through other noninterest income. Additionally, $11.4 million of equity securities were reclassified from available for sale securities to equity securities.

INVESTMENT SECURITIES

INVESTMENT SECURITIES	3 Months Ended
	Mar. 31, 2019
Investments, Debt and Equity Securities [Abstract]
INVESTMENT SECURITIES	INVESTMENT SECURITIES Available for Sale The following tables summarize the amortized cost and the estimated fair value of available for sale debt securities as of the dates indicated: (Dollars in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value At March 31, 2019: Government and Government Sponsored Entities: Residential mortgage backed securities and collateralized mortgage obligations ("MBS and CMOs") $ 181,485 $ 197 $ (1,878 ) $ 179,804 Commercial MBS and CMOs 325,078 1,693 (1,997 ) 324,774 Agency bonds 135,102 26 (1,897 ) 133,231 U.S. Treasury 1,008 — (22 ) 986 Total available for sale debt securities $ 642,673 $ 1,916 $ (5,794 ) $ 638,795 At December 31, 2018: Government and Government Sponsored Entities: Residential MBS and CMOs $ 194,297 $ 339 $ (2,523 ) $ 192,113 Commercial MBS and CMOs 294,276 979 (2,304 ) 292,951 Agency bonds 125,329 7 (2,848 ) 122,488 U.S. Treasury 1,008 — (32 ) 976 Total available for sale debt securities $ 614,910 $ 1,325 $ (7,707 ) $ 608,528 Net unrealized losses on available for sale investment securities are recorded as accumulated other comprehensive income within stockholders’ equity and totaled $2.8 million and $4.9 million , net of $1.1 million and $2.0 million in tax assets at March 31, 2019 and December 31, 2018 , respectively. With the exception of the adoption of ASU 2016-01 as discussed in Note 1 to the unaudited consolidated financial statements, there were no sales or transfers of available for sale investment securities and no realized gains or losses on these securities during the three months ended March 31, 2019 and 2018 . The following tables summarize the gross unrealized losses and fair value of available for sale debt securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position: March 31, 2019 Less than 12 Months 12 Months or More Total (Dollars in thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Government and Government Sponsored Entities: Residential MBS and CMOs $ 43,757 $ (162 ) $ 108,121 $ (1,716 ) $ 151,878 $ (1,878 ) Commercial MBS and CMOs 35,400 (392 ) 149,246 (1,605 ) 184,646 (1,997 ) Agency bonds 14,607 (90 ) 115,598 (1,807 ) 130,205 (1,897 ) U.S. Treasury — — 986 (22 ) 986 (22 ) Total available for sale debt securities $ 93,764 $ (644 ) $ 373,951 $ (5,150 ) $ 467,715 $ (5,794 ) At March 31, 2019 , the Company held 80 residential MBS and CMOs of which 56 were in a loss position and 39 had been in a loss position for twelve months or more. The Company held 38 commercial MBS and CMOs of which 24 were in a loss position and 18 had been in a loss position for twelve months or more. The Company held 15 agency bonds of which 14 were in a loss position and had been for twelve months or more. The Company held 1 U.S. Treasury note at March 31, 2019 . This note was in a loss position for greater than 12 months. December 31, 2018 Less than 12 Months 12 Months or More Total (Dollars in thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Government and Government Sponsored Entities: Residential MBS and CMOs $ 31,728 $ (304 ) $ 102,503 $ (2,219 ) $ 134,231 $ (2,523 ) Commercial MBS and CMOs 58,725 (432 ) 114,159 (1,872 ) 172,884 (2,304 ) Agency bonds 4,906 (18 ) 114,575 (2,830 ) 119,481 (2,848 ) U.S. Treasury — — 976 (32 ) 976 (32 ) Total available for sale debt securities $ 95,359 $ (754 ) $ 332,213 $ (6,953 ) $ 427,572 $ (7,707 ) At December 31, 2018 , the Company held 82 residential MBS and CMOs of which 45 were in a loss position and 40 had been in a loss position for twelve months or more. The Company held 34 commercial MBS and CMOs of which 23 were in a loss position and 16 had been in a loss position for twelve months or more. The Company held 14 agency bonds of which 13 were in a loss position and 12 had been in a loss position for twelve months or more. The Company held 1 U.S. Treasury note at December 31, 2018 . This note was in a loss position for greater than 12 months. The unrealized losses on the Company’s investments were caused by interest rate changes. In addition, the contractual cash flows of these investments are guaranteed by the U.S. government or agencies sponsored by the U.S. government. Accordingly, it is expected that the securities will not be settled at a price less than amortized cost. Because the decline in market value is attributable to changes in interest rates but not credit quality, and because the Company has the ability and intent to hold those investments until a recovery of fair value, which may be maturity, the Company does not consider these investments to be other-than-temporarily impaired at March 31, 2019 and December 31, 2018 . As of March 31, 2019 and December 31, 2018 , there were no holdings of securities of any one issuer in an amount greater than 10% of stockholders' equity, other than the U.S. government and its agencies. Held to Maturity The following tables summarize the amortized cost and estimated fair value of held to maturity investment securities as of the dates indicated: (Dollars in thousands) Amortized Cost Gross Unrecognized Gains Gross Unrecognized Losses Estimated Fair Value As of March 31, 2019: Government Sponsored Entities: Residential MBS $ 11,187 $ 40 $ (114 ) $ 11,113 Other investments 263 — — 263 Total held to maturity investment securities $ 11,450 $ 40 $ (114 ) $ 11,376 As of December 31, 2018: Government Sponsored Entities: Residential MBS $ 11,593 $ 27 $ (262 ) $ 11,358 Other investments 267 — — 267 Total held to maturity investment securities $ 11,860 $ 27 $ (262 ) $ 11,625 The following tables summarize the gross unrecognized losses and fair value of held to maturity investment securities, aggregated by investment category and length of time that individual securities have been in a continuous unrecognized loss position: Less than 12 Months 12 Months or More Total (Dollars in thousands) Fair Value Unrecognized Losses Fair Value Unrecognized Losses Fair Value Unrecognized Losses As of March 31, 2019: Government Sponsored Entities: Residential MBS $ — $ — $ 8,661 $ (114 ) $ 8,661 $ (114 ) As of December 31, 2018: Government Sponsored Entities: Residential MBS $ 6,481 $ (111 ) $ 3,739 $ (151 ) $ 10,220 $ (262 ) At March 31, 2019 , the Company had 7 held to maturity residential MBS of which 4 were in a loss position and 4 had been in a loss position for twelve months or more. At December 31, 2018 , the Company held 7 held to maturity residential MBS of which 6 were in a loss position and 3 had been in a loss position for twelve months or more. The unrecognized losses on the Company’s held to maturity investments were caused by interest rate changes. In addition, the contractual cash flows of these investments are guaranteed by agencies sponsored by the U.S. government. Accordingly, it is expected that the securities will not be settled at a price less than amortized cost. Because the decline in market value is attributable to changes in interest rates but not credit quality, and because the Company has the ability and intent to hold those investments until maturity, the Company does not consider those investments to be other-than-temporarily impaired at March 31, 2019 and December 31, 2018 . The following table summarizes the scheduled maturities of available for sale and held to maturity investment securities as of March 31, 2019 : March 31, 2019 (Dollars in thousands) Amortized Cost Fair Value Available for sale debt securities One to five years $ 118,413 $ 116,584 Five to ten years 4,685 4,663 Beyond ten years 13,012 12,970 MBS and CMOs 506,563 504,578 Total available for sale debt securities $ 642,673 $ 638,795 Held to maturity investments securities Beyond ten years $ 263 $ 263 MBS 11,187 11,113 Total held to maturity debt securities $ 11,450 $ 11,376 The amortized cost and fair value of debt securities are shown by contractual maturity. Expected maturities may differ from contractual maturities if borrowers have the right to call or prepay obligations with or without call or prepayment penalties. As such, mortgage backed securities and collateralized mortgage obligations are not included in the maturity categories above and instead are shown separately. No securities were pledged as of March 31, 2019 and December 31, 2018 . Equity Securities Equity securities consist of investments in the CRA Qualified Investment Fund. At March 31, 2019 and December 31, 2018 , the fair value of equity securities totaled $11.6 million and $11.4 million , respectively. Prior to January 1, 2019, equity securities were included with available for sale investment securities and stated at fair value with unrealized gains and losses reported in other comprehensive income. As of January 1, 2019, $399 thousand of unrealized losses on equity securities were reclassified from other comprehensive income to retained earnings. Subsequent changes in fair value are recognized in other noninterest income and totaled $144 thousand during the three months ended March 31, 2019 . There were no sales of equity securities during the three months ended March 31, 2019 .

LOANS

LOANS	3 Months Ended
	Mar. 31, 2019
Receivables [Abstract]
LOANS	LOANS Loans consist of the following: (Dollars in thousands) March 31, December 31, Permanent mortgages on: Multifamily residential $ 3,747,716 $ 3,650,967 Single family residential 2,141,989 2,231,802 Commercial real estate 190,082 183,559 Construction and land loans 13,188 12,656 Non-Mortgage (‘‘NM’’) loans 100 100 Total 6,093,075 6,079,084 Deferred loan costs, net 51,193 51,546 Allowance for loan losses (34,692 ) (34,314 ) Loans held for investment, net $ 6,109,576 $ 6,096,316 Certain loans have been pledged to secure borrowing arrangements (see Note 7). The following table summarizes activity in and the allocation of the allowance for loan losses by portfolio segment: (Dollars in thousands) Multifamily Residential Single Family Residential Commercial Real Estate Land, Construction and NM Total Three months ended March 31, 2019 Allowance for loan losses: Beginning balance allocated to portfolio segments $ 21,326 $ 10,125 $ 2,441 $ 422 $ 34,314 Provision for (reversal of) loan losses 720 (239 ) (163 ) (18 ) 300 Charge-offs — — — — — Recoveries — 3 — 75 78 Ending balance allocated to portfolio segments $ 22,046 $ 9,889 $ 2,278 $ 479 $ 34,692 Three months ended March 31, 2018 Allowance for loan losses: Beginning balance allocated to portfolio segments $ 18,588 $ 9,044 $ 1,734 $ 946 $ 30,312 Provision for loan losses 1,245 167 63 25 1,500 Charge-offs — — — — — Recoveries — 3 90 75 168 Ending balance allocated to portfolio segments $ 19,833 $ 9,214 $ 1,887 $ 1,046 $ 31,980 The following tables summarize the allocation of the allowance for loan losses by impairment methodology: (Dollars in thousands) Multifamily Residential Single Family Residential Commercial Real Estate Land, Construction and NM Total As of March 31, 2019: Ending allowance balance allocated to: Loans individually evaluated for impairment $ — $ 25 $ — $ — $ 25 Loans collectively evaluated for impairment 22,046 9,864 2,278 479 34,667 Ending balance $ 22,046 $ 9,889 $ 2,278 $ 479 $ 34,692 Loans: Ending balance: individually evaluated for impairment $ 557 $ 4,461 $ — $ — $ 5,018 Ending balance: collectively evaluated for impairment 3,747,159 2,137,528 190,082 13,288 6,088,057 Ending balance $ 3,747,716 $ 2,141,989 $ 190,082 $ 13,288 $ 6,093,075 As of December 31, 2018: Ending allowance balance allocated to: Loans individually evaluated for impairment $ — $ 25 $ — $ — $ 25 Loans collectively evaluated for impairment 21,326 10,100 2,441 422 34,289 Ending balance $ 21,326 $ 10,125 $ 2,441 $ 422 $ 34,314 Loans: Ending balance: individually evaluated for impairment $ 566 $ 6,008 $ — $ — $ 6,574 Ending balance: collectively evaluated for impairment 3,650,401 2,225,794 183,559 12,756 6,072,510 Ending balance $ 3,650,967 $ 2,231,802 $ 183,559 $ 12,756 $ 6,079,084 The Company assigns a risk rating to all loans and periodically performs detailed reviews of all such loans to identify credit risks and to assess the overall collectability of the portfolio. During these internal reviews, management monitors and analyzes the financial condition of borrowers and guarantors, as well as the financial performance and other characteristics of loan collateral. These credit quality indicators are used to assign a risk rating to each individual loan. The risk ratings can be grouped into six major categories, defined as follows: Pass assets are those which are performing according to contract and have no existing or known weaknesses deserving of management’s close attention. The basic underwriting criteria used to approve the loans are still valid, and all payments have essentially been made as planned. Watch assets are expected to have an event occurring in the next 90 to 120 days that will lead to a change in risk rating with the change being either favorable or unfavorable. These assets require heightened monitoring of the event by management. Special mention assets have potential weaknesses that deserve management’s close attention. If left uncorrected, these potential weaknesses may result in deterioration of the repayment prospects for the asset or in the Company’s credit position at some future date. Special mention assets are not adversely classified and do not expose the Company to sufficient risk to warrant adverse classification. Substandard assets are inadequately protected by the current net worth and/or paying capacity of the obligor or by the collateral pledged. These assets have well-defined weaknesses: the primary source of repayment is gone or severely impaired (i.e., bankruptcy or loss of employment) and/or there has been a deterioration in collateral value. In addition, there is the distinct possibility that the Company will sustain some loss, either directly or indirectly (i.e., the cost of monitoring), if the deficiencies are not corrected. A deterioration in collateral value alone does not mandate that an asset be adversely classified if such factor does not indicate that the primary source of repayment is in jeopardy. Doubtful assets have the weaknesses of those classified substandard with the added characteristic that the weaknesses make collection or liquidation in full highly questionable and improbable based on current facts, conditions and values. Loss assets are considered uncollectible and of such little value that their continuance as assets, without establishment of a specific valuation allowance or charge-off, is not warranted. This classification does not necessarily mean that an asset has absolutely no recovery or salvage value; but rather, it is not practical or desirable to defer writing off a basically worthless asset (or portion thereof) even though partial recovery may be affected in the future. The following tables summarize the loan portfolio allocated by management’s internal risk ratings at March 31, 2019 and December 31, 2018 : (Dollars in thousands) Multifamily Residential Single Family Residential Commercial Real Estate Land, Construction and NM Total As of March 31, 2019: Grade: Pass $ 3,681,125 $ 2,103,901 $ 186,242 $ 10,450 $ 5,981,718 Watch 58,340 20,839 3,840 — 83,019 Special mention 5,962 10,486 — 2,838 19,286 Substandard 2,289 6,763 — — 9,052 Total $ 3,747,716 $ 2,141,989 $ 190,082 $ 13,288 $ 6,093,075 As of December 31, 2018: Grade: Pass $ 3,581,468 $ 2,205,528 $ 180,190 $ 10,232 $ 5,977,418 Watch 64,958 20,288 1,887 — 87,133 Special mention 2,607 369 1,482 2,524 6,982 Substandard 1,934 5,617 — — 7,551 Total $ 3,650,967 $ 2,231,802 $ 183,559 $ 12,756 $ 6,079,084 The following tables summarize an aging analysis of the loan portfolio by the time past due at March 31, 2019 and December 31, 2018 : (Dollars in thousands) 30 Days 60 Days 90+ Days Non-accrual Current Total As of March 31, 2019: Loans: Multifamily residential $ 1,440 $ — $ — $ 557 $ 3,745,719 $ 3,747,716 Single family residential 9,397 — — 949 2,131,643 2,141,989 Commercial real estate — — — — 190,082 190,082 Land, construction and NM — — — — 13,288 13,288 Total $ 10,837 $ — $ — $ 1,506 $ 6,080,732 $ 6,093,075 As of December 31, 2018: Loans: Multifamily residential $ — $ — $ — $ 566 $ 3,650,401 $ 3,650,967 Single family residential 357 2,205 — 1,598 2,227,642 2,231,802 Commercial real estate — — — — 183,559 183,559 Land, construction and NM — — — — 12,756 12,756 Total $ 357 $ 2,205 $ — $ 2,164 $ 6,074,358 $ 6,079,084 The following table summarizes information related to impaired loans at March 31, 2019 and December 31, 2018 : As of March 31, 2019 As of December 31, 2018 (Dollars in thousands) Recorded Investment Unpaid Principal Balance Related Allowance Recorded Investment Unpaid Principal Balance Related Allowance With no related allowance recorded: Multifamily residential $ 557 $ 631 $ — $ 566 $ 635 $ — Single family residential 3,535 3,772 — 5,075 5,333 — 4,092 4,403 — 5,641 5,968 — With an allowance recorded: Single family residential 926 926 25 933 933 25 926 926 25 933 933 25 Total: Multifamily residential 557 631 — 566 635 — Single family residential 4,461 4,698 25 6,008 6,266 25 $ 5,018 $ 5,329 $ 25 $ 6,574 $ 6,901 $ 25 The following table summarizes information related to impaired loans for the three months ended March 31, 2019 and 2018 : Three Months Ended March 31, 2019 2018 (Dollars in thousands) Average Recorded Investment Interest Income Cash Basis Interest Average Recorded Investment Interest Income Cash Basis Interest With no related allowance recorded: Multifamily residential $ 560 $ 3 $ 3 $ 2,070 $ — $ — Single family residential 4,148 36 — 8,165 37 — Commercial real estate — — — 487 — — 4,708 39 3 10,722 37 — With an allowance recorded: Single family residential 929 12 — 1,718 17 — 929 12 — 1,718 17 — Total: Multifamily residential 560 3 3 2,070 — — Single family residential 5,077 48 — 9,883 54 — Commercial real estate — — — 487 — — $ 5,637 $ 51 $ 3 $ 12,440 $ 54 $ — The following table summarizes the recorded investment related to troubled debt restructurings at March 31, 2019 and December 31, 2018 : (Dollars in thousands) March 31, December 31, Troubled debt restructurings: Single family residential $ 3,512 $ 4,410 The Company has allocated $25 thousand of allowances for loans modified in troubled debt restructurings at both March 31, 2019 and December 31, 2018 . The Company does not have commitments to lend additional funds to borrowers with loans whose terms have been modified in troubled debt restructurings. There were no new troubled debt restructurings during the three months ended March 31, 2019 and 2018 . The Company had no troubled debt restructurings with a subsequent payment default within twelve months following the modification during the three months ended March 31, 2019 and 2018 . A loan is considered to be in payment default once it is 90 days contractually past due under the modified terms.

NONPERFORMING ASSETS

NONPERFORMING ASSETS	3 Months Ended
	Mar. 31, 2019
Receivables [Abstract]
NONPERFORMING ASSETS	NONPERFORMING ASSETS Nonperforming assets include nonperforming loans plus real estate owned. The Company’s nonperforming assets at March 31, 2019 and December 31, 2018 are indicated below: (Dollars in thousands) March 31, December 31, Non-accrual loans: Multifamily residential $ 557 $ 566 Single family residential 949 1,598 Total non-accrual loans 1,506 2,164 Real estate owned — — Total nonperforming assets $ 1,506 $ 2,164 Interest income is subsequently recognized on a cash basis as long as the remaining unpaid principal amount of a non-accrual loan is deemed to be fully collectible. If there’s doubt regarding the collectability of the loan, then any interest payments received are applied to principal. Interest income was recognized on a cash basis on two non-accrual loans during the three months ended March 31, 2019 totaling $3 thousand . No interest income was recognized on non-accrual loans during the three months ended March 31, 2018 . Contractual interest not accrued on nonperforming loans during the three months ended March 31, 2019 and 2018 totaled $22 thousand and $90 thousand , respectively. Generally, nonperforming loans are considered impaired, because the repayment of the loan will not be made in accordance w ith the original contractual agreement.

MORTGAGE SERVICING RIGHTS

MORTGAGE SERVICING RIGHTS	3 Months Ended
	Mar. 31, 2019
Transfers and Servicing [Abstract]
MORTGAGE SERVICING RIGHTS	MORTGAGE SERVICING RIGHTS Servicing loans for others generally consists of collecting mortgage payments, maintaining escrow accounts, disbursing payments to investors, and conducting foreclosure proceedings. Loan servicing income is recorded on the accrual basis and includes servicing fees from investors and certain charges collected from borrowers. Mortgage loans serviced for others are not reported as assets. The principal balances of these loans are as follows: (Dollars in thousands) March 31, December 31, Mortgage loans serviced for: Federal Home Loan Mortgage Corporation ("Freddie Mac") $ 490,744 $ 497,950 Other financial institutions 185,896 139,558 Total mortgage loans serviced for others $ 676,640 $ 637,508 Included in the table above are $33.4 million of single family loans that were sold during the quarter ended March 31, 2019. In connection with the sale, the Company agreed to service this portfolio for a temporary period of 30 days . Following this period, the Company will release the servicing rights to the purchaser of this portfolio. Custodi al account balances maintained in connection with serviced loans totaled $948 thousand and $10.1 million at March 31, 2019 and December 31, 2018 , respectively. Activity for mortgage servicing rights are as follows: Three Months Ended March 31, (Dollars in thousands) 2019 2018 Beginning balance $ 3,463 $ 4,255 Additions 155 — Disposals — — Change in fair value due to changes in assumptions — — Other changes in fair value (146 ) (131 ) Ending balance $ 3,472 $ 4,124 Fair value as of March 31, 2019 was determined using a discount rate of 10% , prepayment speeds ranging from 5.8% to 82.0% , depending on the stratification of the specific right, and a weighted average default rate of 5% . The weighted average prepayment speed at March 31, 2019 was 22.6% . Fair value as of December 31, 2018 was determined using a discount rate of 10% , prepayment speeds ranging from 6.0% to 70.4% , depending on the stratification of the specific right, and a weighted average default rate of 5% . The weighted average prepayment speed at December 31, 2018 was 23.3% .

DEPOSITS

DEPOSITS	3 Months Ended
	Mar. 31, 2019
Banking and Thrift [Abstract]
DEPOSITS	DEPOSITS A summary of deposits at March 31, 2019 and December 31, 2018 is as follows: (Dollars in thousands) March 31, December 31, Certificates of deposit $ 3,523,187 $ 3,297,433 Money market savings 1,174,786 1,335,246 Interest bearing demand 216,580 179,272 Money market checking 127,351 123,119 Non-interest bearing demand 39,927 65,970 Total $ 5,081,831 $ 5,001,040 The Company had certificates of deposit with a denomination of $100 thousand or more totaling $2.5 billion and $2.4 billion at March 31, 2019 and December 31, 2018 , respectively. The Company had certificates of deposit that meet or exceed the FDIC Insurance limit of $250 thousand of $1.3 billion and $1.2 billion at March 31, 2019 and December 31, 2018 , respectively. The Company utilizes brokered deposits as an additional source of funding. The Company had brokered deposits of $611.2 million and $467.5 million at March 31, 2019 and December 31, 2018 , respectively. Maturities of the Company’s certificates of deposit at March 31, 2019 are summarized as follows (dollars in thousands): April 1 - December 31, 2019 $ 1,966,800 Year ending December 31, 2020 1,222,219 Year ending December 31, 2021 278,890 Year ending December 31, 2022 50,184 Year ending December 31, 2023 5,094 Total $ 3,523,187

FEDERAL HOME LOAN BANK AND FEDE

FEDERAL HOME LOAN BANK AND FEDERAL RESERVE BANK ADVANCES	3 Months Ended
	Mar. 31, 2019
Banking and Thrift [Abstract]
FEDERAL HOME LOAN BANK AND FEDERAL RESERVE BANK ADVANCES	FEDERAL HOME LOAN BANK AND FEDERAL RESERVE BANK ADVANCES The Bank may borrow from the FHLB, on either a short-term or long-term basis, up to 40% of its assets provided that adequate collateral has been pledged. As of March 31, 2019 and December 31, 2018 , the Bank had pledged various mortgage loans totaling approximately $2.3 billion and $2.1 billion , respectively, as well as the FHLB stock held by the Bank to secure these borrowing arrangements. The Bank has access to the Loan and Discount Window of the Federal Reserve Bank of San Francisco ("FRB"). Advances under this window are subject to the Bank providing qualifying collateral. Various mortgage loans totaling approximately $423.1 million and $406.6 million as of March 31, 2019 and December 31, 2018 , respectively, secure this borrowing arrangement. There were no borrowings outstanding with the FRB as of March 31, 2019 and December 31, 2018 . The following table discloses the Bank’s outstanding advances from the FHLB of San Francisco: Outstanding Balances As of March 31, 2019 (Dollars in thousands) March 31, December 31, Minimum Interest Rate Maximum Interest Rate Weighted Average Rate Maturity Dates Fixed rate short-term $ 57,500 $ 166,000 2.60 % 2.60 % 2.60 % April 2019 Fixed rate long-term 952,125 877,132 1.05 % 7.69 % 2.31 % June 2019 to August 2032 Variable rate long-term 100,000 100,000 2.32 % 2.98 % 2.65 % April 2019 to January 2020 $ 1,109,625 $ 1,143,132 The Bank's available borrowing capacity based on pledged loans to the FRB and the FHLB totaled $840.9 million and $681.5 million at March 31, 2019 and December 31, 2018 , respectively. As of March 31, 2019 and December 31, 2018 , the Bank pledged as collateral a $62.6 million FHLB letter of credit related to our multifamily securitization reimbursement obligation. In addition, the Bank pledged as collateral a $5.5 million FHLB letter of credit in connection with a time deposit with the State of California Treasurer's Office at March 31, 2019 . Short-term borrowings are borrowings with original maturities of 90 days or less. During the three months ended March 31, 2019 , there was a maximum amount of short-term borrowings outstanding of $209.7 million and an average amount outstanding of $143.0 million with a weighted average interest rate of 2.57% . The following table summarizes principal payments over the next five years as of March 31, 2019 (dollars in thousands): April 1 - December 31, 2019 $ 332,500 Year ending December 31, 2020 150,000 Year ending December 31, 2021 150,600 Year ending December 31, 2022 75,000 Year ending December 31, 2023 400,750 Thereafter 775 $ 1,109,625

JUNIOR SUBORDINATED DEFERRABLE

JUNIOR SUBORDINATED DEFERRABLE INTEREST DEBENTURES	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
JUNIOR SUBORDINATED DEFERRABLE INTEREST DEBENTURES	JUNIOR SUBORDINATED DEFERRABLE INTEREST DEBENTURES The Company formed two wholly-owned trust companies (the ‘‘Trusts’’) which issued guaranteed preferred beneficial interests (the "Trust Securities") in the Company’s junior subordinated deferrable interest debentures (the "Notes"). The Company is not considered the primary beneficiary of the Trusts and therefore, the Trusts are not consolidated in the Company’s financial statements, but rather the junior subordinated debentures are shown as a liability. The Company’s investment in the common securities of the Trusts, totaling $1.9 million , is included in other assets on the unaudited consolidated statements of financial condition. The sole asset of the Trusts are the Notes that they hold. The Trusts have invested the proceeds of such Trust Securities in the Notes. Each of the Notes has an interest rate equal to the corresponding Trust Securities distribution rate. The Company has the right to defer payment of interest on the Notes at any time or from time to time for a period not exceeding five years provided that no extension period may extend beyond the stated maturity of the relevant Notes. During any such extension period, distributions on the Trust Securities will also be deferred, and the Company’s ability to pay dividends on its common stock will be restricted. The Company has entered into contractual arrangements which, taken collectively, fully and unconditionally guarantee payment of: (i) accrued and unpaid distributions required to be paid on the Trust Securities; (ii) the redemption price with respect to any Trust Securities called for redemption by the Trusts; and (iii) payments due upon a voluntary or involuntary dissolution, winding up or liquidation of the Trusts. The Trust Securities are mandatorily redeemable upon maturity of the Notes, or upon earlier redemption as provided in the indenture. The Company has the right to redeem the Notes purchased by the Trusts, in whole or in part, on or after the redemption date. As specified in the indenture, if the Notes are redeemed prior to maturity, the redemption price will be the principal amount and any accrued but unpaid interest. The following table is a summary of the outstanding Trust Securities and Notes at March 31, 2019 and December 31, 2018 (dollars in thousands): March 31, 2019 December 31, 2018 Date Maturity Rate Index Issuer Amount Rate Amount Rate Issued Date (Quarterly Reset) Luther Burbank Statutory Trust I $ 41,238 3.99 % $ 41,238 4.17 % 3/1/2006 6/15/2036 3 month LIBOR + 1.38% Luther Burbank Statutory Trust II $ 20,619 4.23 % $ 20,619 4.41 % 3/1/2007 6/15/2037 3 month LIBOR + 1.62%

SENIOR DEBT

SENIOR DEBT	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
SENIOR DEBT	SENIOR DEBT In September 2014, the Company issued $95 million in senior unsecured term notes to qualified institutional investors. The following table summarizes information on these notes as of March 31, 2019 and December 31, 2018 : March 31, 2019 December 31, 2018 (Dollars in thousands) Principal Unamortized Debt Issuance Costs Principal Unamortized Debt Issuance Costs Maturity Date Fixed Interest Rate Senior Unsecured Term Notes $ 95,000 $ 676 $ 95,000 $ 707 9/30/2024 6.50 %

STOCK BASED COMPENSATION

STOCK BASED COMPENSATION	3 Months Ended
	Mar. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
STOCK BASED COMPENSATION	STOCK BASED COMPENSATION The Company’s stock based compensation consists of restricted stock awards ("RSAs") and restricted stock units ("RSUs") granted under the Luther Burbank Corporation Omnibus Equity and Incentive Compensation Plan ("Omnibus Plan"). In connection with its initial public offering ("IPO") in December 2017, the Company granted RSAs and RSUs to employees and nonemployee directors which all vest ratably over three years. At the same time, the Company granted RSUs in exchange for unvested phantom stock awards held by employees and all vested and unvested phantom stock awards held by nonemployee directors on a per share basis. The RSUs were subjected to the same vesting schedule and deferral elections that existed for the original phantom stock awards. Awards granted subsequent to the IPO vest ratably over one year for nonemployee directors and ratably over three to four years for employees. All RSAs and RSUs were granted at the fair value of the common stock at the time of the award. The RSAs and RSUs are considered fixed awards as the number of shares and fair value are known at the date of grant and the fair value at the grant date is amortized over the vesting and/or service period. Non-cash stock compensation expense recognized for RSAs and RSUs for the three months ended March 31, 2019 and 2018 totaled $838 thousand and $1.0 million , respectively. The fair value of RSAs and RSUs that vested during the three months ended March 31, 2019 and 2018 totaled $5.7 million and $1.5 million , respectively. As of March 31, 2019 and December 31, 2018 , there was $6.3 million and $4.3 million of unrecognized compensation expense related to 758,182 and 985,869 unvested RSAs and RSUs, respectively. As of March 31, 2019 and December 31, 2018 , this expense is expected to be recognized over a weighted average period of 2.12 years and 1.91 years , respectively. As of March 31, 2019 and December 31, 2018 , 522,464 and 169,490 shares, respectively, of RSUs were vested and remain unsettled per the original deferral elections. The following table summarizes share information about restricted stock awards and restricted stock units: Three Months Ended March 31, 2019 2018 Number of Shares Weighted Average Grant Date Fair Value Number of Shares Weighted Average Grant Date Fair Value Beginning of the period balance 1,155,359 $ 10.97 1,319,700 $ 10.75 Shares granted 297,663 9.79 131,140 12.77 Shares settled (169,648 ) 11.43 (53,059 ) 10.75 Shares forfeited (2,728 ) 10.75 (1,400 ) 10.75 End of the period balance 1,280,646 $ 10.63 1,396,381 $ 10.94 Under its Omnibus Plan, the Company reserved 3,360,000 shares of common stock for new awards. At March 31, 2019 and December 31, 2018 , there were 2,287,025 and 2,581,960 shares, respectively, of common stock reserved and available for grant through restricted stock or other awards under the Omnibus Plan.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS Fair Value Measurements Fair Value Hierarchy The Company groups its assets and liabilities measured at fair value in three levels, based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine fair value. Valuations within these levels are based upon: Level 1 - Quoted market prices for identical instruments traded in active exchange markets. Level 2 - Quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation techniques for which all significant assumptions are observable or can be corroborated by observable market data. Level 3 - Model-based techniques that use at least one significant assumption not observable in the market. These unobservable assumptions reflect the Company’s estimates of assumptions that market participants would use on pricing the asset or liability. Valuation techniques include management judgment and estimation which may be significant. Because broadly traded markets do not exist for most of the Company’s financial instruments, the fair value calculations attempt to incorporate the effect of current market conditions at a specific time. These determinations are subjective in nature, involve uncertainties and matters of significant judgment and do not include tax ramifications; therefore, the results cannot be determined with precision, substantiated by comparison to independent markets and may not be realized in an actual sale or immediate settlement of the instruments. There may be inherent weaknesses in any calculation technique, and changes in the underlying assumptions used, including discount rates and estimates of future cash flows, could significantly affect the results. For all of these reasons, the aggregation of the fair value calculations presented herein do not represent, and should not be construed to represent, the underlying value of the Company. Management monitors the availability of observable market data to assess the appropriate classification of assets and liabilities within the fair value hierarchy. Changes in economic conditions or model-based valuation techniques may require the transfer of financial instruments from one fair value level to another. In such instances, the transfer is reported at the beginning of the reporting period. Management evaluates the significance of transfers between levels based upon the nature of the financial instrument and size of the transfer relative to total assets, total liabilities, or total earnings. The following methods and assumptions were used to estimate the fair value of financial instruments: For cash and cash equivalents, accrued interest receivable and payable, demand deposits and short-term borrowings, the carrying amount is estimated to be fair value. The fair value of accrued interest receivable/payable balances are determined using inputs and fair value measurements commensurate with the asset or liability from which the accrued interest is generated. Fair values for available for sale and held to maturity debt securities, which include primarily debt securities issued by U.S. government sponsored agencies, are based on quoted market prices for similar securities. Fair values for equity securities, which consist of investments in the CRA Qualified Investment Fund are based on quoted market prices for similar securities. Loans are valued using the exit price notion. The fair value is estimated using market quotes for similar assets or the present value of future cash flows, discounted using a market rate for similar products and giving consideration to estimated prepayment risk and credit risk. The fair value of loans is determined utilizing estimates resulting in a Level 3 classification. Impaired loans are measured for impairment based on the present value of expected future cash flows discounted at the loans' effective interest rate, except that as a practical expedient, the Company may measure impairment based on a loan’s observable market price, or the fair value of the collateral (net of estimated costs to sell) if the loan is collateral dependent. The fair value of impaired loans is determined utilizing estimates resulting in a Level 3 classification. It was not practicable to determine the fair value of F HLB stock due to restrictions placed on its transferability. The fair value of servicing rights is determined using a valuation model that utilizes interest rate, prepayment speed, and default rate assumptions that market participants would use in estimating future net servicing income and that can be validated against available market data. The fair values of derivatives are based on valuation models using observable market data as of the measurement date. Fair values for fixed-rate certificates of deposit are estimated using discounted cash flow analyses using interest rates offered at each reporting date by the Company for certificates with similar remaining maturities. For deposits with no contractual maturity, the fair value is assumed to equal the carrying value. The fair value of FHLB advances is estimated based on discounting the future cash flows using the market rate currently offered for similar terms. The fair value of subordinated debentures is based on an indication of value provided by a third-party broker. For senior debt, the fair value is based on an indication of value provided by a third-party broker. Fair Value of Financial Instruments The carrying and estimated fair values of the Company’s financial instruments are as follows: Fair Level Measurements Using (Dollars in thousands) Carrying Amount Fair Value Level 1 Level 2 Level 3 As of March 31, 2019: Financial assets: Cash and cash equivalents $ 104,575 $ 104,575 $ 104,575 $ — $ — Debt securities: Available for sale 638,795 638,795 986 637,809 — Held to maturity 11,450 11,376 — 11,376 — Equity securities 11,582 11,582 — 11,582 — Loans receivable, net 6,109,576 6,130,635 — — 6,130,635 Accrued interest receivable 21,292 21,292 24 1,797 19,471 FHLB stock 32,047 N/A N/A N/A N/A Financial liabilities: Deposits $ 5,081,831 $ 5,086,375 $ 1,558,644 $ 3,527,731 $ — FHLB advances 1,109,625 1,118,110 — 1,118,110 — Junior subordinated deferrable interest debentures 61,857 57,481 — 57,481 — Senior debt 94,324 99,268 — 99,268 — Accrued interest payable 5,476 5,476 — 5,476 — As of December 31, 2018: Financial assets: Cash and cash equivalents $ 91,697 $ 91,697 $ 91,697 $ — $ — Debt securities: Available for sale 608,528 608,528 976 607,552 — Held to maturity 11,860 11,625 — 11,625 — Equity securities 11,438 11,438 — 11,438 — Loans receivable, net 6,096,316 6,092,885 — — 6,092,885 Accrued interest receivable 20,220 20,220 62 1,739 18,419 FHLB stock 31,823 N/A N/A N/A N/A Financial liabilities: Deposits $ 5,001,040 $ 4,957,054 $ 1,703,607 $ 3,253,447 $ — FHLB advances 1,143,132 1,144,326 — 1,144,326 — Junior subordinated deferrable interest debentures 61,857 56,596 — 56,596 — Senior debt 94,293 99,673 — 99,673 — Accrued interest payable 4,307 4,307 — 4,307 — These estimates do not reflect any premium or discount that could result from offering the Company’s entire holdings of a particular financial instrument for sale at one time, nor do they attempt to estimate the value of anticipated future business related to the instruments. In addition, the tax ramifications related to the realization of unrealized gains and losses can have a significant effect on fair value estimates and have not been considered in any of these estimates. Assets and Liabilities Recorded at Fair Value The following tables present information about the Company’s assets and liabilities measured at fair value on a recurring and nonrecurring basis as of March 31, 2019 and December 31, 2018 . Recurring Basis The Company is required or permitted to record the following assets and liabilities at fair value on a recurring basis (dollars in thousands): Description Fair Value Level 1 Level 2 Level 3 As of March 31, 2019: Financial Assets: Available for sale debt securities: Government and Government Sponsored Entities: Residential MBS and CMOs $ 179,804 $ — $ 179,804 $ — Commercial MBS and CMOs 324,774 — 324,774 — Agency bonds 133,231 — 133,231 — U.S. Treasury 986 986 — — Total available for sale debt securities $ 638,795 $ 986 $ 637,809 $ — Equity securities $ 11,582 $ — $ 11,582 $ — Mortgage servicing rights $ 3,472 $ — $ — $ 3,472 As of December 31, 2018: Financial Assets: Available for sale debt securities: Government and Government Sponsored Entities: Residential MBS and CMOs $ 192,113 $ — $ 192,113 $ — Commercial MBS and CMOs 292,951 — 292,951 — Agency bonds 122,488 — 122,488 — U.S. Treasury 976 976 — — Total available for sale debt securities $ 608,528 $ 976 $ 607,552 $ — Equity securities $ 11,438 $ — $ 11,438 $ — Mortgage servicing rights $ 3,463 $ — $ — $ 3,463 There were no transfers between Level 1 and Level 2 during the three months ended March 31, 2019 and 2018 . Non-recurring Basis The Company may be required, from time to time, to measure certain assets and liabilities at fair value on a non-recurring basis. For the three months ended March 31, 2019 and 2018 , there were no assets or liabilities measured at fair value on a non-recurring basis. The company held no real estate owned at March 31, 2019 and December 31, 2018 .

VARIABLE INTEREST ENTITIES (VIE

VARIABLE INTEREST ENTITIES (VIE)	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
VARIABLE INTEREST ENTITIES (VIE)	VARIABLE INTEREST ENTITIES ("VIE") The Company is involved with VIEs through its loan securitization activities. The Company evaluated its association with VIEs for consolidation purposes. Specifically, a VIE is to be consolidated by its primary beneficiary, the entity that has both the power to direct the activities that most significantly impact the VIE and a variable interest that could potentially be significant to the VIE. A variable interest is a contractual, ownership or other interest whose value fluctuates with the changes in the value of the VIE's assets and liabilities. The assessment includes an evaluation of the Company's continuing involvement with the VIE and the nature and significance of its variable interests. Multifamily loan securitization With respect to the securitization transaction with Freddie Mac which settled September 27, 2017, the Company's variable interests reside with a reimbursement agreement entered into with Freddie Mac that obligates the Bank to reimburse Freddie Mac for any defaulted contractual principal and interest payments identified after the ultimate resolution of the defaulted loans. Such reimbursement obligations are not to exceed 10% of the original principal amount of the loans comprising the securitization pool. As part of the securitization transaction, the Bank released all servicing obligations and rights to Freddie Mac who was designated as the Master Servicer. As Master Servicer, Freddie Mac appointed the Bank with sub-servicing obligations, which include obligations to collect and remit payments of principal and interest, manage payments of taxes and insurance, and otherwise administer the underlying loans. The servicing of defaulted loans and foreclosed loans was assigned to a separate third party entity, independent of the Bank and Freddie Mac. Freddie Mac, in its capacity as Master Servicer, can terminate the Bank in its role as sub-servicer and direct such responsibilities accordingly. In evaluating the variable interests and continuing involvement in the VIE, the Company determined that it does not have the power to make significant decisions or direct the activities that most significantly impact the economic performance of the VIE's assets and liabilities. As sub-servicer of the loans, the Bank does not have the authority to make significant decisions that influence the value of the VIE's net assets and therefore, is not the primary beneficiary of the VIE. Therefore, the Company determined that the VIE associated with the multifamily securitization should not be included in the consolidated financial statements of the Bank. The Company believes its maximum exposure to loss as a result of involvement with the VIE associated with the securitization under the reimbursement agreement executed with Freddie Mac is 10% of the original principal amount of the loans comprising the securitization pool, or $62.6 million . The reserve for estimated losses with respect to the reimbursement obligation totaled $1.4 million as of both March 31, 2019 and December 31, 2018 , respectively, based upon an analysis of quantitative and qualitative data over the underlying loans included in the securitization pool. No disbursements have been made in connection with the reimbursement obligation.

LOAN SALE AND SECURITIZATION AC

LOAN SALE AND SECURITIZATION ACTIVITIES	3 Months Ended
	Mar. 31, 2019
Transfers and Servicing [Abstract]
LOAN SALE AND SECURITIZATION ACTIVITIES	LOAN SALE AND SECURITIZATION ACTIVITIES The Company sells originated and acquired loans as part of its business operations and overall management of liquidity, assets and liabilities, and financial performance. The transfer of loans is executed in securitization or sale transactions. With respect to sale transactions, the Company's continuing involvement may or may not include ongoing servicing responsibilities and general representations and warranties. With respect to securitization sales, the Company executed its first and only transaction on September 27, 2017 with Freddie Mac. The transaction involved the sale of $626 million in originated multifamily loans through a Freddie Mac sponsored transaction. The Company's continuing involvement includes sub-servicing responsibilities, general representations and warranties, and reimbursement obligations. As sub-servicer for Freddie Mac, the Bank is required to maintain a minimum net worth in accordance with GAAP of not less than $2.0 million . If Luther Burbank Savings’ capital were to fall below this threshold, Freddie Mac would have the authority to terminate and assume the Bank’s sub-servicing duties. At March 31, 2019 , the Bank’s net worth was $723.6 million . General representations and warranties associated with loan sales and securitization sales require the Bank to uphold various assertions that pertain to the underlying loans at the time of the transaction, including, but not limited to, compliance with relevant laws and regulations, absence of fraud, enforcement of liens, no environmental damages, and maintenance of relevant environmental insurance. Such representations and warranties are limited to those that do not meet the quality represented at the transaction date and do not pertain to a decline in value or future payment defaults. In circumstances where the Bank breaches its representations and warranties, the Bank would generally be required to cure such instances through a repurchase or substitution of the subject loan(s). With respect to the securitization transaction, the Bank also has continuing involvement through a reimbursement agreement executed with Freddie Mac. To the extent the ultimate resolution of defaulted loans results in contractual principal and interest payments that are deficient, the Bank is obligated to reimburse Freddie Mac for such amounts, not to exceed 10% of the original principal amount of the loans comprising the securitization pool at the closing date of September 27, 2017. The following table provides cash flows associated with the Company's loan sale activities: Three Months Ended March 31, (Dollars in thousands) 2019 2018 Proceeds from loan sales $ 53,772 $ 24,691 Servicing fees 332 108 The following table provides information about the loans transferred through sales or securitization and not recorded on the unaudited consolidated statements of financial condition, for which the Company's continuing involvement includes sub-servicing or servicing responsibilities and/or reimbursement obligations: (Dollars in thousands) Single Family Residential Multifamily Residential As of March 31, 2019: Principal balance of loans $ 59,347 $ 617,293 Loans 90+ days past due — — Charge-offs, net — — As of December 31, 2018: Principal balance of loans 26,200 611,308 Loans 90+ days past due — — Charge-offs, net — — Included in the table above are $33.4 million of single family loans that were sold during the quarter ended March 31, 2019. In connection with the sale, the Company agreed to service this portfolio for a temporary period of approximately 30 days . Following this period, the Company released the servicing rights to the purchaser of this portfolio.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Financial Instruments With Off-Balance Sheet Risk The Company is a party to financial instruments with off-balance sheet risk in the normal course of business to meet the financing needs of its customers. These financial instruments represent commitments to originate fixed and variable rate loans and loans in process, and involve, to varying degrees, elements of interest rate risk and credit risk in excess of the amount recognized in the Company’s consolidated statements of financial condition. The Company’s exposure to credit loss in the event of nonperformance by the other party for commitments to extend credit and lines of credit is represented by the contractual amount of those instruments. The Company uses the same credit policies in making commitments to originate loans as it does for on-balance sheet instruments. Commitments to fund loans are agreements to lend to a customer as long as there is no violation of any condition established in the contract. Commitments generally have expiration dates or other termination clauses. In addition, external market forces may impact the probability of commitments being exercised; therefore, total commitments outstanding do not necessarily represent future cash requirements. At March 31, 2019 and December 31, 2018 , the Company had outstanding commitments of approximately $89.2 million and $70.9 million , respectively, for loans. Unfunded loan commitment reserves totaled $24 thousand and $52 thousand at March 31, 2019 and December 31, 2018 , respectively. Operating Leases The Company leases various office premises under long-term operating lease agreements. These leases expire between 2019 and 2029 , with certain leases containing either three , five or ten year renewal options. At March 31, 2019 , minimum commitments under these non-cancellable leases before considering renewal options are (dollars in thousands): April 1 - December 31, 2019 $ 3,965 Year ending December 31, 2020 3,952 Year ending December 31, 2021 3,484 Year ending December 31, 2022 2,526 Year ending December 31, 2023 1,257 Thereafter 1,289 Total $ 16,473 Rent expense under operating leases was $1.3 million for both the three months ended March 31, 2019 and 2018 . Sublease income earned was $177 thousand and $201 thousand for the three months ended March 31, 2019 and 2018 , respectively. Contingencies At present, there are no pending or threatened proceedings against the Company which, if determined adversely, would have a material effect on the Company’s business, financial position, results of operations, cash flows or stock price. In the ordinary course of operations, the Company may be party to various legal proceedings. Correspondent Banking Agreements The Company maintains funds on deposit with other federally insured financial institutions under correspondent banking agreements. These balances are insured by the FDIC up to $250 thousand. At March 31, 2019 and December 31, 2018 , the Company had $1.1 million and $736 thousand , respectively, in cash balances exceeding the insured amounts.

NATURE OF OPERATIONS (Policies)

NATURE OF OPERATIONS (Policies)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Basis of Accounting	Basis of Presentation The accompanying unaudited consolidated financial statements have been prepared in accordance with the instructions to Form 10-Q and, therefore, do not include all footnotes as would be necessary for a fair presentation of financial position, results of operations and comprehensive income, changes in stockholders’ equity and cash flows in conformity with accounting principles generally accepted in the United States of America (“GAAP”). However, these interim unaudited consolidated financial statements reflect all adjustments (consisting solely of normal recurring adjustments and accruals) which, in the opinion of management, are necessary for a fair presentation of financial position, results of operations and comprehensive income, changes in stockholders’ equity and cash flows for the interim periods presented. These unaudited consolidated financial statements have been prepared on a basis consistent with, and should be read in conjunction with, the audited consolidated financial statements as of and for the year ended December 31, 2018 , and the notes thereto, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018 filed with the SEC, under the Securities and Exchange Act of 1934, (the “Exchange Act”). The unaudited consolidated financial statements include the accounts of the Company and its subsidiaries. All intercompany accounts and transactions have been eliminated. The results of operations for the three months ended March 31, 2019 are not necessarily indicative of the results of operations that may be expected for any other interim period or for the year ending December 31, 2019 . The Company’s accounting and reporting policies conform to GAAP and to general practices within the banking industry.
Use of Estimates	Use of Estimates Management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the unaudited consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. These estimates and assumptions affect the amounts reported in the unaudited consolidated financial statements and the disclosures provided, and actual results could differ.
Earnings Per Share	Earnings Per Share ("EPS") Basic earnings per common share represents the amount of earnings for the period available to each share of common stock outstanding during the reporting period. Basic EPS is computed based upon net income divided by the weighted average number of common shares outstanding during the year. In determining the weighted average number of shares outstanding, vested restricted stock units are included. Diluted EPS represents the amount of earnings for the period available to each share of common stock outstanding including common stock that would have been outstanding assuming the issuance of common shares for all dilutive potential common shares outstanding during each reporting period. Diluted EPS is computed based upon net income divided by the weighted average number of common shares outstanding during each period, adjusted for the effect of dilutive potential common shares, such as restricted stock awards and units, calculated using the treasury stock method. (Dollars in thousands, except per share amounts) Three Months Ended March 31, 2019 2018 Net income $ 12,010 $ 11,102 Weighted average basic common shares outstanding 56,519,809 56,190,970 Add: Dilutive effects of assumed vesting of restricted stock 202,887 564,184 Weighted average diluted common shares outstanding 56,722,696 56,755,154 Income per common share: Basic EPS $ 0.21 $ 0.20 Diluted EPS $ 0.21 $ 0.20 Anti-dilutive shares not included in calculation of diluted earnings per share 13,981 —
New Financial Accounting Standards	New Financial Accounting Standards FASB ASU 2016-01 In January 2016, the FASB issued ASU 2016-01 which provided guidance to enhance the reporting model for financial instruments to provide users of financial statements with more decision-useful information. This update contains several provisions, including but not limited to (1) requiring equity investments, with certain exceptions, to be measured at fair value with changes in fair value recognized in net income; (2) simplifying the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; (3) eliminating the requirement to disclose the method(s) and significant assumptions used to estimate fair value; and (4) requiring separate presentation of financial assets and liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements. The update also changes certain financial statement disclosure requirements, including requiring disclosures of the fair value of financial instruments be made on the basis of exit price. The update was effective for public business entities ("PBEs") for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. As an emerging growth company, the Company was permitted to adopt this guidance on January 1, 2019 and, as a result, reclassified $399 thousand of unrealized losses on equity securities from other comprehensive income to retained earnings. Subsequent changes in the unrealized gain or loss on equity securities will be recorded through other noninterest income. Additionally, $11.4 million of equity securities were reclassified from available for sale securities to equity securities.
Fair Value Measurements	Fair Value Measurements Fair Value Hierarchy The Company groups its assets and liabilities measured at fair value in three levels, based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine fair value. Valuations within these levels are based upon: Level 1 - Quoted market prices for identical instruments traded in active exchange markets. Level 2 - Quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation techniques for which all significant assumptions are observable or can be corroborated by observable market data. Level 3 - Model-based techniques that use at least one significant assumption not observable in the market. These unobservable assumptions reflect the Company’s estimates of assumptions that market participants would use on pricing the asset or liability. Valuation techniques include management judgment and estimation which may be significant. Because broadly traded markets do not exist for most of the Company’s financial instruments, the fair value calculations attempt to incorporate the effect of current market conditions at a specific time. These determinations are subjective in nature, involve uncertainties and matters of significant judgment and do not include tax ramifications; therefore, the results cannot be determined with precision, substantiated by comparison to independent markets and may not be realized in an actual sale or immediate settlement of the instruments. There may be inherent weaknesses in any calculation technique, and changes in the underlying assumptions used, including discount rates and estimates of future cash flows, could significantly affect the results. For all of these reasons, the aggregation of the fair value calculations presented herein do not represent, and should not be construed to represent, the underlying value of the Company. Management monitors the availability of observable market data to assess the appropriate classification of assets and liabilities within the fair value hierarchy. Changes in economic conditions or model-based valuation techniques may require the transfer of financial instruments from one fair value level to another. In such instances, the transfer is reported at the beginning of the reporting period. Management evaluates the significance of transfers between levels based upon the nature of the financial instrument and size of the transfer relative to total assets, total liabilities, or total earnings. The following methods and assumptions were used to estimate the fair value of financial instruments: For cash and cash equivalents, accrued interest receivable and payable, demand deposits and short-term borrowings, the carrying amount is estimated to be fair value. The fair value of accrued interest receivable/payable balances are determined using inputs and fair value measurements commensurate with the asset or liability from which the accrued interest is generated. Fair values for available for sale and held to maturity debt securities, which include primarily debt securities issued by U.S. government sponsored agencies, are based on quoted market prices for similar securities. Fair values for equity securities, which consist of investments in the CRA Qualified Investment Fund are based on quoted market prices for similar securities. Loans are valued using the exit price notion. The fair value is estimated using market quotes for similar assets or the present value of future cash flows, discounted using a market rate for similar products and giving consideration to estimated prepayment risk and credit risk. The fair value of loans is determined utilizing estimates resulting in a Level 3 classification. Impaired loans are measured for impairment based on the present value of expected future cash flows discounted at the loans' effective interest rate, except that as a practical expedient, the Company may measure impairment based on a loan’s observable market price, or the fair value of the collateral (net of estimated costs to sell) if the loan is collateral dependent. The fair value of impaired loans is determined utilizing estimates resulting in a Level 3 classification. It was not practicable to determine the fair value of F HLB stock due to restrictions placed on its transferability. The fair value of servicing rights is determined using a valuation model that utilizes interest rate, prepayment speed, and default rate assumptions that market participants would use in estimating future net servicing income and that can be validated against available market data. The fair values of derivatives are based on valuation models using observable market data as of the measurement date. Fair values for fixed-rate certificates of deposit are estimated using discounted cash flow analyses using interest rates offered at each reporting date by the Company for certificates with similar remaining maturities. For deposits with no contractual maturity, the fair value is assumed to equal the carrying value. The fair value of FHLB advances is estimated based on discounting the future cash flows using the market rate currently offered for similar terms. The fair value of subordinated debentures is based on an indication of value provided by a third-party broker. For senior debt, the fair value is based on an indication of value provided by a third-party broker.

NATURE OF OPERATIONS (Tables)

NATURE OF OPERATIONS (Tables)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	(Dollars in thousands, except per share amounts) Three Months Ended March 31, 2019 2018 Net income $ 12,010 $ 11,102 Weighted average basic common shares outstanding 56,519,809 56,190,970 Add: Dilutive effects of assumed vesting of restricted stock 202,887 564,184 Weighted average diluted common shares outstanding 56,722,696 56,755,154 Income per common share: Basic EPS $ 0.21 $ 0.20 Diluted EPS $ 0.21 $ 0.20 Anti-dilutive shares not included in calculation of diluted earnings per share 13,981 —

INVESTMENT SECURITIES (Tables)

INVESTMENT SECURITIES (Tables)	3 Months Ended
	Mar. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Schedule of Debt Securities, Available-for-sale	The following tables summarize the amortized cost and the estimated fair value of available for sale debt securities as of the dates indicated: (Dollars in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value At March 31, 2019: Government and Government Sponsored Entities: Residential mortgage backed securities and collateralized mortgage obligations ("MBS and CMOs") $ 181,485 $ 197 $ (1,878 ) $ 179,804 Commercial MBS and CMOs 325,078 1,693 (1,997 ) 324,774 Agency bonds 135,102 26 (1,897 ) 133,231 U.S. Treasury 1,008 — (22 ) 986 Total available for sale debt securities $ 642,673 $ 1,916 $ (5,794 ) $ 638,795 At December 31, 2018: Government and Government Sponsored Entities: Residential MBS and CMOs $ 194,297 $ 339 $ (2,523 ) $ 192,113 Commercial MBS and CMOs 294,276 979 (2,304 ) 292,951 Agency bonds 125,329 7 (2,848 ) 122,488 U.S. Treasury 1,008 — (32 ) 976 Total available for sale debt securities $ 614,910 $ 1,325 $ (7,707 ) $ 608,528 December 31, 2018 Less than 12 Months 12 Months or More Total (Dollars in thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Government and Government Sponsored Entities: Residential MBS and CMOs $ 31,728 $ (304 ) $ 102,503 $ (2,219 ) $ 134,231 $ (2,523 ) Commercial MBS and CMOs 58,725 (432 ) 114,159 (1,872 ) 172,884 (2,304 ) Agency bonds 4,906 (18 ) 114,575 (2,830 ) 119,481 (2,848 ) U.S. Treasury — — 976 (32 ) 976 (32 ) Total available for sale debt securities $ 95,359 $ (754 ) $ 332,213 $ (6,953 ) $ 427,572 $ (7,707 ) The following tables summarize the gross unrealized losses and fair value of available for sale debt securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position: March 31, 2019 Less than 12 Months 12 Months or More Total (Dollars in thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Government and Government Sponsored Entities: Residential MBS and CMOs $ 43,757 $ (162 ) $ 108,121 $ (1,716 ) $ 151,878 $ (1,878 ) Commercial MBS and CMOs 35,400 (392 ) 149,246 (1,605 ) 184,646 (1,997 ) Agency bonds 14,607 (90 ) 115,598 (1,807 ) 130,205 (1,897 ) U.S. Treasury — — 986 (22 ) 986 (22 ) Total available for sale debt securities $ 93,764 $ (644 ) $ 373,951 $ (5,150 ) $ 467,715 $ (5,794 )
Schedule of Held-to-maturity Securities	The following tables summarize the amortized cost and estimated fair value of held to maturity investment securities as of the dates indicated: (Dollars in thousands) Amortized Cost Gross Unrecognized Gains Gross Unrecognized Losses Estimated Fair Value As of March 31, 2019: Government Sponsored Entities: Residential MBS $ 11,187 $ 40 $ (114 ) $ 11,113 Other investments 263 — — 263 Total held to maturity investment securities $ 11,450 $ 40 $ (114 ) $ 11,376 As of December 31, 2018: Government Sponsored Entities: Residential MBS $ 11,593 $ 27 $ (262 ) $ 11,358 Other investments 267 — — 267 Total held to maturity investment securities $ 11,860 $ 27 $ (262 ) $ 11,625 The following tables summarize the gross unrecognized losses and fair value of held to maturity investment securities, aggregated by investment category and length of time that individual securities have been in a continuous unrecognized loss position: Less than 12 Months 12 Months or More Total (Dollars in thousands) Fair Value Unrecognized Losses Fair Value Unrecognized Losses Fair Value Unrecognized Losses As of March 31, 2019: Government Sponsored Entities: Residential MBS $ — $ — $ 8,661 $ (114 ) $ 8,661 $ (114 ) As of December 31, 2018: Government Sponsored Entities: Residential MBS $ 6,481 $ (111 ) $ 3,739 $ (151 ) $ 10,220 $ (262 )
Schedule of Debt Maturities of Available-for-sale and Held-to-maturity Securities	The following table summarizes the scheduled maturities of available for sale and held to maturity investment securities as of March 31, 2019 : March 31, 2019 (Dollars in thousands) Amortized Cost Fair Value Available for sale debt securities One to five years $ 118,413 $ 116,584 Five to ten years 4,685 4,663 Beyond ten years 13,012 12,970 MBS and CMOs 506,563 504,578 Total available for sale debt securities $ 642,673 $ 638,795 Held to maturity investments securities Beyond ten years $ 263 $ 263 MBS 11,187 11,113 Total held to maturity debt securities $ 11,450 $ 11,376

LOANS (Tables)

LOANS (Tables)	3 Months Ended
	Mar. 31, 2019
Receivables [Abstract]
Schedule of Loans Receivable	Loans consist of the following: (Dollars in thousands) March 31, December 31, Permanent mortgages on: Multifamily residential $ 3,747,716 $ 3,650,967 Single family residential 2,141,989 2,231,802 Commercial real estate 190,082 183,559 Construction and land loans 13,188 12,656 Non-Mortgage (‘‘NM’’) loans 100 100 Total 6,093,075 6,079,084 Deferred loan costs, net 51,193 51,546 Allowance for loan losses (34,692 ) (34,314 ) Loans held for investment, net $ 6,109,576 $ 6,096,316
Schedule Allowance for Loan Losses	The following table summarizes activity in and the allocation of the allowance for loan losses by portfolio segment: (Dollars in thousands) Multifamily Residential Single Family Residential Commercial Real Estate Land, Construction and NM Total Three months ended March 31, 2019 Allowance for loan losses: Beginning balance allocated to portfolio segments $ 21,326 $ 10,125 $ 2,441 $ 422 $ 34,314 Provision for (reversal of) loan losses 720 (239 ) (163 ) (18 ) 300 Charge-offs — — — — — Recoveries — 3 — 75 78 Ending balance allocated to portfolio segments $ 22,046 $ 9,889 $ 2,278 $ 479 $ 34,692 Three months ended March 31, 2018 Allowance for loan losses: Beginning balance allocated to portfolio segments $ 18,588 $ 9,044 $ 1,734 $ 946 $ 30,312 Provision for loan losses 1,245 167 63 25 1,500 Charge-offs — — — — — Recoveries — 3 90 75 168 Ending balance allocated to portfolio segments $ 19,833 $ 9,214 $ 1,887 $ 1,046 $ 31,980 The following tables summarize the allocation of the allowance for loan losses by impairment methodology: (Dollars in thousands) Multifamily Residential Single Family Residential Commercial Real Estate Land, Construction and NM Total As of March 31, 2019: Ending allowance balance allocated to: Loans individually evaluated for impairment $ — $ 25 $ — $ — $ 25 Loans collectively evaluated for impairment 22,046 9,864 2,278 479 34,667 Ending balance $ 22,046 $ 9,889 $ 2,278 $ 479 $ 34,692 Loans: Ending balance: individually evaluated for impairment $ 557 $ 4,461 $ — $ — $ 5,018 Ending balance: collectively evaluated for impairment 3,747,159 2,137,528 190,082 13,288 6,088,057 Ending balance $ 3,747,716 $ 2,141,989 $ 190,082 $ 13,288 $ 6,093,075 As of December 31, 2018: Ending allowance balance allocated to: Loans individually evaluated for impairment $ — $ 25 $ — $ — $ 25 Loans collectively evaluated for impairment 21,326 10,100 2,441 422 34,289 Ending balance $ 21,326 $ 10,125 $ 2,441 $ 422 $ 34,314 Loans: Ending balance: individually evaluated for impairment $ 566 $ 6,008 $ — $ — $ 6,574 Ending balance: collectively evaluated for impairment 3,650,401 2,225,794 183,559 12,756 6,072,510 Ending balance $ 3,650,967 $ 2,231,802 $ 183,559 $ 12,756 $ 6,079,084
Schedule of Loan Portfolio by Internal Risk Indicators	The following tables summarize the loan portfolio allocated by management’s internal risk ratings at March 31, 2019 and December 31, 2018 : (Dollars in thousands) Multifamily Residential Single Family Residential Commercial Real Estate Land, Construction and NM Total As of March 31, 2019: Grade: Pass $ 3,681,125 $ 2,103,901 $ 186,242 $ 10,450 $ 5,981,718 Watch 58,340 20,839 3,840 — 83,019 Special mention 5,962 10,486 — 2,838 19,286 Substandard 2,289 6,763 — — 9,052 Total $ 3,747,716 $ 2,141,989 $ 190,082 $ 13,288 $ 6,093,075 As of December 31, 2018: Grade: Pass $ 3,581,468 $ 2,205,528 $ 180,190 $ 10,232 $ 5,977,418 Watch 64,958 20,288 1,887 — 87,133 Special mention 2,607 369 1,482 2,524 6,982 Substandard 1,934 5,617 — — 7,551 Total $ 3,650,967 $ 2,231,802 $ 183,559 $ 12,756 $ 6,079,084
Schedule or Past Due Loans Receivable	The following tables summarize an aging analysis of the loan portfolio by the time past due at March 31, 2019 and December 31, 2018 : (Dollars in thousands) 30 Days 60 Days 90+ Days Non-accrual Current Total As of March 31, 2019: Loans: Multifamily residential $ 1,440 $ — $ — $ 557 $ 3,745,719 $ 3,747,716 Single family residential 9,397 — — 949 2,131,643 2,141,989 Commercial real estate — — — — 190,082 190,082 Land, construction and NM — — — — 13,288 13,288 Total $ 10,837 $ — $ — $ 1,506 $ 6,080,732 $ 6,093,075 As of December 31, 2018: Loans: Multifamily residential $ — $ — $ — $ 566 $ 3,650,401 $ 3,650,967 Single family residential 357 2,205 — 1,598 2,227,642 2,231,802 Commercial real estate — — — — 183,559 183,559 Land, construction and NM — — — — 12,756 12,756 Total $ 357 $ 2,205 $ — $ 2,164 $ 6,074,358 $ 6,079,084
Schedule of Impaired Loans Receivables	The following table summarizes information related to impaired loans at March 31, 2019 and December 31, 2018 : As of March 31, 2019 As of December 31, 2018 (Dollars in thousands) Recorded Investment Unpaid Principal Balance Related Allowance Recorded Investment Unpaid Principal Balance Related Allowance With no related allowance recorded: Multifamily residential $ 557 $ 631 $ — $ 566 $ 635 $ — Single family residential 3,535 3,772 — 5,075 5,333 — 4,092 4,403 — 5,641 5,968 — With an allowance recorded: Single family residential 926 926 25 933 933 25 926 926 25 933 933 25 Total: Multifamily residential 557 631 — 566 635 — Single family residential 4,461 4,698 25 6,008 6,266 25 $ 5,018 $ 5,329 $ 25 $ 6,574 $ 6,901 $ 25 The following table summarizes information related to impaired loans for the three months ended March 31, 2019 and 2018 : Three Months Ended March 31, 2019 2018 (Dollars in thousands) Average Recorded Investment Interest Income Cash Basis Interest Average Recorded Investment Interest Income Cash Basis Interest With no related allowance recorded: Multifamily residential $ 560 $ 3 $ 3 $ 2,070 $ — $ — Single family residential 4,148 36 — 8,165 37 — Commercial real estate — — — 487 — — 4,708 39 3 10,722 37 — With an allowance recorded: Single family residential 929 12 — 1,718 17 — 929 12 — 1,718 17 — Total: Multifamily residential 560 3 3 2,070 — — Single family residential 5,077 48 — 9,883 54 — Commercial real estate — — — 487 — — $ 5,637 $ 51 $ 3 $ 12,440 $ 54 $ —
Schedule of Troubled Debt Restructurings	The following table summarizes the recorded investment related to troubled debt restructurings at March 31, 2019 and December 31, 2018 : (Dollars in thousands) March 31, December 31, Troubled debt restructurings: Single family residential $ 3,512 $ 4,410

NONPERFORMING ASSETS (Tables)

NONPERFORMING ASSETS (Tables)	3 Months Ended
	Mar. 31, 2019
Receivables [Abstract]
Schedule of Nonperforming Assets	The Company’s nonperforming assets at March 31, 2019 and December 31, 2018 are indicated below: (Dollars in thousands) March 31, December 31, Non-accrual loans: Multifamily residential $ 557 $ 566 Single family residential 949 1,598 Total non-accrual loans 1,506 2,164 Real estate owned — — Total nonperforming assets $ 1,506 $ 2,164

MORTGAGE SERVICING RIGHTS (Tabl

MORTGAGE SERVICING RIGHTS (Tables)	3 Months Ended
	Mar. 31, 2019
Transfers and Servicing [Abstract]
Schedule of Mortgage Loans Serviced for Others	The principal balances of these loans are as follows: (Dollars in thousands) March 31, December 31, Mortgage loans serviced for: Federal Home Loan Mortgage Corporation ("Freddie Mac") $ 490,744 $ 497,950 Other financial institutions 185,896 139,558 Total mortgage loans serviced for others $ 676,640 $ 637,508
Schedule of Changes in Servicing Assets	Activity for mortgage servicing rights are as follows: Three Months Ended March 31, (Dollars in thousands) 2019 2018 Beginning balance $ 3,463 $ 4,255 Additions 155 — Disposals — — Change in fair value due to changes in assumptions — — Other changes in fair value (146 ) (131 ) Ending balance $ 3,472 $ 4,124

DEPOSITS (Tables)

DEPOSITS (Tables)	3 Months Ended
	Mar. 31, 2019
Banking and Thrift [Abstract]
Schedule of Deposits	A summary of deposits at March 31, 2019 and December 31, 2018 is as follows: (Dollars in thousands) March 31, December 31, Certificates of deposit $ 3,523,187 $ 3,297,433 Money market savings 1,174,786 1,335,246 Interest bearing demand 216,580 179,272 Money market checking 127,351 123,119 Non-interest bearing demand 39,927 65,970 Total $ 5,081,831 $ 5,001,040
Schedule of Certificate Account Maturities	Maturities of the Company’s certificates of deposit at March 31, 2019 are summarized as follows (dollars in thousands): April 1 - December 31, 2019 $ 1,966,800 Year ending December 31, 2020 1,222,219 Year ending December 31, 2021 278,890 Year ending December 31, 2022 50,184 Year ending December 31, 2023 5,094 Total $ 3,523,187

FEDERAL HOME LOAN BANK AND FE_2

FEDERAL HOME LOAN BANK AND FEDERAL RESERVE BANK ADVANCES (Tables)	3 Months Ended
	Mar. 31, 2019
Banking and Thrift [Abstract]
Schedule of FHLB Advances	The following table discloses the Bank’s outstanding advances from the FHLB of San Francisco: Outstanding Balances As of March 31, 2019 (Dollars in thousands) March 31, December 31, Minimum Interest Rate Maximum Interest Rate Weighted Average Rate Maturity Dates Fixed rate short-term $ 57,500 $ 166,000 2.60 % 2.60 % 2.60 % April 2019 Fixed rate long-term 952,125 877,132 1.05 % 7.69 % 2.31 % June 2019 to August 2032 Variable rate long-term 100,000 100,000 2.32 % 2.98 % 2.65 % April 2019 to January 2020 $ 1,109,625 $ 1,143,132 The following table summarizes principal payments over the next five years as of March 31, 2019 (dollars in thousands): April 1 - December 31, 2019 $ 332,500 Year ending December 31, 2020 150,000 Year ending December 31, 2021 150,600 Year ending December 31, 2022 75,000 Year ending December 31, 2023 400,750 Thereafter 775 $ 1,109,625

JUNIOR SUBORDINATED DEFERRABL_2

JUNIOR SUBORDINATED DEFERRABLE INTEREST DEBENTURES (Tables)	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Schedule of Outstanding Trust Securities	The following table is a summary of the outstanding Trust Securities and Notes at March 31, 2019 and December 31, 2018 (dollars in thousands): March 31, 2019 December 31, 2018 Date Maturity Rate Index Issuer Amount Rate Amount Rate Issued Date (Quarterly Reset) Luther Burbank Statutory Trust I $ 41,238 3.99 % $ 41,238 4.17 % 3/1/2006 6/15/2036 3 month LIBOR + 1.38% Luther Burbank Statutory Trust II $ 20,619 4.23 % $ 20,619 4.41 % 3/1/2007 6/15/2037 3 month LIBOR + 1.62%

SENIOR DEBT (Tables)

SENIOR DEBT (Tables)	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Schedule of Debt	The following table summarizes information on these notes as of March 31, 2019 and December 31, 2018 : March 31, 2019 December 31, 2018 (Dollars in thousands) Principal Unamortized Debt Issuance Costs Principal Unamortized Debt Issuance Costs Maturity Date Fixed Interest Rate Senior Unsecured Term Notes $ 95,000 $ 676 $ 95,000 $ 707 9/30/2024 6.50 %

STOCK BASED COMPENSATION (Table

STOCK BASED COMPENSATION (Tables)	3 Months Ended
	Mar. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Restricted Stock Activity	The following table summarizes share information about restricted stock awards and restricted stock units: Three Months Ended March 31, 2019 2018 Number of Shares Weighted Average Grant Date Fair Value Number of Shares Weighted Average Grant Date Fair Value Beginning of the period balance 1,155,359 $ 10.97 1,319,700 $ 10.75 Shares granted 297,663 9.79 131,140 12.77 Shares settled (169,648 ) 11.43 (53,059 ) 10.75 Shares forfeited (2,728 ) 10.75 (1,400 ) 10.75 End of the period balance 1,280,646 $ 10.63 1,396,381 $ 10.94

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Assets and Liabilities	The carrying and estimated fair values of the Company’s financial instruments are as follows: Fair Level Measurements Using (Dollars in thousands) Carrying Amount Fair Value Level 1 Level 2 Level 3 As of March 31, 2019: Financial assets: Cash and cash equivalents $ 104,575 $ 104,575 $ 104,575 $ — $ — Debt securities: Available for sale 638,795 638,795 986 637,809 — Held to maturity 11,450 11,376 — 11,376 — Equity securities 11,582 11,582 — 11,582 — Loans receivable, net 6,109,576 6,130,635 — — 6,130,635 Accrued interest receivable 21,292 21,292 24 1,797 19,471 FHLB stock 32,047 N/A N/A N/A N/A Financial liabilities: Deposits $ 5,081,831 $ 5,086,375 $ 1,558,644 $ 3,527,731 $ — FHLB advances 1,109,625 1,118,110 — 1,118,110 — Junior subordinated deferrable interest debentures 61,857 57,481 — 57,481 — Senior debt 94,324 99,268 — 99,268 — Accrued interest payable 5,476 5,476 — 5,476 — As of December 31, 2018: Financial assets: Cash and cash equivalents $ 91,697 $ 91,697 $ 91,697 $ — $ — Debt securities: Available for sale 608,528 608,528 976 607,552 — Held to maturity 11,860 11,625 — 11,625 — Equity securities 11,438 11,438 — 11,438 — Loans receivable, net 6,096,316 6,092,885 — — 6,092,885 Accrued interest receivable 20,220 20,220 62 1,739 18,419 FHLB stock 31,823 N/A N/A N/A N/A Financial liabilities: Deposits $ 5,001,040 $ 4,957,054 $ 1,703,607 $ 3,253,447 $ — FHLB advances 1,143,132 1,144,326 — 1,144,326 — Junior subordinated deferrable interest debentures 61,857 56,596 — 56,596 — Senior debt 94,293 99,673 — 99,673 — Accrued interest payable 4,307 4,307 — 4,307 —
Schedule of Fair Value of Assets Measured on a Recurring Basis	The Company is required or permitted to record the following assets and liabilities at fair value on a recurring basis (dollars in thousands): Description Fair Value Level 1 Level 2 Level 3 As of March 31, 2019: Financial Assets: Available for sale debt securities: Government and Government Sponsored Entities: Residential MBS and CMOs $ 179,804 $ — $ 179,804 $ — Commercial MBS and CMOs 324,774 — 324,774 — Agency bonds 133,231 — 133,231 — U.S. Treasury 986 986 — — Total available for sale debt securities $ 638,795 $ 986 $ 637,809 $ — Equity securities $ 11,582 $ — $ 11,582 $ — Mortgage servicing rights $ 3,472 $ — $ — $ 3,472 As of December 31, 2018: Financial Assets: Available for sale debt securities: Government and Government Sponsored Entities: Residential MBS and CMOs $ 192,113 $ — $ 192,113 $ — Commercial MBS and CMOs 292,951 — 292,951 — Agency bonds 122,488 — 122,488 — U.S. Treasury 976 976 — — Total available for sale debt securities $ 608,528 $ 976 $ 607,552 $ — Equity securities $ 11,438 $ — $ 11,438 $ — Mortgage servicing rights $ 3,463 $ — $ — $ 3,463
Schedule of Fair Value of Liabilities Measured on a Recurring Basis	The Company is required or permitted to record the following assets and liabilities at fair value on a recurring basis (dollars in thousands): Description Fair Value Level 1 Level 2 Level 3 As of March 31, 2019: Financial Assets: Available for sale debt securities: Government and Government Sponsored Entities: Residential MBS and CMOs $ 179,804 $ — $ 179,804 $ — Commercial MBS and CMOs 324,774 — 324,774 — Agency bonds 133,231 — 133,231 — U.S. Treasury 986 986 — — Total available for sale debt securities $ 638,795 $ 986 $ 637,809 $ — Equity securities $ 11,582 $ — $ 11,582 $ — Mortgage servicing rights $ 3,472 $ — $ — $ 3,472 As of December 31, 2018: Financial Assets: Available for sale debt securities: Government and Government Sponsored Entities: Residential MBS and CMOs $ 192,113 $ — $ 192,113 $ — Commercial MBS and CMOs 292,951 — 292,951 — Agency bonds 122,488 — 122,488 — U.S. Treasury 976 976 — — Total available for sale debt securities $ 608,528 $ 976 $ 607,552 $ — Equity securities $ 11,438 $ — $ 11,438 $ — Mortgage servicing rights $ 3,463 $ — $ — $ 3,463

LOAN SALE AND SECURITIZATION _2

LOAN SALE AND SECURITIZATION ACTIVITIES (Tables)	3 Months Ended
	Mar. 31, 2019
Transfers and Servicing [Abstract]
Schedule of Cash Flows From Loan Sale Activities	The following table provides cash flows associated with the Company's loan sale activities: Three Months Ended March 31, (Dollars in thousands) 2019 2018 Proceeds from loan sales $ 53,772 $ 24,691 Servicing fees 332 108
Schedule of Loans Transfered Through Sale or Securitization	The following table provides information about the loans transferred through sales or securitization and not recorded on the unaudited consolidated statements of financial condition, for which the Company's continuing involvement includes sub-servicing or servicing responsibilities and/or reimbursement obligations: (Dollars in thousands) Single Family Residential Multifamily Residential As of March 31, 2019: Principal balance of loans $ 59,347 $ 617,293 Loans 90+ days past due — — Charge-offs, net — — As of December 31, 2018: Principal balance of loans 26,200 611,308 Loans 90+ days past due — — Charge-offs, net — —

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	3 Months Ended
	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Schedule of Operating Lease Maturities	At March 31, 2019 , minimum commitments under these non-cancellable leases before considering renewal options are (dollars in thousands): April 1 - December 31, 2019 $ 3,965 Year ending December 31, 2020 3,952 Year ending December 31, 2021 3,484 Year ending December 31, 2022 2,526 Year ending December 31, 2023 1,257 Thereafter 1,289 Total $ 16,473

NATURE OF OPERATIONS - Narrativ

NATURE OF OPERATIONS - Narrative (Details) $ in Thousands	Mar. 31, 2019branchoffice	Jan. 01, 2019USD ($)
Sonoma, Marin, Santa Clara, and Los Angeles Counties
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of full service branches | branch	9
King County, Washington
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of full service branches | branch	1
California
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of loan production offices | office	7
Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principal		$ 0
Accounting Standards Update 2016-01 | Accumulated Other Comprehensive (Loss) Income (Net of Taxes) Available for Sale Securities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principal		399
Accounting Standards Update 2016-01 | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principal		(399)
Debt Securities, Available-for-sale | Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principal		(11,400)
Equity Securities, FV-NI | Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principal		$ 11,400

NATURE OF OPERATIONS - Earnings

NATURE OF OPERATIONS - Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Accounting Policies [Abstract]
Net income	$ 12,010	$ 11,102
Weighted average common shares outstanding - basic (in shares)	56,519,809	56,190,970
Add: Dilutive effects of assumed vesting of restricted stock (in shares)	202,887	564,184
Weighted average common shares outstanding - diluted (in shares)	56,722,696	56,755,154
Basic earnings per common share (in usd per share)	$ 0.21	$ 0.20
Diluted earnings per common share (in usd per share)	$ 0.21	$ 0.20
Anti-dilutive shares not included in calculation of diluted earnings per share (in shares)	13,981	0

INVESTMENT SECURITIES - Availab

INVESTMENT SECURITIES - Available-for-sale Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 642,673	$ 614,910
Gross Unrealized Gains	1,916	1,325
Gross Unrealized Losses	(5,794)	(7,707)
Estimated Fair Value	638,795	608,528
Fair Value
Less than 12 Months	93,764	95,359
12 Months or More	373,951	332,213
Total	467,715	427,572
Unrealized Losses
Less than 12 Months	(644)	(754)
12 Months or More	(5,150)	(6,953)
Total	(5,794)	(7,707)
Residential mortgage backed securities and collateralized mortgage obligations (MBS and CMOs)
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	181,485	194,297
Gross Unrealized Gains	197	339
Gross Unrealized Losses	(1,878)	(2,523)
Estimated Fair Value	179,804	192,113
Fair Value
Less than 12 Months	43,757	31,728
12 Months or More	108,121	102,503
Total	151,878	134,231
Unrealized Losses
Less than 12 Months	(162)	(304)
12 Months or More	(1,716)	(2,219)
Total	(1,878)	(2,523)
Commercial MBS and CMOs
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	325,078	294,276
Gross Unrealized Gains	1,693	979
Gross Unrealized Losses	(1,997)	(2,304)
Estimated Fair Value	324,774	292,951
Fair Value
Less than 12 Months	35,400	58,725
12 Months or More	149,246	114,159
Total	184,646	172,884
Unrealized Losses
Less than 12 Months	(392)	(432)
12 Months or More	(1,605)	(1,872)
Total	(1,997)	(2,304)
Agency bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	135,102	125,329
Gross Unrealized Gains	26	7
Gross Unrealized Losses	(1,897)	(2,848)
Estimated Fair Value	133,231	122,488
Fair Value
Less than 12 Months	14,607	4,906
12 Months or More	115,598	114,575
Total	130,205	119,481
Unrealized Losses
Less than 12 Months	(90)	(18)
12 Months or More	(1,807)	(2,830)
Total	(1,897)	(2,848)
U.S. Treasury
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,008	1,008
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(22)	(32)
Estimated Fair Value	986	976
Fair Value
Less than 12 Months	0	0
12 Months or More	986	976
Total	986	976
Unrealized Losses
Less than 12 Months	0	0
12 Months or More	(22)	(32)
Total	$ (22)	$ (32)

INVESTMENT SECURITIES - Narrati

INVESTMENT SECURITIES - Narrative (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)security	Jan. 01, 2019USD ($)	Dec. 31, 2018USD ($)security	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Debt Securities, Available-for-sale [Line Items]
Unrealized loss on available-for-sale investment securities | $	$ 588,298		$ 581,145	$ 553,751	$ 549,745
Equity securities, at fair value | $	$ 11,582		$ 11,438
Residential mortgage backed securities and collateralized mortgage obligations (MBS and CMOs)
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, number of positions	80		82
Debt securities, available-for-sale, unrealized loss position, number of positions	56		45
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer, number of positions	39		40
Held-to-maturity securities, number of positions	7		7
Held-to-maturity securities, unrealized loss position, number of positions	4		6
Held-to-maturity securities, continuous unrealized loss position, 12 months or longer, number of positions	4		3
Commercial MBS and CMOs
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, number of positions	38		34
Debt securities, available-for-sale, unrealized loss position, number of positions	24		23
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer, number of positions	18		16
Agency bonds
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, number of positions	15		14
Debt securities, available-for-sale, unrealized loss position, number of positions	14		13
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer, number of positions			12
U.S. Treasury
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer, number of positions	1		1
CRA Qualified Investment Fund
Debt Securities, Available-for-sale [Line Items]
Equity securities, at fair value | $	$ 11,600		$ 11,400
Changes in fair value recognized in other noninterest income | $	144
Accounting Standards Update 2016-01
Debt Securities, Available-for-sale [Line Items]
Cumulative effect of change in accounting principal | $		$ 0
Accumulated Other Comprehensive (Loss) Income (Net of Taxes) Available for Sale Securities
Debt Securities, Available-for-sale [Line Items]
Unrealized loss on available-for-sale investment securities | $	(2,756)		(4,935)	(6,813)	(6,214)
Unrealized loss on available-for-sale investment securities tax asset | $	1,100		2,000
Accumulated Other Comprehensive (Loss) Income (Net of Taxes) Available for Sale Securities | Accounting Standards Update 2016-01
Debt Securities, Available-for-sale [Line Items]
Cumulative effect of change in accounting principal | $		399
Accumulated Other Comprehensive (Loss) Income (Net of Taxes) Available for Sale Securities | Accounting Standards Update 2016-01 | CRA Qualified Investment Fund
Debt Securities, Available-for-sale [Line Items]
Cumulative effect of change in accounting principal | $		399
Retained Earnings
Debt Securities, Available-for-sale [Line Items]
Unrealized loss on available-for-sale investment securities | $	$ 138,123		$ 129,806	$ 105,750	$ 102,459
Retained Earnings | Accounting Standards Update 2016-01
Debt Securities, Available-for-sale [Line Items]
Cumulative effect of change in accounting principal | $		$ (399)

INVESTMENT SECURITIES - Held-to

INVESTMENT SECURITIES - Held-to-maturity Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 11,450	$ 11,860
Gross Unrecognized Gains	40	27
Gross Unrecognized Losses	(114)	(262)
Estimated Fair Value	11,376	11,625
Residential mortgage backed securities and collateralized mortgage obligations (MBS and CMOs)
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	11,187	11,593
Gross Unrecognized Gains	40	27
Gross Unrecognized Losses	(114)	(262)
Estimated Fair Value	11,113	11,358
Fair Value
Less than 12 Months	0	6,481
12 Months or More	8,661	3,739
Total	8,661	10,220
Unrecognized Losses
Less than 12 Months	0	(111)
12 Months or More	(114)	(151)
Total	(114)	(262)
Other investments
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	263	267
Gross Unrecognized Gains	0	0
Gross Unrecognized Losses	0	0
Estimated Fair Value	$ 263	$ 267

INVESTMENT SECURITIES - Schedul

INVESTMENT SECURITIES - Schedule of Investment Securities Maturities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Amortized Cost
One to five years	$ 118,413
Five to ten years	4,685
Beyond ten years	13,012
Amortized Cost	642,673	$ 614,910
Fair Value
One to five years	116,584
Five to ten years	4,663
Beyond ten years	12,970
Fair Value	638,795	608,528
Amortized Cost
Held-to-maturity investment securities beyond ten years	263
Amortized Cost	11,450	11,860
Fair Value
Beyond ten years	263
Total held to maturity debt securities	11,376	$ 11,625
MBS and CMOs
Amortized Cost
MBS and CMOs	506,563
Fair Value
MBS and CMOs	504,578
MBS
Amortized Cost
MBS	11,187
Fair Value
MBS	$ 11,113

LOANS - Loans Receivable (Detai

LOANS - Loans Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable, before fees, gross	$ 6,093,075	$ 6,079,084
Deferred loan costs, net	51,193	51,546
Allowance for loan losses	(34,692)	(34,314)
Loans held for investment, net	6,109,576	6,096,316
Multifamily residential | Permanent mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable, before fees, gross	3,747,716	3,650,967
Single family residential | Permanent mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable, before fees, gross	2,141,989	2,231,802
Commercial real estate | Permanent mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable, before fees, gross	190,082	183,559
Construction and land loans | Permanent mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable, before fees, gross	13,188	12,656
Land, Construction and NM | Non-Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable, before fees, gross	$ 100	$ 100

LOANS - Allowance for Loan Loss

LOANS - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance allocated to portfolio segments	$ 34,314	$ 30,312
Provision for (reversal of) loan losses	300	1,500
Charge-offs	0	0
Recoveries	78	168
Ending balance allocated to portfolio segments	34,692	31,980
Ending allowance balance allocated to:
Loans individually evaluated for impairment			$ 25	$ 25
Loans collectively evaluated for impairment			34,667	34,289
Ending balance	34,314	30,312	34,692	34,314
Loans:
Ending balance: individually evaluated for impairment			5,018	6,574
Ending balance: collectively evaluated for impairment			6,088,057	6,072,510
Ending balance			6,093,075	6,079,084
Multifamily residential
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance allocated to portfolio segments	21,326	18,588
Provision for (reversal of) loan losses	720	1,245
Charge-offs	0	0
Recoveries	0	0
Ending balance allocated to portfolio segments	22,046	19,833
Ending allowance balance allocated to:
Loans individually evaluated for impairment			0	0
Loans collectively evaluated for impairment			22,046	21,326
Ending balance	21,326	18,588	22,046	21,326
Loans:
Ending balance: individually evaluated for impairment			557	566
Ending balance: collectively evaluated for impairment			3,747,159	3,650,401
Ending balance			3,747,716	3,650,967
Single family residential
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance allocated to portfolio segments	10,125	9,044
Provision for (reversal of) loan losses	(239)	167
Charge-offs	0	0
Recoveries	3	3
Ending balance allocated to portfolio segments	9,889	9,214
Ending allowance balance allocated to:
Loans individually evaluated for impairment			25	25
Loans collectively evaluated for impairment			9,864	10,100
Ending balance	10,125	9,044	9,889	10,125
Loans:
Ending balance: individually evaluated for impairment			4,461	6,008
Ending balance: collectively evaluated for impairment			2,137,528	2,225,794
Ending balance			2,141,989	2,231,802
Commercial real estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance allocated to portfolio segments	2,441	1,734
Provision for (reversal of) loan losses	(163)	63
Charge-offs	0	0
Recoveries	0	90
Ending balance allocated to portfolio segments	2,278	1,887
Ending allowance balance allocated to:
Loans individually evaluated for impairment			0	0
Loans collectively evaluated for impairment			2,278	2,441
Ending balance	2,441	1,734	2,278	2,441
Loans:
Ending balance: individually evaluated for impairment			0	0
Ending balance: collectively evaluated for impairment			190,082	183,559
Ending balance			190,082	183,559
Land, Construction and NM
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance allocated to portfolio segments	422	946
Provision for (reversal of) loan losses	(18)	25
Charge-offs	0	0
Recoveries	75	75
Ending balance allocated to portfolio segments	479	1,046
Ending allowance balance allocated to:
Loans individually evaluated for impairment			0	0
Loans collectively evaluated for impairment			479	422
Ending balance	$ 422	$ 946	479	422
Loans:
Ending balance: individually evaluated for impairment			0	0
Ending balance: collectively evaluated for impairment			13,288	12,756
Ending balance			$ 13,288	$ 12,756

LOANS - Portfolio Allocated by

LOANS - Portfolio Allocated by Internal Risk Ratings (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment [Line Items]
Total	$ 6,093,075	$ 6,079,084
Pass
Financing Receivable, Recorded Investment [Line Items]
Total	5,981,718	5,977,418
Watch
Financing Receivable, Recorded Investment [Line Items]
Total	83,019	87,133
Special mention
Financing Receivable, Recorded Investment [Line Items]
Total	19,286	6,982
Substandard
Financing Receivable, Recorded Investment [Line Items]
Total	9,052	7,551
Multifamily residential
Financing Receivable, Recorded Investment [Line Items]
Total	3,747,716	3,650,967
Multifamily residential | Pass
Financing Receivable, Recorded Investment [Line Items]
Total	3,681,125	3,581,468
Multifamily residential | Watch
Financing Receivable, Recorded Investment [Line Items]
Total	58,340	64,958
Multifamily residential | Special mention
Financing Receivable, Recorded Investment [Line Items]
Total	5,962	2,607
Multifamily residential | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total	2,289	1,934
Single family residential
Financing Receivable, Recorded Investment [Line Items]
Total	2,141,989	2,231,802
Single family residential | Pass
Financing Receivable, Recorded Investment [Line Items]
Total	2,103,901	2,205,528
Single family residential | Watch
Financing Receivable, Recorded Investment [Line Items]
Total	20,839	20,288
Single family residential | Special mention
Financing Receivable, Recorded Investment [Line Items]
Total	10,486	369
Single family residential | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total	6,763	5,617
Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total	190,082	183,559
Commercial real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Total	186,242	180,190
Commercial real estate | Watch
Financing Receivable, Recorded Investment [Line Items]
Total	3,840	1,887
Commercial real estate | Special mention
Financing Receivable, Recorded Investment [Line Items]
Total	0	1,482
Commercial real estate | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total	0	0
Land, Construction and NM
Financing Receivable, Recorded Investment [Line Items]
Total	13,288	12,756
Land, Construction and NM | Pass
Financing Receivable, Recorded Investment [Line Items]
Total	10,450	10,232
Land, Construction and NM | Watch
Financing Receivable, Recorded Investment [Line Items]
Total	0	0
Land, Construction and NM | Special mention
Financing Receivable, Recorded Investment [Line Items]
Total	2,838	2,524
Land, Construction and NM | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total	$ 0	$ 0

LOANS - Aging Analysis (Details

LOANS - Aging Analysis (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	$ 1,506	$ 2,164
Current	6,080,732	6,074,358
Ending balance	6,093,075	6,079,084
30 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	10,837	357
60 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	2,205
90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	0
Multifamily residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	557	566
Current	3,745,719	3,650,401
Ending balance	3,747,716	3,650,967
Multifamily residential | 30 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	1,440	0
Multifamily residential | 60 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	0
Multifamily residential | 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	0
Single family residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	949	1,598
Current	2,131,643	2,227,642
Ending balance	2,141,989	2,231,802
Single family residential | 30 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	9,397	357
Single family residential | 60 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	2,205
Single family residential | 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	0
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	0	0
Current	190,082	183,559
Ending balance	190,082	183,559
Commercial real estate | 30 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	0
Commercial real estate | 60 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	0
Commercial real estate | 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	0
Land, Construction and NM
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual	0	0
Current	13,288	12,756
Ending balance	13,288	12,756
Land, Construction and NM | 30 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	0
Land, Construction and NM | 60 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	0	0
Land, Construction and NM | 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	$ 0	$ 0

LOANS - Impaired Loans (Details

LOANS - Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Recorded Investment
With no related allowance recorded	$ 4,092		$ 5,641
With an allowance recorded	926		933
Total	5,018		6,574
Unpaid Principal Balance
With no related allowance recorded	4,403		5,968
With an allowance recorded	926		933
Total	5,329		6,901
Related Allowance	25		25
Average Recorded Investment
With no related allowance recorded	4,708	$ 10,722
With an allowance recorded	929	1,718
Total	5,637	12,440
Interest Income
With no related allowance recorded	39	37
With an allowance recorded	12	17
Total	51	54
Cash Basis Interest
With no related allowance recorded	3	0
With an allowance recorded	0	0
Total	3	0
Multifamily residential
Recorded Investment
With no related allowance recorded	557		566
Total	557		566
Unpaid Principal Balance
With no related allowance recorded	631		635
Total	631		635
Related Allowance	0		0
Average Recorded Investment
With no related allowance recorded	560	2,070
Total	560	2,070
Interest Income
With no related allowance recorded	3	0
Total	3	0
Cash Basis Interest
With no related allowance recorded	3	0
Total	3	0
Single family residential
Recorded Investment
With no related allowance recorded	3,535		5,075
With an allowance recorded	926		933
Total	4,461		6,008
Unpaid Principal Balance
With no related allowance recorded	3,772		5,333
With an allowance recorded	926		933
Total	4,698		6,266
Related Allowance	25		$ 25
Average Recorded Investment
With no related allowance recorded	4,148	8,165
With an allowance recorded	929	1,718
Total	5,077	9,883
Interest Income
With no related allowance recorded	36	37
With an allowance recorded	12	17
Total	48	54
Cash Basis Interest
With no related allowance recorded	0	0
With an allowance recorded	0	0
Total	0	0
Commercial real estate
Average Recorded Investment
With no related allowance recorded	0	487
Total	0	487
Interest Income
With no related allowance recorded	0	0
Total	0	0
Cash Basis Interest
With no related allowance recorded	0	0
Total	$ 0	$ 0

LOANS - Troubled Debt Restructu

LOANS - Troubled Debt Restructurings (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Modifications [Line Items]
Related Allowance	$ 25	$ 25
Single family residential
Financing Receivable, Modifications [Line Items]
Total recorded investment	3,512	4,410
Related Allowance	$ 25	$ 25

NONPERFORMING ASSETS (Details)

NONPERFORMING ASSETS (Details)	3 Months Ended
	Mar. 31, 2019USD ($)loan	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	$ 1,506,000		$ 2,164,000
Real estate owned	0		0
Total nonperforming assets	$ 1,506,000		2,164,000
Number of non-accrual loans with interest income recognized | loan	2
Interest income recognized on non-accrual loans	$ 3,000	$ 0
Contractual interest not accrued during the quarter	22,000	$ 90,000
Multifamily residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	557,000		566,000
Single family residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total non-accrual loans	$ 949,000		$ 1,598,000

MORTGAGE SERVICING RIGHTS - Mor

MORTGAGE SERVICING RIGHTS - Mortgage Loans Serviced for Others (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Schedule of Loans Serviced for Others [Line Items]
Total mortgage loans serviced for others	$ 676,640	$ 637,508
Federal Home Loan Mortgage Corporation (Freddie Mac)
Schedule of Loans Serviced for Others [Line Items]
Total mortgage loans serviced for others	490,744	497,950
Other financial institutions
Schedule of Loans Serviced for Others [Line Items]
Total mortgage loans serviced for others	$ 185,896	$ 139,558

MORTGAGE SERVICING RIGHTS - Nar

MORTGAGE SERVICING RIGHTS - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Mar. 31, 2019
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Custodial account balances maintained in connection with serviced loans	$ 948	$ 10,100		$ 948
Discount rate used to calculate fair value of MSRs	10.00%	10.00%
Default rate used to calculate fair value of MSRs	5.00%	5.00%
Minimum
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Prepayment speed rate used to calculate fair value of MSRs	5.80%	6.00%
Maximum
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Prepayment speed rate used to calculate fair value of MSRs	82.00%	70.40%
Weighted Average
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Prepayment speed rate used to calculate fair value of MSRs		22.60%	23.30%
Single family residential
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Amount of loans sold	$ 33,400			$ 33,400
Temporary servicing period for loans sold				30 days

MORTGAGE SERVICING RIGHTS - M_2

MORTGAGE SERVICING RIGHTS - Mortgage Servicing Rights Activity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	$ 3,463	$ 4,255
Additions	155	0
Disposals	0	0
Change in fair value due to changes in assumptions	0	0
Other changes in fair value	(146)	(131)
Ending balance	$ 3,472	$ 4,124

DEPOSITS - Deposits (Details)

DEPOSITS - Deposits (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Deposits [Abstract]
Certificates of deposit	$ 3,523,187	$ 3,297,433
Money market savings	1,174,786	1,335,246
Interest bearing demand	216,580	179,272
Money market checking	127,351	123,119
Non-interest bearing demand	39,927	65,970
Deposits	$ 5,081,831	$ 5,001,040

DEPOSITS - Narrative (Details)

DEPOSITS - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Banking and Thrift [Abstract]
Certificates of deposit with a denomination of $100,000 or More	$ 2,500	$ 2,400
Certificates of deposit that meet or exceed FDIC insurance limit	1,300	1,200
Brokered deposits	$ 611.2	$ 467.5

DEPOSITS - Maturities (Details)

DEPOSITS - Maturities (Details) $ in Thousands	Mar. 31, 2019USD ($)
Maturities of Time Deposits, Twelve months ending March 31,
April 1 - December 31, 2019	$ 1,966,800
Year ending December 31, 2020	1,222,219
Year ending December 31, 2021	278,890
Year ending December 31, 2022	50,184
Year ending December 31, 2023	5,094
Time Deposits	$ 3,523,187

FEDERAL HOME LOAN BANK AND FE_3

FEDERAL HOME LOAN BANK AND FEDERAL RESERVE BANK ADVANCES - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Short-term Debt [Line Items]
Borrowing capacity based on pledged loans to the FRB and FHLB	$ 840.9	$ 681.5
Maximum short-term debt outstanding during period	209.7
Average short-term debt outstanding during period	$ 143
Weighted average interest rate	2.57%
FHLB Advances
Short-term Debt [Line Items]
Mortgage loans pledged as collateral	$ 2,300	2,100
Letters of credit pledged as collateral	62.6	62.6
FRB Advances
Short-term Debt [Line Items]
Mortgage loans pledged as collateral	423.1	$ 406.6
State of California Treasurer's Office | FHLB Advances
Short-term Debt [Line Items]
Letters of credit pledged as collateral	$ 5.5

FEDERAL HOME LOAN BANK AND FE_4

FEDERAL HOME LOAN BANK AND FEDERAL RESERVE BANK ADVANCES - FHLB Advances (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Outstanding Balances	$ 1,109,625	$ 1,143,132
FHLB of San Francisco
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Outstanding Balances	1,109,625	1,143,132
FHLB of San Francisco | Fixed rate short-term
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Outstanding Balances	$ 57,500	166,000
FHLB of San Francisco | Fixed rate short-term | Minimum
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Interest rate	2.60%
FHLB of San Francisco | Fixed rate short-term | Maximum
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Interest rate	2.60%
FHLB of San Francisco | Fixed rate short-term | Average
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Interest rate	2.60%
FHLB of San Francisco | Fixed rate long-term
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Outstanding Balances	$ 952,125	877,132
FHLB of San Francisco | Fixed rate long-term | Minimum
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Interest rate	1.05%
FHLB of San Francisco | Fixed rate long-term | Maximum
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Interest rate	7.69%
FHLB of San Francisco | Fixed rate long-term | Average
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Interest rate	2.31%
FHLB of San Francisco | Variable rate long-term
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Outstanding Balances	$ 100,000	$ 100,000
FHLB of San Francisco | Variable rate long-term | Minimum
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Interest rate	2.32%
FHLB of San Francisco | Variable rate long-term | Maximum
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Interest rate	2.98%
FHLB of San Francisco | Variable rate long-term | Average
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Interest rate	2.65%

FEDERAL HOME LOAN BANK AND FE_5

FEDERAL HOME LOAN BANK AND FEDERAL RESERVE BANK ADVANCES - Schedule of Maturities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Federal Home Loan Bank, Advances, Fiscal Year Maturity [Abstract]
Outstanding advances from FHLB	$ 1,109,625	$ 1,143,132
FHLB of San Francisco
Federal Home Loan Bank, Advances, Fiscal Year Maturity [Abstract]
April 1 - December 31, 2019	332,500
Year ending December 31, 2020	150,000
Year ending December 31, 2021	150,600
Year ending December 31, 2022	75,000
Year ending December 31, 2023	400,750
Thereafter	775
Outstanding advances from FHLB	$ 1,109,625	$ 1,143,132

JUNIOR SUBORDINATED DEFERRABL_3

JUNIOR SUBORDINATED DEFERRABLE INTEREST DEBENTURES - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)	Mar. 31, 2018trust
Investment [Line Items]
Number of wholly-owned trust companies | trust		2
Trusts
Investment [Line Items]
Investment in common securities | $	$ 1.9
Trust Preferred Securities Subject to Mandatory Redemption | Trusts
Investment [Line Items]
Interest deferment period (not exceeding)	5 years

JUNIOR SUBORDINATED DEFERRABL_4

JUNIOR SUBORDINATED DEFERRABLE INTEREST DEBENTURES - Schedule of Trusts (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Amount	$ 61,857	$ 61,857
Trust Preferred Securities Subject to Mandatory Redemption | Luther Burbank Statutory Trust I | Trusts
Debt Instrument [Line Items]
Amount	$ 41,238	$ 41,238
Rate	3.99%	4.17%
Trust Preferred Securities Subject to Mandatory Redemption | Luther Burbank Statutory Trust I | Trusts | LIBOR
Debt Instrument [Line Items]
Rate Index (Quarterly Reset)	1.38%
Trust Preferred Securities Subject to Mandatory Redemption | Luther Burbank Statutory Trust II | Trusts
Debt Instrument [Line Items]
Amount	$ 20,619	$ 20,619
Rate	4.23%	4.41%
Trust Preferred Securities Subject to Mandatory Redemption | Luther Burbank Statutory Trust II | Trusts | LIBOR
Debt Instrument [Line Items]
Rate Index (Quarterly Reset)	1.62%

SENIOR DEBT - Narrative (Detail

SENIOR DEBT - Narrative (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2014
Senior Unsecured Term Notes, September 2014 | Senior Unsecured Term Notes
Debt Instrument [Line Items]
Principal	$ 95,000,000	$ 95,000,000	$ 95,000,000

SENIOR DEBT - Schedule of Debt

SENIOR DEBT - Schedule of Debt (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2014
Debt Instrument [Line Items]
Fixed Interest Rate	6.50%
Senior Unsecured Term Notes, September 2014 | Senior Unsecured Term Notes
Debt Instrument [Line Items]
Principal	$ 95,000,000	$ 95,000,000	$ 95,000,000
Unamortized Debt Issuance Costs	$ 676,000	$ 707,000
Fixed Interest Rate	6.50%

STOCK BASED COMPENSATION - Narr

STOCK BASED COMPENSATION - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Mar. 31, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for new awards (in shares)			3,360,000
Common stock available for grant (in shares)	2,287,025	2,581,960		2,287,025
RSUs and RSAs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			3 years
Stock-based compensation expense				$ 838	$ 1,000
Fair value of awards vested				5,700	$ 1,500
Unrecognized compensation expense	$ 6,300	$ 4,300		$ 6,300
Restricted stock awards or units granted (in shares)	758,182	985,869		758,182
Period of recognition for unrecognized compensation expense	2 years 1 month 15 days	1 year 10 months 28 days
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units vested (in shares)	522,464	169,490		522,464
Non-employee directors | Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			1 year
Minimum | Employees | Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			3 years
Maximum | Employees | Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			4 years

STOCK BASED COMPENSATION - Awar

STOCK BASED COMPENSATION - Awards Activity (Details) - RSUs and RSAs - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Number of Shares
Beginning of the period balance (in shares)	1,155,359	1,319,700
Shares granted (in shares)	297,663	131,140
Shares settled (in shares)	(169,648)	(53,059)
Shares forfeited (in shares)	(2,728)	(1,400)
End of the period balance (in shares)	1,280,646	1,396,381
Weighted Average Grant Date Fair Value
Beginning of the period balance (in usd per share)	$ 10.97	$ 10.75
Shares granted (in usd per share)	9.79	12.77
Shares settled (in usd per share)	11.43	10.75
Shares forfeited (in usd per share)	10.75	10.75
End of the period balance (in usd per share)	$ 10.63	$ 10.94

FAIR VALUE MEASUREMENTS - Fair

FAIR VALUE MEASUREMENTS - Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Debt securities:
Available for sale debt securities, at fair value	$ 638,795	$ 608,528
Held to maturity	11,376	11,625
Equity securities	11,582	11,438
Carrying Amount
Financial assets:
Cash and cash equivalents	104,575	91,697
Debt securities:
Available for sale debt securities, at fair value	638,795	608,528
Held to maturity	11,450	11,860
Equity securities	11,582	11,438
Loans receivable, net	6,109,576	6,096,316
Accrued interest receivable	21,292	20,220
FHLB stock	32,047	31,823
Financial liabilities:
Deposits	5,081,831	5,001,040
FHLB advances	1,109,625	1,143,132
Junior subordinated deferrable interest debentures	61,857	61,857
Senior debt	94,324	94,293
Accrued interest payable	5,476	4,307
Fair Value
Financial assets:
Cash and cash equivalents	104,575	91,697
Debt securities:
Available for sale debt securities, at fair value	638,795	608,528
Held to maturity	11,376	11,625
Equity securities	11,582	11,438
Loans receivable, net	6,130,635	6,092,885
Accrued interest receivable	21,292	20,220
Financial liabilities:
Deposits	5,086,375	4,957,054
FHLB advances	1,118,110	1,144,326
Junior subordinated deferrable interest debentures	57,481	56,596
Senior debt	99,268	99,673
Accrued interest payable	5,476	4,307
Fair Value | Level 1
Financial assets:
Cash and cash equivalents	104,575	91,697
Debt securities:
Available for sale debt securities, at fair value	986	976
Held to maturity	0	0
Equity securities	0	0
Loans receivable, net	0	0
Accrued interest receivable	24	62
Financial liabilities:
Deposits	1,558,644	1,703,607
FHLB advances	0	0
Junior subordinated deferrable interest debentures	0	0
Senior debt	0	0
Accrued interest payable	0	0
Fair Value | Level 2
Financial assets:
Cash and cash equivalents	0	0
Debt securities:
Available for sale debt securities, at fair value	637,809	607,552
Held to maturity	11,376	11,625
Equity securities	11,582	11,438
Loans receivable, net	0	0
Accrued interest receivable	1,797	1,739
Financial liabilities:
Deposits	3,527,731	3,253,447
FHLB advances	1,118,110	1,144,326
Junior subordinated deferrable interest debentures	57,481	56,596
Senior debt	99,268	99,673
Accrued interest payable	5,476	4,307
Fair Value | Level 3
Financial assets:
Cash and cash equivalents	0	0
Debt securities:
Available for sale debt securities, at fair value	0	0
Held to maturity	0	0
Equity securities	0	0
Loans receivable, net	6,130,635	6,092,885
Accrued interest receivable	19,471	18,419
Financial liabilities:
Deposits	0	0
FHLB advances	0	0
Junior subordinated deferrable interest debentures	0	0
Senior debt	0	0
Accrued interest payable	$ 0	$ 0

FAIR VALUE MEASUREMENTS - Asset

FAIR VALUE MEASUREMENTS - Assets and Liabilities Recorded at Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	$ 638,795	$ 608,528
Equity securities	11,582	11,438
Mortgage servicing rights	3,472	3,463	$ 4,124	$ 4,255
Residential mortgage backed securities and collateralized mortgage obligations (MBS and CMOs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	179,804	192,113
Commercial MBS and CMOs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	324,774	292,951
Agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	133,231	122,488
U.S. Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	986	976
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	638,795	608,528
Equity securities	11,582	11,438
Fair Value | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	986	976
Equity securities	0	0
Fair Value | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	637,809	607,552
Equity securities	11,582	11,438
Fair Value | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	0	0
Equity securities	0	0
Fair Value | Recurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	638,795	608,528
Equity securities	11,582	11,438
Mortgage servicing rights	3,472	3,463
Fair Value | Recurring Basis | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	986	976
Equity securities	0	0
Mortgage servicing rights	0	0
Fair Value | Recurring Basis | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	637,809	607,552
Equity securities	11,582	11,438
Mortgage servicing rights	0	0
Fair Value | Recurring Basis | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	0	0
Equity securities	0	0
Mortgage servicing rights	3,472	3,463
Fair Value | Recurring Basis | Residential mortgage backed securities and collateralized mortgage obligations (MBS and CMOs)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	179,804	192,113
Fair Value | Recurring Basis | Residential mortgage backed securities and collateralized mortgage obligations (MBS and CMOs) | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	0	0
Fair Value | Recurring Basis | Residential mortgage backed securities and collateralized mortgage obligations (MBS and CMOs) | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	179,804	192,113
Fair Value | Recurring Basis | Residential mortgage backed securities and collateralized mortgage obligations (MBS and CMOs) | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	0	0
Fair Value | Recurring Basis | Commercial MBS and CMOs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	324,774	292,951
Fair Value | Recurring Basis | Commercial MBS and CMOs | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	0	0
Fair Value | Recurring Basis | Commercial MBS and CMOs | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	324,774	292,951
Fair Value | Recurring Basis | Commercial MBS and CMOs | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	0	0
Fair Value | Recurring Basis | Agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	133,231	122,488
Fair Value | Recurring Basis | Agency bonds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	0	0
Fair Value | Recurring Basis | Agency bonds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	133,231	122,488
Fair Value | Recurring Basis | Agency bonds | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	0	0
Fair Value | Recurring Basis | U.S. Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	986	976
Fair Value | Recurring Basis | U.S. Treasury | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	986	976
Fair Value | Recurring Basis | U.S. Treasury | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	0	0
Fair Value | Recurring Basis | U.S. Treasury | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities, at fair value	$ 0	$ 0

FAIR VALUE MEASUREMENTS - Narra

FAIR VALUE MEASUREMENTS - Narrative (Details)	Dec. 31, 2018USD ($)
Nonrecurring Basis
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value, net asset (liability)	$ 0

VARIABLE INTEREST ENTITIES (V_2

VARIABLE INTEREST ENTITIES (VIE) (Details) - Variable Interest Entity, Not Primary Beneficiary - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Variable Interest Entity [Line Items]
Maximum loss exposure as a percentage of original principal amount	10.00%
Maximum loss exposure	$ 62.6
Reserved for estimated losses	$ 1.4	$ 1.4

LOAN SALE AND SECURITIZATION _3

LOAN SALE AND SECURITIZATION ACTIVITIES - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Line Items]
Minimum net worth	$ 2
Actual net worth	$ 723.6
Multifamily Loan Securitization
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Line Items]
Maximum loss exposure as a percentage of original principal amount	10.00%
Single family residential
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Line Items]
Amount of loans sold	$ 33.4
Temporary servicing period for loans sold	30 days
Loans receivable | Multifamily residential | Permanent mortgages
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Line Items]
Amount of loans sold	$ 626

LOAN SALE AND SECURITIZATION _4

LOAN SALE AND SECURITIZATION ACTIVITIES - Cash Flow from Sale of Loans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Transfers and Servicing [Abstract]
Proceeds from loan sales	$ 53,772	$ 24,691
Servicing fees	$ 332	$ 108

LOAN SALE AND SECURITIZATION _5

LOAN SALE AND SECURITIZATION ACTIVITIES - Loans Transfered Through Loans or Securitization (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Single family residential
Derecognized Assets, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together [Line Items]
Principal balance of loans	$ 59,347	$ 26,200
Loans 90 days past due	0	0
Charge-offs, net	0	0
Multifamily residential
Derecognized Assets, Securitized or Asset-backed Financing Arrangement Assets and any Other Financial Assets Managed Together [Line Items]
Principal balance of loans	617,293	611,308
Loans 90 days past due	0	0
Charge-offs, net	$ 0	$ 0

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Operating Leased Assets [Line Items]
Rent expense for operating leases	$ 1,300	$ 1,300
Sublease income	177	$ 201
Cash balances held at other institutions that exceed FDIC insured limits	$ 1,100		$ 736
Operating Lease Arrangement Type One
Operating Leased Assets [Line Items]
Renewal term	3 years
Operating Lease Arrangement Type Two
Operating Leased Assets [Line Items]
Renewal term	5 years
Operating Lease Arrangement Type Three
Operating Leased Assets [Line Items]
Renewal term	10 years
Commitments to Extend Credit
Operating Leased Assets [Line Items]
Real estate loan funding commitments	$ 89,200		70,900
Unfunded Loan Commitment
Operating Leased Assets [Line Items]
Reserve recorded on real estate loan funding commitments	$ 24		$ 52

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES - Operating Lease Maturities (Details) $ in Thousands	Mar. 31, 2019USD ($)
Operating Lease Liabilities, Payments Due [Abstract]
April 1 - December 31, 2019	$ 3,965
Year ending December 31, 2020	3,952
Year ending December 31, 2021	3,484
Year ending December 31, 2022	2,526
Year ending December 31, 2023	1,257
Thereafter	1,289
Total	$ 16,473