Columbia Financial (CLBK) 10-K 1 Mar 21 2020 FY Annual report Financial data

Cover Page

Cover Page - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Feb. 19, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-38456
Entity Registrant Name	COLUMBIA FINANCIAL, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	22-3504946
Entity Address, Address Line One	19-01 Route 208 North,
Entity Address, City or Town	Fair Lawn,
Entity Address, State or Province	NJ
Entity Address, Postal Zip Code	07410
City Area Code	800
Local Phone Number	522-4167
Title of 12(b) Security	Common stock, par value $0.01 per share
Trading Symbol	CLBK
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Filer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 582.8
Entity Common Stock, Shares Outstanding (in shares)		109,673,314
Documents Incorporated by Reference	Portions of the Registrant’s Proxy Statement for the 2021 Annual Meeting of Stockholders are incorporated by reference into Part III of this Form 10-K.
Entity Central Index Key	0001723596
Document Fiscal Year Focus	2020
Document Fiscal Period	FY
Amendment Flag	false

Consolidated Statements of Fina

Consolidated Statements of Financial Condition - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Assets
Cash and due from banks	$ 422,787	$ 75,420
Short-term investments	170	127
Total cash and cash equivalents	422,957	75,547
Debt securities available for sale, at fair value	1,316,952	1,098,336
Debt securities held to maturity, at amortized cost (fair value of $277,091 and $289,505 at December 31, 2020 and 2019, respectively)	262,720	285,756
Equity securities, at fair value	5,418	2,855
Federal Home Loan Bank stock	43,759	69,579
Loans held-for-sale, at fair value	4,146	0
Loans receivable	6,181,770	6,197,566
Less: allowance for credit losses	74,676	61,709
Loans receivable, net	6,107,094	6,135,857
Accrued interest receivable	29,456	22,092
Office properties and equipment, net	75,974	72,967
Bank-owned life insurance	232,824	211,415
Goodwill and intangible assets	87,384	68,582
Other assets	209,852	145,708
Total assets	8,798,536	8,188,694
Liabilities:
Deposits	6,778,624	5,645,842
Borrowings	799,364	1,407,022
Advance payments by borrowers for taxes and insurance	32,570	35,507
Accrued expenses and other liabilities	176,691	117,806
Total liabilities	7,787,249	7,206,177
Stockholders' equity:
Preferred stock, $0.01 par value. 10,000,000 shares authorized; none issued and outstanding at December 31, 2020 and 2019	0	0
Common stock, $0.01 par value. 500,000,000 shares authorized; 122,037,793 shares issued and 110,939,753 shares outstanding at December 31, 2020, and 117,278,745 shares issued and 113,765,387 shares outstanding at December 31, 2019	1,220	1,173
Additional paid-in capital	609,531	531,667
Retained earnings	673,084	615,481
Accumulated other comprehensive loss	(69,625)	(68,735)
Treasury stock, at cost; 11,098,040 shares at December 31, 2020 and 3,513,358 shares at December 31, 2019	(163,015)	(54,950)
Common stock held by the Employee Stock Ownership Plan	(39,293)	(41,564)
Stock held by Rabbi Trust	(1,875)	(1,520)
Deferred compensation obligations	1,260	965
Total stockholders' equity	1,011,287	982,517
Total liabilities and stockholders' equity	$ 8,798,536	$ 8,188,694

Consolidated Statements of Fi_2

Consolidated Statements of Financial Condition (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Assets
Debt securities held to maturity	$ 277,091	$ 289,505
Stockholders' equity:
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	122,037,793	117,278,745
Common stock, shares outstanding (in shares)	110,939,753	113,765,387
Treasury stock, shares (in shares)	11,098,040	3,513,358

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest income:
Loans receivable	$ 255,236	$ 217,774	$ 189,869
Debt securities available for sale and equity securities	28,376	30,938	25,338
Debt securities held to maturity	8,025	8,180	7,147
Federal funds and interest-earning deposits	413	594	1,175
Federal Home Loan Bank stock dividends	3,661	3,597	2,761
Total interest income	295,711	261,083	226,290
Interest expense:
Deposits	55,246	61,551	39,523
Borrowings	18,892	27,161	22,733
Total interest expense	74,138	88,712	62,256
Net interest income	221,573	172,371	164,034
Provision for loan losses	18,447	4,224	6,677
Net interest income after provision for credit losses	203,126	168,147	157,357
Non-interest income:
Bank-owned life insurance	6,620	5,846	5,208
Gain on securities transactions	370	2,612	116
Change in fair value of equity securities	767	305	0
Gain on sale of loans	5,444	785	618
Other non-interest income	6,983	5,922	4,943
Total non-interest income	31,270	31,636	21,688
Non-interest expense:
Compensation and employee benefits	100,687	84,256	77,226
Occupancy	19,170	16,180	14,547
Federal deposit insurance premiums	1,901	895	1,893
Advertising	2,641	3,932	4,137
Professional fees	5,810	5,913	4,619
Data processing	3,342	3,001	2,600
Charitable contribution to foundation	0	0	34,767
Merger-related expenses	1,931	2,755	0
Loss on extinguishment of debt	1,158	0	0
Other non-interest expense	21,499	11,769	5,597
Total non-interest expense	158,139	128,701	145,386
Income before income tax expense	76,257	71,082	33,659
Income tax expense	18,654	16,365	10,923
Net income	$ 57,603	$ 54,717	$ 22,736
Earnings per share - basic and diluted (in dollars per share)	$ 0.52	$ 0.49	$ 0.20
Weighted average shares outstanding - basic and diluted (in shares)	109,755,924	111,101,246	111,395,723
Demand deposit account fees
Non-interest income:
Revenue	$ 3,633	$ 4,478	$ 3,987
Title insurance fees
Non-interest income:
Revenue	5,034	4,981	4,297
Loan fees and service charges
Non-interest income:
Revenue	$ 2,419	$ 6,707	$ 2,519

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 57,603	$ 54,717	$ 22,736
Other comprehensive income (loss), net of tax:
Unrealized gain (loss) on debt securities available for sale	21,236	21,067	(5,778)
Accretion of unrealized gain (loss) on debt securities reclassified as held to maturity	126	9	(13)
Reclassification adjustment for gain (loss) included in net income	289	2,011	(92)
Total other comprehensive (loss) income, available-for-sale securities and held-to-maturity adjustments, net of tax	21,651	23,087	(5,883)
Derivatives, net of tax:
Unrealized (loss) on swap contracts accounted for as cash flow hedges	(8,382)	(6,468)	(2,230)
Total derivative, net of tax	(8,382)	(6,468)	(2,230)
Employee benefit plans, net of tax:
Amortization of prior service cost included in net income	(44)	(44)	(491)
Reclassification adjustment of actuarial net (loss) gain included in net income	(3,384)	(2,930)	1,996
Change in funded status of retirement obligations	(10,731)	(9,935)	121
Total employee benefit plans, net of tax	(14,159)	(12,909)	1,626
Total other comprehensive (loss) income	(890)	3,710	(6,487)
Total comprehensive income, net of tax	$ 56,713	$ 58,427	$ 16,249

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	IPO	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjusted Balance	Common Stock	Common StockIPO	Common StockCumulative Effect, Period of Adoption, Adjusted Balance	Additional Paid-in-Capital	Additional Paid-in-CapitalIPO	Additional Paid-in-CapitalCumulative Effect, Period of Adoption, Adjusted Balance	Retained Earnings	Retained EarningsCumulative Effect, Period of Adoption, Adjustment	Retained EarningsCumulative Effect, Period of Adoption, Adjusted Balance	Accumulated Other Comprehensive (Loss)	Accumulated Other Comprehensive (Loss)Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive (Loss)Cumulative Effect, Period of Adoption, Adjusted Balance	Treasury Stock	Treasury StockCumulative Effect, Period of Adoption, Adjusted Balance	Common Stock Held by the Employee Stock Ownership Plan	Common Stock Held by the Employee Stock Ownership PlanCumulative Effect, Period of Adoption, Adjusted Balance	Stock Held by Rabbi Trust	Stock Held by Rabbi TrustCumulative Effect, Period of Adoption, Adjusted Balance	Deferred Compensation Obligations	Deferred Compensation ObligationsCumulative Effect, Period of Adoption, Adjusted Balance	Columbia Bank, MHC	Columbia Bank, MHCCommon Stock	Columbia Bank Foundation	Columbia Bank FoundationCommon Stock	Columbia Bank FoundationAdditional Paid-in-Capital
Balance at beginning of period at Dec. 31, 2017	$ 472,070				$ 0			$ 0			$ 537,480			$ (65,410)			$ 0		$ 0		$ 0		$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	22,736										22,736
Other comprehensive income (loss)	(6,487)													(6,487)
Issuance of common stock		$ 491,802				$ 498			$ 491,304																$ 626	$ 626	$ 34,767	$ 35	$ 34,732
Repurchase shares for taxes	(45,428)							0											(45,428)
Employee Stock Ownership Plan shares committed to be released	2,594							1,001											1,593
Funding of deferred compensation obligations	(620)																				(1,259)		639
Balance at end of year at Dec. 31, 2018	$ 972,060		$ 0	$ 972,060	1,159		$ 1,159	527,037		$ 527,037	560,216	$ 548	$ 560,764	(71,897)	$ (548)	$ (72,445)	0	$ 0	(43,835)	$ (43,835)	(1,259)	$ (1,259)	639	$ 639
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201601Member
Issuance of common stock (in shares)						49,832,345																				62,580,155		3,476,675
Net income	$ 54,717										54,717
Other comprehensive income (loss)	3,710													3,710
Issuance of common stock	14				14
Treasury stock allocated to restricted stock award grants	0							(1,095)									1,095
Stock based compensation	3,694							3,694
Purchase of treasury stock shares	(55,309)																(55,309)
Restricted stock forfeitures	0							736									(736)
Employee Stock Ownership Plan shares committed to be released	3,566							1,295											2,271
Funding of deferred compensation obligations	65																				(261)		326
Balance at end of year at Dec. 31, 2019	$ 982,517				1,173			531,667			615,481			(68,735)		$ (68,735)	(54,950)		(41,564)		(1,520)		965
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)	1,464,243
Net income	$ 57,603										57,603
Other comprehensive income (loss)	(890)													(890)
Issuance of common stock	68,530				47			68,483
Treasury stock allocated to restricted stock award grants	0							(481)									481
Stock based compensation	8,790							8,790
Purchase of treasury stock shares	(108,166)																(108,166)
Restricted stock forfeitures	(24)							175									(199)
Repurchase shares for taxes	(174)							7									(181)
Employee Stock Ownership Plan shares committed to be released	3,161							890											2,271
Funding of deferred compensation obligations	(60)																				(355)		295
Balance at end of year at Dec. 31, 2020	$ 1,011,287				$ 1,220			$ 609,531			$ 673,084			$ (69,625)			$ (163,015)		$ (39,293)		$ (1,875)		$ 1,260
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)	4,759,048

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2018
Issuance of common stock (in shares)	4,759,048
Treasury stock, shares purchased (in shares)	7,587,142
Restricted stock, shares forfeited (in shares)	17,247	44,231
Repurchased shares for taxes (in shares)	13,453
Common Stock | IPO
Issuance of common stock (in shares)		49,832,345
Columbia Bank, MHC | Common Stock
Issuance of common stock (in shares)		62,580,155
Columbia Bank Foundation | Common Stock
Issuance of common stock (in shares)		3,476,675

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net income	$ 57,603,000	$ 54,717,000	$ 22,736,000
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of deferred loan fees, costs, and purchased premiums and discounts	(1,464,000)	1,205,000	1,965,000
Net amortization of premiums and discounts on securities	2,508,000	1,160,000	1,212,000
Net amortization of mortgage servicing rights	130,000	(109,000)	(88,000)
Amortization of debt issuance costs	0	0	890,000
Amortization of intangible assets	1,048,000	222,000	0
Depreciation and amortization of office properties and equipment	6,543,000	4,880,000	3,839,000
Amortization of operating lease right-of-use assets	2,641,000	0	0
Provision for loan losses	18,447,000	4,224,000	6,677,000
Gain on securities transactions	(370,000)	(2,612,000)	(116,000)
Change in fair value of equity securities	(767,000)	(305,000)	0
Gain on securitizations	(3,544,000)	0	0
Gain on sale of loans	(1,900,000)	(785,000)	(618,000)
Loss on real estate owned	0	1,000	56,000
Loss on write-down of real estate owned	0	0	55,000
Loss (gain) on disposal of office properties and equipment	734,000	3,000	(5,000)
Loss on write-down of office properties and equipment	114,000	0	0
Loss on write-down of mortgage servicing rights	75,000	0	0
Deferred tax expense (benefit)	9,738,000	7,527,000	(5,490,000)
(Increase) in accrued interest receivable	(6,685,000)	(959,000)	(2,979,000)
(Increase) in other assets	(75,127,000)	(51,856,000)	(11,053,000)
Increase in accrued expenses and other liabilities	32,891,000	3,032,000	7,980,000
Income on bank-owned life insurance	(6,620,000)	(5,846,000)	(5,208,000)
Contribution of common stock to Columbia Bank Foundation	0	0	34,767,000
Employee stock ownership plan expense	3,161,000	3,566,000	2,594,000
Stock based compensation	8,790,000	3,694,000	0
(Increase) decrease in deferred compensation obligations under Rabbi Trust	(60,000)	65,000	(620,000)
Net cash provided by operating activities	47,886,000	21,824,000	56,594,000
Cash flows from investing activities:
Proceeds from sales of debt securities available for sale	20,761,000	65,198,000	11,513,000
Proceeds from sales of equity securities	0	1,065,000	0
Proceeds from paydown/maturities/calls of debt securities available for sale	247,908,000	149,683,000	69,977,000
Proceeds from paydown/maturities/calls of debt securities held to maturity	48,640,000	46,133,000	8,820,000
Purchases of debt securities available for sale	(292,809,000)	(176,171,000)	(413,804,000)
Purchases of debt securities held to maturity	(12,815,000)	(70,126,000)	(31,639,000)
Purchases of equity securities	0	(416,000)	0
Proceeds from sales of loans held-for-sale	111,764,000	101,946,000	3,615,000
Proceeds from sales of loans receivable	35,613,000	11,671,000	32,039,000
Purchases of loans receivable	0	(89,774,000)	(32,251,000)
Net increase in loans receivable	(80,498,000)	(503,772,000)	(536,129,000)
Purchase of bank-owned life insurance	0	0	(30,000,000)
Proceeds from bank-owned life insurance death benefits	627,000	1,015,000	1,241,000
Proceeds from redemptions of Federal Home Loan Bank stock	50,374,000	72,871,000	67,035,000
Purchases of Federal Home Loan Bank stock	(22,544,000)	(79,796,000)	(81,309,000)
Proceeds from sales of office properties and equipment	0	0	8,000
Additions to office properties and equipment	(4,624,000)	(19,344,000)	(13,272,000)
Proceeds from sales of real estate owned	0	91,000	1,007,000
Net cash acquired in acquisitions	155,248,000	(31,288,000)	0
Net cash provided by (used in) investing activities	257,645,000	(521,014,000)	(943,149,000)
Cash flows from financing activities:
Net increase in deposits	799,548,000	449,270,000	150,558,000
Proceeds from long-term borrowings	90,000,000	140,000,000	220,980,000
Payments on long-term borrowings	(343,939,000)	(230,000,000)	(210,000,000)
Net (decrease) increase in short-term borrowings	(374,847,000)	225,081,000	299,800,000
Payments of subordinated debt and trust preferred securities	(16,600,000)	0	(51,547,000)
(Decrease) increase in advance payments by borrowers for taxes and insurance	(3,919,000)	3,121,000	6,467,000
Issuance of common stock	0	14,000	492,428,000
Purchase of treasury stock	(108,166,000)	(55,309,000)	0
Purchase of employee stock ownership plan shares	0	0	(45,428,000)
Restricted stock forfeitures	(24,000)	(736,000)	0
Restricted stock repurchased on vesting to pay taxes	(174,000)	0	0
Issuance of treasury stock allocated to restricted stock award grants	0	1,095,000	0
Net cash provided by financing activities	41,879,000	532,536,000	863,258,000
Net increase (decrease) in cash and cash equivalents	347,410,000	33,346,000	(23,297,000)
Cash and cash equivalents at beginning of period	75,547,000	42,201,000	65,498,000
Cash and cash equivalents at end of period	422,957,000	75,547,000	42,201,000
Cash paid during the period for:
Interest on deposits and borrowings	75,557,000	87,370,000	61,987,000
Income tax payments, net of (refunds)	10,526,000	(2,893,000)	21,325,000
Non-cash investing and financing activities:
Transfer of loans receivable to real estate owned	0	0	251,000
Transfer of loans receivable to loans held-for-sale	114,171,000	93,147,000	11,696,000
Securitization of loans	117,259,000	21,615,000	0
Initial recognition of operating lease right-of-use asset	22,218,000	0	0
Initial recognition of operating lease liabilities	23,290,000	0	0
Non-cash assets acquired:
Debt securities available for sale	51,479,000	51,710,000	0
Debt securities held to maturity	13,418,000	0	0
Equity securities	1,796,000	1,073,000	0
Federal Home Loan Bank stock	2,010,000	3,716,000	0
Loans receivable	171,593,000	757,223,000	0
Accrued interest receivable	679,000	2,239,000	0
Office properties and equipment, net	5,774,000	6,815,000	0
Bank-owned life insurance	17,245,000	22,096,000	0
Deferred tax assets, net	6,475,000	3,534,000	0
Core deposit and other intangibles	0	7,467,000	0
Other assets	1,489,000	767,000	0
Total non-cash assets acquired	271,958,000	856,640,000	0
Liabilities assumed:
Deposits	333,234,000	782,698,000	0
Borrowings	37,728,000	82,761,000	0
Advance payments by borrowers for taxes and insurance	982,000	356,000	0
Accrued expenses and other liabilities	5,400,000	14,584,000	0
Total liabilities assumed	377,344,000	880,399,000	0
Net non-cash liabilities acquired	(105,386,000)	(23,759,000)	0
Net cash and cash equivalents acquired in acquisition	$ 155,248,000	$ 105,006,000	$ 0

Business

Business	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business	Business On April 19, 2018, the Company completed its minority stock offering, after receiving all regulatory approvals. In connection with the closing, 62,580,155 shares of its common stock were issued to Columbia Bank, MHC (the "MHC"), the mutual holding company of Columbia Financial, Inc., 3,476,675 shares were issued to the Columbia Bank Foundation, the Bank's charitable foundation, and 49,832,345 shares were issued to depositors of the Bank, who subscribed for and were allocated shares in the minority stock offering, as well as the Columbia Bank Employee Stock Ownership Plan (the "ESOP"). The accounts of the MHC are not consolidated in the consolidated financial statements of the Company. On November 1, 2019, the Company completed its acquisition of Stewardship Financial Corporation ("Stewardship"), pursuant to the Agreement and Plan of Merger, dated as of June 6, 2019 (the "Merger Agreement"), by and among Columbia Financial, Broadway Acquisition Corp. (a wholly owned subsidiary of Columbia Financial) and Stewardship. Under the terms of the merger agreement, each outstanding share of Stewardship common stock was converted into the right to received $15.75 in cash at the effective time of the merger.The total consideration paid was $136.3 million. On April 1, 2020, the Company completed its acquisition of RSB Bancorp, MHC, RSB Bancorp, Inc. and Roselle Bank (collectively, the "Roselle Entities" or "Roselle"). Pursuant to the terms of the Merger Agreement, RSB Bancorp, MHC merged with and into the MHC, with the MHC as the surviving entity; and Roselle Bank merged with and into the Bank, with the Bank as the surviving institution. Under the terms of the merger agreement, depositors of Roselle Bank became depositors of the Bank and have the same rights and privileges in the MHC as if their accounts had been established at the Bank on the date established at Roselle Bank. The Company issued 4,759,048 shares of its common stock to the MHC, representing an amount equal to the fair value of the Roselle Entities as determined by an independent appraiser, at the effective time of the merger.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Principles of Consolidation The accompanying consolidated financial statements include the accounts of Columbia Financial, Inc., its wholly-owned subsidiary, Columbia Bank (the "Bank") and the Bank's wholly-owned subsidiaries, Columbia Investment Services, Inc., 2500 Broadway Corp. 1901 Residential Management Co. LLC, Plaza Financial Services, Inc., First Jersey Title Services, Inc., Real Estate Management Corp. LLC, 1901 Commercial Management Co. LLC, Stewardship Realty LLC, and CSB Realty Corp. (collectively, the “Company”). In consolidation, all intercompany accounts and transactions are eliminated. Certain reclassifications have been made in the consolidated financial statements to conform with current year classifications. During the year ended December 31, 2020, the Company revised the Consolidated Statements of Cash Flows for the years ended December 31, 2019 and 2018. The revision consisted of reclassifying the proceeds from sales of loans held-for-sale from cash flows from operating activities to cash flows from investing activities. The impact of these revisions was a decrease to cash flows from operating activities and an increase to cash flows from investing activities of $101.9 million and $3.6 million for the years ended December 31, 2019 and 2018, respectively. The revisions had no impact on cash and cash equivalents as of December 31, 2019 and 2018. The Company also owned 100% of the common stock of Columbia Financial Capital Trust I (the "Trust"). The Trust was used to issue trust preferred securities. In accordance with Accounting Standards Codification ("ASC") Topic 810, Consolidation , the Trust was classified as a variable interest entity and did not satisfy the conditions for consolidation. Accordingly, the Trust was treated as an unconsolidated subsidiary. In August 2018, the Company redeemed, in full $51.5 million of junior subordinated debt securities, which represented 100% of the assets of the Trust. The Bank's wholly owned subsidiary, Stewardship Realty, LLC, incorporated as a New Jersey corporation in 2005 was acquired in the Company's merger with Stewardship in November 2019. It is a service corporation originally organized to hold and manage property in Midland Park which was previously occupied by Atlantic Stewardship Bank. The Company also owns 100% of the common stock of Stewardship Statutory Trust I, which is a trust incorporated in Delaware which was also acquired in the Company's merger with Stewardship in November 2019. In accordance with ASC Topic 810, Consolidation , this Trust was classified as a variable interest entity and did not satisfy the conditions for consolidation. Accordingly, this Trust, which owns $7.0 million of trust preferred securities, which represents 100% of the assets, is treated as an unconsolidated subsidiary. (2) Summary of Significant Accounting Policies (continued) Basis of Financial Statement Presentation The consolidated financial statements of the Company have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). In preparing the consolidated financial statements, management is required to make estimates and assumptions about future events. These estimates and the underlying assumptions affect the reported amounts of assets and liabilities and disclosures about contingent assets and liabilities as of the dates of the Consolidated Statements of Financial Condition, and Consolidated Statements of Income for the periods presented. Material estimates that are particularly susceptible to change are the determination of the adequacy of the allowance for credit losses, evaluation of goodwill for impairment, evaluation of other-than-temporary impairment on securities, evaluation of the need for valuation allowances on deferred tax assets, and determination of liabilities related to retirement and other post-retirement benefits, among others. These estimates and assumptions are based on management’s best estimates and judgment. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment, which management believes to be reasonable under the circumstances. Such estimates and assumptions are adjusted when facts and circumstances dictate. Illiquid credit markets, volatile securities markets, and declines in the housing market and the economy generally have combined to increase the uncertainty inherent in such estimates and assumptions. As future events and their effects cannot be determined with precision, actual results could differ significantly from these estimates. Changes in estimates resulting from continuing changes in the economic environment will be reflected in the consolidated financial statements in future periods. Cash and Cash Equivalents Cash and cash equivalents include cash on hand, amounts due from banks and interest-bearing deposits at other financial institutions and short-term investments. The Company is required by the Federal Reserve Bank System to maintain cash reserves equal to a percentage of certain deposits. At December 31, 2020 and 2019, the reserve requirement totaled $4.9 million and $8.8 million, respectively. Securities Securities are classified as available for sale and held to maturity. Management determines the appropriate classification of securities at the time of purchase. Securities that management has the positive intent and ability to hold to maturity are classified as held to maturity and reported at amortized cost. Securities not classified as held to maturity are classified as available for sale and carried at estimated fair value, with unrealized holding gains or losses, net of taxes, reported as a separate component of accumulated other comprehensive income or loss ("OCI") included in stockholders' equity. The fair values of these securities are based on market quotations or matrix pricing as discussed in note 17. The Company evaluates securities for other-than-temporary impairment at each reporting period and more frequently when economic or market conditions warrant such evaluation. In this evaluation, if such declines were deemed other-than temporary, management would measure the total credit-related component of the unrealized loss, and recognize that portion of the loss as a charge to current period earnings. The remaining portion of the unrealized loss would be recognized as an adjustment to OCI. The fair value of the securities portfolio is significantly affected by changes in interest rates. In general, as interest rates rise, the fair value of fixed-rate securities decreases and as interest rates fall, the fair value of fixed-rate securities increases. The Company determines if it has the intent to sell securities or if it more likely than not that the Company would be required to sell the securities before the anticipated recovery. If either exists, the decline in value is considered other-than-temporary and would be recognized in current period earnings. Premiums and discounts on securities are generally amortized and accreted to income over the contractual lives of the securities using the level-yield method. Premiums on callable securities are amortized to the earliest call date. Dividend and interest income are recognized when earned. Realized gains and losses are recognized when securities are sold or called based on the specific identification method. In the ordinary course of business, securities are pledged as collateral in conjunction with the Company’s borrowings, lines of credit, and public funds on deposit. Federal Home Loan Bank Stock The Bank, as a member of the Federal Home Loan Bank of New York (the "FHLB"), is required to hold shares of capital stock of the FHLB based on its activities, primarily its outstanding borrowings. The Bank carries the investment at cost, or par value, which approximates fair value. Cash dividends are reported as income. (2) Summary of Significant Accounting Policies (continued) Loans Held-for-Sale Loans held-for-sale consists of loans intended for sale in the secondary market. These loans are carried at the lower of cost or estimated fair value, less costs to sell, as determined on an individual loan basis. Net unrealized losses, if any, are recognized in a valuation allowance through a charge to earnings. Origination fees and costs on loans held-for-sale are deferred and recognized on settlement dates as a component of the gain or loss on sale. Loans held-for-sale are generally sold with loan servicing rights retained by the Bank. Loans Receivable Loans receivable are carried at unpaid principal balances adjusted by unamortized premiums and unearned discounts, net deferred origination fees and costs less the allowance for loan losses. The Bank defers loan origination fees and certain direct loan origination costs and accretes such amounts as an adjustment to the yield over the expected lives of the related loans using the level-yield method. Interest income on loans is accrued and credited to income as earned. Premiums and discounts on loans purchased are amortized or accreted as an adjustment to yield over the contractual lives of the related loans using methodologies which approximate the level-yield method. A loan is considered delinquent when payment has not been received within 30 days of its contractual due date. Generally, a loan in designated as a non-accrual loan when the payment of interest is 90 days or more in arrears of its contractual due date. When a loan is placed on non-accrual status, any interest accrued but not received is reversed against interest income. Payments received on a non-accrual loan are either applied to the outstanding principal balance or recorded as interest income, depending on an assessment of the ability to collect the loan. Non-accruing loans are returned to accrual status after there has been a sustained period of repayment performance (generally six consecutive months of payment) and both principal and interest are deemed collectible. The Company identifies loans which may need to be charged-off as a loss, by reviewing all delinquent loans, classified loans and other loans that management may have concerns about collectability. An impaired loan is defined as a loan for which it is probable, based on current information, that the Bank will not collect all amounts due under the contractual terms of the loan agreement. The Bank considers the population of loans in its impairment analysis to include all multifamily and commercial real estate, construction, and commercial business loans with an outstanding balance greater than $500,000 and not accruing interest, and loans modified in a troubled debt restructuring. The Company also considers residential real estate, and home equity loans and advances that are not accruing or modified in a troubled debt restructuring for impairment. Other loans may be included in the population of loans in its impairment analysis if management has specific information of a collateral shortfall. Loan impairment is measured based on the present value of expected future cash flows discounted at the loan's effective interest rate or, as a practical expedient, at the loan's observable market price or the fair value of the collateral if the loan is collateral dependent. Payments received on impaired loans are recognized on a cash basis. Purchased Credit-Impaired ("PCI") Loans Purchased credit impaired loans are loans acquired through acquisitions at a discount primarily due to deteriorated credit quality. PCI loans are recorded at fair value at the date of acquisition, based upon the present value of expected future cash flows, with no carryover of the related allowance for credit losses. Determining the fair value of the loans involves projecting the amount and timing of principal and/or interest cash flows expected to be collected on the loans discounting those cash flows at a market rate of interest. The excess of cash flows expected at acquisition over the estimated fair value is referred to as the accretable yield and is recognized into interest income over the remaining life of the loan. The difference between contractually required payments at acquisition and the cash flows expected to be collected at acquisition is referred to as the nonaccretable yield. The nonaccretable yield represents estimated future credit losses expected to be incurred over the life of the loan. Subsequent decreases to the expected cash flows require us to evaluate the need for an allowance for credit losses. Subsequent improvements in expected cash flows result in the reversal of a corresponding amount of the nonacretable yield which we then reclassify as accretable yield that is recognized into interest income over the remaining life of the loan using the interest method. The evaluation of the amount of future cash flows that is expected to be collected is performed in a similar manner used to determine the allowance for loan losses. Any charge-offs of principal on acquired loans would first be applied against the nonaccretable yield portion of the fair value adjustment. (2) Summary of Significant Accounting Policies (continued) Allowance for Loan Losses Losses on loans are charged to the allowance for loan losses. Additions to this allowance are made by recoveries of loans previously charged off and by a provision charged to expense. The determination of the balance of the allowance for loan losses is based on an analysis of the loan portfolio, economic conditions, historical loan loss experience and other factors that warrant recognition in providing an adequate allowance. Estimates and judgments required to establish the allowance include: overall economic environment; value of collateral; strength of guarantors; loss exposure in the event of default; the amount and timing of future cash flows on impaired loans; and determination of loss factors applied to the portfolio segments. These estimates are susceptible to significant change. Management regularly reviews loss experience within the portfolio and monitors current economic conditions and other factors related to the collectability of the loan portfolio. While management uses available information, future additions to the allowance may be necessary based on changes in economic conditions in the Bank's market area. In addition, regulatory agencies, as an integral part of their examination process, periodically review the adequacy of the Bank's allowance for loan losses as an integral part of their examination. Such agencies may require the Bank to recognize additions to the allowance or additional write-downs based on their judgments about information available to them at the time of their examination. Although management uses the best information available, the level of the allowance for loan losses remains an estimate that is subject to significant uncertainties. Troubled Debt Restructuring Troubled debt restructured loans are those loans where the Company has granted a concession it would not otherwise consider because of economic or legal reasons pertaining to a debtor’s financial difficulties. A concession could include a reduced interest rate below a market rate, an extension of the term of the loan, or a combination of the two methods, but generally does not result in the forgiveness of principal or accrued interest. Not all concessions granted by the Company constitute a troubled debt restructuring. Once an obligation has been restructured and designated as a troubled debt restructuring, it continues to be designed as a restructured loan until paid in full. The Company records an impairment charge equal to the difference between the present value of expected future cash flows under the restructured terms discounted at the loan’s original effective interest rate, and the loan’s carrying value. Changes in the calculated impairment due to the passage of time are recorded as an adjustment to the allowance for loan losses. Restructured loans that were accruing prior to the restructuring, where income was reasonably assured subsequent to the restructuring, maintain their accrual status. Restructured loans for which collectability was not reasonably assured are placed on non-accrual status, interest accruals cease, and uncollected accrued interest is reversed and charged against current income. Non-accruing restructured loans may be returned to accrual status when there is a sustained period of repayment performance (generally six consecutive months of payments), and both principal and interest are deemed collectible. In March 2020, various regulatory agencies, including the Board of Governors of the Federal Reserve System and the Federal Deposit Insurance Corporations issued an interagency statement on loan modifications and reporting for financial institutions working with customers affected by COVID-19. The interagency statement was effective immediately and impacted accounting for loan modifications. Section 4013 of the CARES Act, “Temporary Relief from Troubled Debt Restructurings,” allows banks to temporarily suspend certain requirements under GAAP related to TDRs for a limited period of time to account for the effects of COVID-19. The Bank elected to account for modifications on certain loans under Section 4013 of the CARES Act or, if the loan modification was not eligible under Section 4013, used the criteria in the COVID-19 guidance to determine when the loan modification was not a TDR in accordance with ASC 310-40. Guidance noted that modification or deferral programs mandated by the federal or a state government related to COVID-19 would not be in the scope of ASC 310-40, such as a state program that requires all institutions within that state to suspend mortgage payments for a specified period. Furthermore, based on current evaluations, generally, we have continued the accrual of interest on these loans during the short-term modification period. The Consolidated Appropriations Act, 2021, which was enacted in late December 2020, extended certain provisions of the CARES Act, including provisions permitting loan deferral extension requests to not be treated as troubled debt restructurings. Loans Sold and Serviced The Company has entered into Guarantor Swaps with Freddie Mac to improve its liquidity. In these types of transactions, the Company sells mortgage loans in exchange for Freddie Mac Mortgage Participation Certificates backed exclusively by the loans sold. The Company retains the servicing of these loans. The Company also periodically sells loans to investors and continues to service such loans for a fee. Gains or losses on the sale of loans are recorded on trade date using the specific-identification method. (2) Summary of Significant Accounting Policies (continued) Office Properties and Equipment Land is carried at cost. Office properties, land and building improvements, furniture and equipment, and leasehold improvements are carried at cost, less accumulated depreciation and amortization. Depreciation and amortization of office properties and equipment is computed on a straight-line basis over their estimated useful lives (generally 40 years for buildings, 10 years to 20 years for land and building improvements, 3 years to 10 years for furniture and equipment). Leasehold improvements, carried at cost, net of accumulated depreciation, are amortized over the terms of the related leases or the estimated useful lives of the assets, whichever is shorter. Major improvements are capitalized, while repairs and maintenance costs are charged to expense as incurred. Upon retirement or sale, any gain or loss is recognized as incurred. At December 31, 2020 and 2019, land and buildings include property acquired from Stewardship with a fair value of $1.9 million and $1.8 million which is held-for-sale. Bank-owned Life Insurance ("BOLI") Bank-owned life insurance is accounted for using the cash surrender value method and is recorded at its net realizable value. The change in the net asset value is recorded as a component of non-interest income. A deferred liability has been recorded for the estimated cost of post-retirement life insurance benefits accruing to applicable employees and directors covered by an endorsement split-dollar life insurance arrangement. Goodwill and Intangible Assets Intangible assets of the Bank consist of goodwill, core deposit intangibles and mortgage servicing rights. Goodwill represents the excess of the purchase price over the fair value of net assets acquired in purchase acquisitions. In accordance with GAAP, goodwill with an indefinite useful life is not amortized, but is evaluated for impairment on an annual basis, or more frequently if events or changes in circumstances indicate potential impairment between annual measurement dates. As permitted by GAAP, the Company prepares a qualitative assessment in determining whether goodwill may be impaired. The factors considered in the assessment include macroeconomic conditions, industry and market conditions and overall financial performance of the Company, among others. The Company completed its annual goodwill impairment test as of December 31, 2020 based upon its qualitative assessment of goodwill and concluded that goodwill was not impaired and no further quantitative analysis was warranted. Core deposit intangibles represent the balance of the core deposit intangibles ascribed to the value of deposits acquired by the Bank through the acquisition of Stewardship. Mortgage servicing rights are recorded when purchased or when originated mortgage loans are sold, with servicing rights retained. Mortgage servicing rights are amortized on an accelerated method based upon the estimated lives of the related loans, and generally adjusted for prepayments. Mortgage servicing rights are carried at the lower of amortized cost or fair value. Leases The Company determines if an arrangement is a lease at inception. The Company's leases primarily relate to real estate property for branches and office space. All the Company's leases are classified as operating leases and the related right-of-use asset ("ROU") and lease liability are included in other assets other liabilities ROU assets represent the Company’s right to use an underlying asset for the lease term, and lease liabilities represent the Company’s obligation to make lease payments arising from the lease arrangements. The calculated amounts of the ROU asset and lease liabilities are impacted by the length of the lease term and the discount rate used to calculate the present value of minimum lease payments. As the Company's leases do not provide an implicit rate, the discount rate used in determining the lease liability for each individual lease is the Company's incremental borrowing rate. The present value of the lease liability may include the impact of options to extend or terminate the lease when it is reasonably certain that the Company will exercise such options provided in the lease terms. Lease expense is recognized on a straight-line basis over the expected lease term. Lease agreements that include lease and non-lease components, such as common area maintenance charges, are accounted for separately. (2) Summary of Significant Accounting Policies (continued) Post-retirement Benefits The Company provides certain health care and life insurance benefits to eligible retired employees under a Post-retirement Plan, along with a split-dollar BOLI death benefit. The Company accrues the cost of retiree health care and other benefits during the employees’ period of active service. Effective January 1, 2019, the Post-retirement plan has been closed to new hires. Effective January 1, 2019, the Company implemented ASU 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Post-retirement Benefit Cost. Under this ASU, the FASB requires employers to report the service cost component in the same line item as other compensation costs arising from services rendered by the pertinent employees during the period. The other components of net periodic benefit cost are required to be presented in the Consolidated Statements of Income separately from the service cost component. This ASU is also required to be applied retrospectively to all periods presented. Employee Benefit Plans The Company maintains a single-employer tax-qualified defined benefit pension plan (the "Pension Plan") which covers full-time employees that satisfy the Pension Plan eligibility requirements. Effective October 1, 2018, employees hired by the Bank are not eligible to participate in the Company's Pension Plan as the plan has been closed to new employees as of that date. The Company's policy is to fund at least the minimum contribution required by the Employee Retirement Income Security Act of 1974. GAAP requires an employer to: (a) recognize in its statement of financial position the over-funded or under-funded status of a defined benefit post-retirement plan measured as the difference between the fair value of plan assets and the benefit obligation; (b) measure a plan’s assets and its obligations that determine its funded status at the end of the employer’s fiscal year (with limited exceptions); and (c) recognize as a component of other comprehensive income (loss), net of tax, the actuarial gains and losses and the prior service costs and credits that arise during the period. The assets of the plan are primarily invested in fixed income and equity funds. The Company has a retirement income maintenance plan (the "RIM Plan") which is a non-qualified defined benefit plan which provides benefits to all employees of the Company if their benefits under the Pension Plan are limited by the Internal Revenue Code. The Company has a 401(k) plan covering substantially all employees of the Company. The Company may match a percentage of the first 3.00% to 4.50% contributed by participants. The Company's matching contribution, if any, is determined by the Board of Directors in its sole discretion. The Company has an Employee Stock Ownership Plan ("ESOP"). The funds borrowed by the ESOP from the Company to purchase the Company's common stock are being repaid from the Bank's contributions over a period of 20 years. The Company's common stock not allocated to participants is recorded as a reduction of stockholders' equity at cost. Compensation expense for the ESOP is based on the average price of the Company's stock and the amount of shares committed to be allocated during each period. The Company has a Supplemental Executive Retirement Plan ("SERP"). The SERP is a non-qualified plan which provides supplemental retirement benefits to eligible officers (those designated by the Board of Directors) of the Company who are prevented from receiving the full benefits contemplated by the ESOP's benefit formulas under tax law limits for tax-qualified plans. In addition, the Company maintains a stock based deferral plan (the "Stock Based Deferral Plan") for certain executives and directors. The Company records a deferred compensation equity account and corresponding contra-equity account for the cost of the shares held by the Stock Based Deferral and SERP Plans. The Company also maintains a non-qualified savings income maintenance deferred compensation plan (the "SIM Plan") that provides supplemental benefits to certain executives who are prevented from receiving the full benefits contemplated by the 401(k) Plan under tax law limits for tax-qualified plans, and a Deferred Compensation Plan for directors. (2) Summary of Significant Accounting Policies (continued) Derivatives The Company uses derivative financial instruments as components of its market risk management, principally to manage interest rate risk. Certain derivatives are entered into in connection with transactions with commercial customers. Derivatives are not used for speculative purposes. All derivatives are recognized as either assets or liabilities in the Consolidated Statements of Financial Condition, reported at fair value and presented on a gross basis. Until a derivative is settled, a favorable change in fair value results in an unrealized gain that is recognized as an asset, while an unfavorable change in fair value results in an unrealized loss that is recognized as a liability. The Company generally applies hedge accounting to its derivatives used for market risk management purposes. Hedge accounting is permitted only if specific criteria are met, including a requirement that a highly effective relationship exists between the derivative instrument and the hedged item, both at inception of the hedge and on an ongoing basis. Changes in the fair value of effective fair value hedges are recognized in current earnings (with the change in fair value of the hedged asset or liability also recognized in earnings). Changes in the fair value of effective cash flow hedges are recognized in other comprehensive income (loss) until earnings are affected by the variability in cash flows of the designated hedged item. Ineffective portions of hedge results are recognized in current earnings. Changes in the fair value of derivatives for which hedge accounting is not applied are recognized in current earnings. The Company formally documents at inception all relationships between the derivative instruments and the hedged items, as well as its risk management objectives and strategies for undertaking the hedge transactions. This process includes linking all derivatives that are designated as hedges to specific assets and liabilities, or to specific firm commitments. The Company also formally assesses, both at inception of the hedge and on an ongoing basis, whether the derivatives that are used in hedging transactions are highly effective in offsetting changes in the fair values or cash flows of the hedged items. If it is determined that a derivative is not highly effective or has ceased to be a highly effective hedge, the Company would discontinue hedge accounting prospectively. Gains or losses resulting from the termination of a derivative accounted for as a cash flow hedge remain in other comprehensive income (loss) and is (accreted) amortized to earnings over the remaining period of the former hedging relationship. Certain derivative financial instruments are offered to certain commercial banking customers to manage their risk of exposure and risk management strategies. These derivative instruments consist primarily of currency forward contracts and interest rate swap contracts. The risks associated with these transactions is mitigated by simultaneously entering into similar transactions having essentially offsetting terms with a third party. In addition, the Company executes interest rate swaps with third parties in order to hedge the interest rate risk of short-term FHLB advances. Income Taxes The Company and its subsidiaries file consolidated federal income tax returns. Federal income taxes are allocated to each entity based on their respective contributions to taxable income of the consolidated income tax returns. Beginning in 2019 as required by the State of New Jersey, the Company adopted combined income tax reporting for certain members of a commonly-controlled unitary business group. Prior to 2019, separate state income tax returns were filed for the Company and each of its qualifying subsidiaries. The Company records income taxes in accordance with ASC Topic 740, Income Taxes , using the asset and liability method. The amounts reflected on the Company's federal and state income tax returns differ from these provisions due principally to temporary differences in the reporting of certain items for consolidated financial statement reporting and income tax reporting purposes. Accordingly, deferred tax assets and liabilities: (i) are recognized for the expected future tax consequences of events that have been recognized in the financial statements or tax returns; (ii) are attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases; and (iii) are measured using enacted tax rates expected to apply in the years when those temporary differences are expected to be recovered or settled. Where applicable, deferred tax assets are reduced by a valuation allowance for any portions determined not likely to be realized. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income tax expense in the period that includes the enactment date. The valuation allowance is adjusted, by a

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
Acquisitions	Acquisitions Stewardship Financial Corporation On November 1, 2019, the Company completed its acquisition of Stewardship Financial Corporation ("Stewardship"), pursuant to the Agreement and Plan of Merger, dated as of June 6, 2019, (the "Merger Agreement"). Under the terms of the merger agreement, each outstanding share of Stewardship common stock was converted into the right to receive $15.75 in cash at the effective time of the merger. At the time of closing, Stewardship had $956.0 million in total assets, including $756.9 million in net loans receivable, $52.6 million in securities, and $877.8 million in total liabilities, including $781.4 million in deposits and $81.8 million in borrowings. The deposits initially acquired from Stewardship were held across a network of 12 branches located in New Jersey throughout Bergen, Morris, and Passaic counties. During the year ended December 31, 2020, four of these branches were closed, and the Bank recorded a loss of $770,000 related to these branch closures. Merger-related expenses are recorded in the Consolidated Statements of Income and are expensed as incurred. Direct acquisition and other charges incurred in connection with the Stewardship acquisition totaled $1.3 million and $2.8 million for the years ended December 31, 2020 and 2019, respectively. The following table sets forth assets acquired and liabilities assumed in the Stewardship acquisition, at their estimated fair values as of the closing date of the transaction: November 1, 2019 Assets acquired: Cash and cash equivalents $ 105,006 Debt securities available for sale 51,710 Equity securities 1,073 Federal Home Loan Bank stock 3,716 Loans receivable 757,223 Accrued interest receivable 2,239 Office properties and equipment, net 6,815 Bank-owned life insurance 22,096 Deferred tax assets, net 3,534 Core deposit and other intangibles 7,467 Other assets 767 Total assets acquired $ 961,646 Liabilities assumed: Deposits $ 782,698 Borrowings 82,761 Advance payments by borrowers for taxes and insurance 356 Accrued expenses and other liabilities 14,584 Total liabilities assumed $ 880,399 Net assets acquired $ 81,247 Cash paid for purchase 136,294 Goodwill recorded at merger $ 55,047 The assets acquired and liabilities assumed have been accounted for under the acquisition method of accounting. The assets and liabilities were recorded at their fair values as of November 1, 2019, and resulted in the recognition of goodwill of $55.0 million and a core deposit intangible of $7.5 million. The determination of the fair value of assets acquired and liabilities assumed required management to make estimates about discount rates, future expected cash flows, market conditions, and other future events that are highly subjective in nature and subject to change. The fair value estimates were subject to change for up to one year after the closing date of the transaction if additional information (existing at the date of closing) relative to closing date fair values became available. During the year ended December 31, 2020, the Company determined that there were no material adjustments required to be recorded to amounts as of November 1, 2019. (3) Acquisitions (continued) Roselle Bank On April 1, 2020, the Company completed its acquisition of RSB Bancorp, MHC, RSB Bancorp, Inc. and Roselle Bank (collectively, the "Roselle Entities" or "Roselle"). Pursuant to the terms of the Merger Agreement, RSB Bancorp, MHC merged with and into the MHC, with the MHC as the surviving entity; RSB Bancorp, Inc. merged with and into Columbia Financial, with Columbia Financial as the surviving entity; and Roselle Bank merged with and into the Bank, with the Bank as the surviving institution. Under the terms of the merger agreement, depositors of Roselle Bank became depositors of the Bank and have the same rights and privileges in the MHC as if their accounts had been established at the Bank on the date established at Roselle Bank. The Company issued 4,759,048 shares of its common stock to the MHC, representing an amount equal to the fair value of the Roselle Entities as determined by an independent appraiser, at the effective time of the merger. Merger-related expenses are recorded in the Consolidated Statements of Income and are expensed as incurred. Direct acquisition and other charges incurred in connection with the Roselle acquisition totaled $597,000 for the year ended December 31, 2020. There were no expenses related to this merger recorded for the year ended December 31, 2019. The following table sets forth assets acquired and liabilities assumed in the Stewardship acquisition, at their estimated fair values as of the closing date of the transaction: April 1, 2020 Assets acquired: Cash and cash equivalents $ 155,248 Debt securities available for sale 51,479 Debt securities held to maturity 13,418 Equity securities 1,796 Federal Home Loan Bank stock 2,010 Loans receivable 171,593 Accrued interest receivable 679 Office properties and equipment, net 5,774 Bank-owned life insurance 17,245 Deferred tax assets, net 1,334 Other assets 1,489 Total assets acquired $ 422,065 Liabilities assumed: Deposits $ 333,234 Borrowings 37,728 Advance payments by borrowers for taxes and insurance 982 Accrued expenses and other liabilities 5,400 Total liabilities assumed $ 377,344 Net assets acquired $ 44,721 Fair market value of stock issued to Columbia Bank MHC for purchase 68,530 Goodwill recorded at merger $ 23,809 (3) Acquisitions (continued) Roselle Bank (continued) The assets acquired and liabilities assumed have been accounted for under the acquisition method of accounting. The assets and liabilities were recorded at their fair values as of April 1, 2020, and resulted in the recognition of goodwill of $23.8 million. The determination of the fair value of assets acquired and liabilities assumed required management to make estimates about discount rates, future expected cash flows, market conditions, and other future events that are highly subjective in nature and subject to change. The fair value estimates are subject to change for up to one year after the closing date of the transaction if additional information (existing at the date of closing) relative to closing date fair values becomes available. During the fourth quarter of 2020, the Company completed all tax returns related to the operation of the acquired entity and its impact on the Company's income taxes, which resulted in a $5.1 million adjustment to deferred income taxes, net, and a decrease in goodwill. At December 31, 2020, goodwill related to the Roselle acquisition totaled $18.7 million. As the Company continues to analyze the acquired assets and assumed liabilities, there may be adjustments to the recorded carrying values through April 1, 2021. Fair Value Measurement of Assets Acquired and Liabilities Assumed Described below are the methods used to determine the fair values of the significant assets acquired and liabilities assumed in the Stewardship and Roselle acquisitions: Cash and cash equivalents. The estimated fair values of cash and cash equivalents approximate their stated face amounts, as these financial instruments are either due on demand or have short-term maturities. Debt securities available for sale. The estimated fair values of the debt securities were calculated utilizing Level 2 inputs. The majority of the acquired securities were fixed income instruments that are not quoted on an exchange, but are traded in active markets. The prices for these instruments are obtained through an independent pricing service when available, or dealer market participants with whom the Company has historically transacted with for both purchases and sales of securities. The prices are derived from market quotations and matrix pricing. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, and the bond's terms and conditions, among other things. Management reviewed the data and assumptions used in pricing securities by its third party provider to ensure the highest level of significant inputs are derived from market observable data. Loans receivable. The acquired loan portfolio was segregated into pools for valuation purposes primarily based on loan type, non-accrual status, and credit risk rating. The estimated fair values were computed by discounting the expected cash flows from the respective pools. Cash flows were estimated by using valuation models that incorporated estimates of current key assumptions such as prepayment speeds, default rates, and loss severity rates. The process included: (1) projecting monthly principal and/or interest cash flows based on the contractual terms of the loans, including both maturity and contractual amortization; (2) adjusting projected cash flows for expected losses and prepayments, where appropriate; (3) developing a discount rate based on the relative risk of the cash flows, considering the loan type, liquidity risk, the maturity of the loans, servicing costs, and a required return on capital; and (4) discounting the projected cash flows to a present value, to arrive at the calculated value of the loans. The methods used to estimate the fair values of loans are extremely sensitive to the assumptions and estimates used. While management attempted to use assumptions and estimates that best reflected the acquired loan portfolios and current market conditions, a greater degree of subjectivity is inherent in the values than in those determined in active markets. Office properties and equipment, net. The fair value of land and buildings was estimated using current appraisals. Acquired equipment was not material. Buildings are amortized over their estimated useful lives. Leasehold improvements and equipment are amortized or depreciated over their estimated useful lives usually ranging for 3 years to 10 years. Goodwill and intangible assets. Goodwill is not amortized for book purposes: however: it is reviewed at least annually for impairment and is not deductible for tax purposes. Intangible assets recognized in the Stewardship acquisition consisting of core deposit intangibles ("CDI") are the measures of the value of non-maturity deposits in a business combination. The fair value of the CDI was calculated utilizing the cost savings approach, the expected cost savings attributable to the core deposits funding relative to an alternative source of funding, using a discounted cash flow present value methodology. Key inputs and assumptions utilized in the discounted cash flow present value methodology include core deposit balances and rates paid, the cost of an additional funding source, the aggregate life of deposits and truncation points, non-interest deposit costs, and the immediate deposit outflow assumption. The CDI is amortized over an estimated useful life of 10 years to approximate the existing deposit relationships acquired. (3) Acquisitions (continued) Fair Value Measurement of Assets Acquired and Liabilities Assumed (continued) Deposits. The fair values of deposit liabilities with no stated maturity (i.e., non-interest bearing and interest-bearing demand deposit accounts, money market and savings and club accounts) are equal to the carrying amounts payable on demand. The fair value of certificates of deposit represent contractual cash flows, discounted to present value using interest rates currently offered on deposits with similar characteristics and remaining maturities. Borrowings. The fair values of borrowings consisting of FHLB advances were estimated by discounting future cash flows using market discount rates for borrowings with similar characteristics, terms and remaining maturities. The fair value of other borrowings recognized in the Stewardship acquisition, which included subordinated notes and debentures, were measured at the acquisition date using a dealer market quote.

Debt Securities Available for S

Debt Securities Available for Sale	12 Months Ended
	Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Debt Securities Available for Sale	Debt Securities Available for Sale Debt s ecurities available for sale at December 31, 2020 and 2019 are summarized as follows: December 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (In thousands) U.S. government and agency obligations $ 24,425 $ 1,124 $ — $ 25,549 Mortgage-backed securities and collateralized mortgage obligations 1,163,613 37,343 (562) 1,200,394 Municipal obligations 16,845 17 — 16,862 Corporate debt securities 67,628 2,264 (415) 69,477 Trust preferred securities 5,000 — (330) 4,670 $ 1,277,511 $ 40,748 $ (1,307) $ 1,316,952 December 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (In thousands) U.S. government and agency obligations $ 42,081 $ 321 $ (16) $ 42,386 Mortgage-backed securities and collateralized mortgage obligations 968,165 12,981 (1,265) 979,881 Municipal obligations 2,284 1 (1) 2,284 Corporate debt securities 68,613 945 (378) 69,180 Trust preferred securities 5,000 — (395) 4,605 $ 1,086,143 $ 14,248 $ (2,055) $ 1,098,336 The amortized cost and fair value of debt securities available for sale at December 31, 2020, by contractual final maturity, is shown below. Expected maturities may differ from contractual maturities due to prepayment or early call options exercised by the issuer. (4) Debt Securities Available for Sale (continued) December 31, 2020 Amortized Cost Fair Value (In thousands) One year or less $ 21,378 $ 21,380 More than one year to five years 47,429 49,276 More than five years to ten years 45,091 45,902 $ 113,898 $ 116,558 Mortgage-backed securities and collateralized mortgage obligations 1,163,613 1,200,394 $ 1,277,511 $ 1,316,952 Mortgage-backed securities and collateralized mortgage obligations totaling $1.2 billion at amortized cost, and $1.2 billion at fair value, are not classified by maturity in the table above as their expected lives are likely to be shorter than the contractual maturity date due to principal prepayments. During the year ended December 31, 2020, proceeds from the sale of debt securities available for sale totaled $20.8 million, resulting in $369,000 of gross gains and no gross losses. During the year ended December 31, 2020, proceeds from called debt securities available for sale totaled $11.6 million resulting in $1,000 of gross gains and no gross losses. During the year ended December 31, 2020, proceeds from matured debt securities available for sale totaled $10.9 million. During the year ended December 31, 2019, proceeds from the sale of debt securities available for sale totaled $65.2 million, resulting in $2.2 million of gross gains and $22,000 of gross losses. During the year ended December 31, 2019, proceeds from called debt securities available for sale totaled $24.1 million resulting in $174,000 of gross gains and no gross losses. During the year ended December 31, 2019, proceeds from one matured debt security available for sale totaled $797,000. During the year ended December 31, 2018, proceeds from the sale of debt securities available for sale totaled $11.5 million, resulting in $116,000 of gross gains and no gross losses. During the year ended December 31, 2018, proceeds from matured debt securities available for sale totaled $2.4 million. Debt securities available for sale having a carrying value of $822.2 million and $462.0 million, at December 31, 2020 and 2019, respectively, were pledged as security for public funds on deposit at the Bank as required and permitted by law, pledged for outstanding borrowings at the Federal Home Loan Bank, and pledged for potential borrowings at the Federal Reserve Bank of New York. The following tables summarize the fair value and gross unrealized losses of those securities that reported an unrealized loss at December 31, 2020 and 2019 and if the unrealized loss position was continuous for the twelve months prior to those respective dates: December 31, 2020 Less Than 12 Months 12 Months or Longer Total Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) (In thousands) Mortgage-backed securities and collateralized mortgage obligations $ 117,978 $ (481) $ 24,018 $ (81) $ 141,996 $ (562) Corporate debt securities 9,845 (155) 5,740 (260) 15,585 (415) Trust preferred securities — — 4,670 (330) 4,670 (330) $ 127,823 $ (636) $ 34,428 $ (671) $ 162,251 $ (1,307) (4) Debt Securities Available for Sale (continued) December 31, 2019 Less Than 12 Months 12 Months or Longer Total Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) (In thousands) U.S. government and agency obligations $ 5,106 $ (13) $ 4,988 $ (3) $ 10,094 $ (16) Mortgage-backed securities and collateralized mortgage obligations 178,665 (946) 58,208 (319) 236,873 (1,265) Municipal obligations 696 (1) — — 696 (1) Corporate debt securities 2,588 (5) 4,627 (373) 7,215 (378) Trust preferred securities — — 4,605 (395) 4,605 (395) $ 187,055 $ (965) $ 72,428 $ (1,090) $ 259,483 $ (2,055) The Company evaluates securities for other-than-temporary impairment at each reporting period and more frequently when economic or market conditions warrant such evaluation. The temporary loss position associated with debt securities available for sale was the result of changes in market interest rates relative to the coupon of the individual security and changes in credit spreads. The Company does not have the intent to sell securities in a temporary loss position at December 31, 2020, nor is it more likely than not that the Company will be required to sell the securities before the anticipated recovery. The number of securities in an unrealized loss position at December 31, 2020 totaled 40, compared with 97 at December 31, 2019. All temporarily impaired securities were investment grade as of December 31, 2020 and 2019. The Company did not record an other-than-temporary impairment charge on debt securities available for sale during the years ended December 31, 2020, 2019, and 2018. Debt securities held to maturity at December 31, 2020 and 2019 are summarized as follows: December 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (In thousands) U.S. government and agency obligations $ 5,000 $ 1 $ — $ 5,001 Mortgage-backed securities and collateralized mortgage obligations 257,720 14,372 (2) 272,090 $ 262,720 $ 14,373 $ (2) $ 277,091 December 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (In thousands) U.S. government and agency obligations $ 20,000 $ 26 $ (66) $ 19,960 Mortgage-backed securities and collateralized mortgage obligations 265,756 4,048 (259) 269,545 $ 285,756 $ 4,074 $ (325) $ 289,505 (5) Debt Securities Held to Maturity (continued) The amortized cost and fair value of debt securities held to maturity at December 31, 2020, by contractual final maturity, is shown below. Expected maturities may differ from contractual maturities due to prepayment or early call options exercised by the issuer. December 31, 2020 Amortized Cost Fair Value (In thousands) More than one year to five years $ 5,000 $ 5,001 Mortgage-backed securities and collateralized mortgage obligations 257,720 272,090 $ 262,720 $ 277,091 Mortgage-backed securities and collateralized mortgage obligations totaling $257.7 million at amortized cost, and $272.1 million at fair value at December 31, 2020, are not classified by maturity in the table above as their expected lives are likely to be shorter than the contractual maturity date due to principal prepayments. During the year ended December 31, 2020, there were no sales of debt securities held to maturity. During the year ended December 31, 2020, proceeds from called debt securities held to maturity totaled $20.0 million. No gross gains or losses were recognized on the securities which were called. There were no sales of debt securities held to maturity for the years ended December 31, 2019 and 2018. During the year ended December 31, 2019, proceeds from called debt securities held to maturity totaled $33.4 million, resulting in $24,000 of gross gains and no gross losses. During the year ended December 31, 2018, proceeds from calls and maturities of debt securities held to maturity totaled $5.4 million, resulting in no gross gains or losses. Debt securities held to maturity having a carrying value of $220.5 million and $236.0 million, at December 31, 2020 and December 31, 2019, respectively, were pledged as security for public funds on deposit at the Bank as required and permitted by law, pledged for outstanding borrowings at the Federal Home Loan Bank, and pledged for potential borrowings at the Federal Reserve Bank of New York. The following tables summarize the fair value and gross unrealized losses of those securities that reported an unrealized loss at December 31, 2020 and 2019 and if the unrealized loss position was continuous for the twelve months prior to those respective dates: December 31, 2020 Less Than 12 Months 12 Months or Longer Total Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) (In thousands) Mortgage-backed securities and collateralized mortgage obligations $ 2,176 $ (2) $ — $ — $ 2,176 $ (2) (5) Debt Securities Held to Maturity (continued) December 31, 2019 Less than 12 months 12 months or longer Total Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) (In thousands) U.S. government and agency obligations $ 9,934 $ (66) $ — $ — $ 9,934 $ (66) Mortgage-backed securities and collateralized mortgage obligations 27,911 (251) 772 (8) 28,683 (259) $ 37,845 $ (317) $ 772 $ (8) $ 38,617 $ (325) The Company evaluates securities for other-than-temporary impairment at each reporting period and more frequently when economic or market conditions warrant such evaluation. The temporary loss position associated with debt securities held to maturity was the result of changes in market interest rates relative to the coupon of the individual security and changes in credit spreads. The Company does not have the intent to sell securities in a temporary loss position at December 31, 2020, nor is it more likely than not that the Company will be required to sell the securities before the anticipated recovery. There were two securities in an unrealized loss position as of December 31, 2020, compared with 22 at December 31, 2019. All temporarily impaired securities were investment grade as of December 31, 2020 and 2019. The Company did not record an other-than-temporary impairment charge on debt securities held to maturity for the years ended December 31, 2020, 2019, and 2018. The Company has an equity securities portfolio which consists of stock in other financial institutions, a payment technology company, a community bank correspondent services company, and preferred stock in U.S. Government agencies which are reported at fair value on the Company's Consolidated Statements of Financial Condition. The fair value of the equities portfolio at December 31, 2020 and 2019 was $5.4 million and $2.9 million, respectively. The Company adopted ASU 2016-01 on January 1, 2019, resulting in a $548,000 after tax cumulative-effect adjustment from other comprehensive income (loss) to retained earnings, as reflected in the Consolidated Statements of Changes in Stockholders' Equity. The Company recorded a net increase in the fair value of equity securities of $767,000 and $305,000 for the years ended December 31, 2020 and 2019, respectively, as a component of non-interest income.

Debt Securities Held to Maturit

Debt Securities Held to Maturity	12 Months Ended
	Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Debt Securities Held to Maturity	Debt Securities Available for Sale Debt s ecurities available for sale at December 31, 2020 and 2019 are summarized as follows: December 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (In thousands) U.S. government and agency obligations $ 24,425 $ 1,124 $ — $ 25,549 Mortgage-backed securities and collateralized mortgage obligations 1,163,613 37,343 (562) 1,200,394 Municipal obligations 16,845 17 — 16,862 Corporate debt securities 67,628 2,264 (415) 69,477 Trust preferred securities 5,000 — (330) 4,670 $ 1,277,511 $ 40,748 $ (1,307) $ 1,316,952 December 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (In thousands) U.S. government and agency obligations $ 42,081 $ 321 $ (16) $ 42,386 Mortgage-backed securities and collateralized mortgage obligations 968,165 12,981 (1,265) 979,881 Municipal obligations 2,284 1 (1) 2,284 Corporate debt securities 68,613 945 (378) 69,180 Trust preferred securities 5,000 — (395) 4,605 $ 1,086,143 $ 14,248 $ (2,055) $ 1,098,336 The amortized cost and fair value of debt securities available for sale at December 31, 2020, by contractual final maturity, is shown below. Expected maturities may differ from contractual maturities due to prepayment or early call options exercised by the issuer. (4) Debt Securities Available for Sale (continued) December 31, 2020 Amortized Cost Fair Value (In thousands) One year or less $ 21,378 $ 21,380 More than one year to five years 47,429 49,276 More than five years to ten years 45,091 45,902 $ 113,898 $ 116,558 Mortgage-backed securities and collateralized mortgage obligations 1,163,613 1,200,394 $ 1,277,511 $ 1,316,952 Mortgage-backed securities and collateralized mortgage obligations totaling $1.2 billion at amortized cost, and $1.2 billion at fair value, are not classified by maturity in the table above as their expected lives are likely to be shorter than the contractual maturity date due to principal prepayments. During the year ended December 31, 2020, proceeds from the sale of debt securities available for sale totaled $20.8 million, resulting in $369,000 of gross gains and no gross losses. During the year ended December 31, 2020, proceeds from called debt securities available for sale totaled $11.6 million resulting in $1,000 of gross gains and no gross losses. During the year ended December 31, 2020, proceeds from matured debt securities available for sale totaled $10.9 million. During the year ended December 31, 2019, proceeds from the sale of debt securities available for sale totaled $65.2 million, resulting in $2.2 million of gross gains and $22,000 of gross losses. During the year ended December 31, 2019, proceeds from called debt securities available for sale totaled $24.1 million resulting in $174,000 of gross gains and no gross losses. During the year ended December 31, 2019, proceeds from one matured debt security available for sale totaled $797,000. During the year ended December 31, 2018, proceeds from the sale of debt securities available for sale totaled $11.5 million, resulting in $116,000 of gross gains and no gross losses. During the year ended December 31, 2018, proceeds from matured debt securities available for sale totaled $2.4 million. Debt securities available for sale having a carrying value of $822.2 million and $462.0 million, at December 31, 2020 and 2019, respectively, were pledged as security for public funds on deposit at the Bank as required and permitted by law, pledged for outstanding borrowings at the Federal Home Loan Bank, and pledged for potential borrowings at the Federal Reserve Bank of New York. The following tables summarize the fair value and gross unrealized losses of those securities that reported an unrealized loss at December 31, 2020 and 2019 and if the unrealized loss position was continuous for the twelve months prior to those respective dates: December 31, 2020 Less Than 12 Months 12 Months or Longer Total Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) (In thousands) Mortgage-backed securities and collateralized mortgage obligations $ 117,978 $ (481) $ 24,018 $ (81) $ 141,996 $ (562) Corporate debt securities 9,845 (155) 5,740 (260) 15,585 (415) Trust preferred securities — — 4,670 (330) 4,670 (330) $ 127,823 $ (636) $ 34,428 $ (671) $ 162,251 $ (1,307) (4) Debt Securities Available for Sale (continued) December 31, 2019 Less Than 12 Months 12 Months or Longer Total Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) (In thousands) U.S. government and agency obligations $ 5,106 $ (13) $ 4,988 $ (3) $ 10,094 $ (16) Mortgage-backed securities and collateralized mortgage obligations 178,665 (946) 58,208 (319) 236,873 (1,265) Municipal obligations 696 (1) — — 696 (1) Corporate debt securities 2,588 (5) 4,627 (373) 7,215 (378) Trust preferred securities — — 4,605 (395) 4,605 (395) $ 187,055 $ (965) $ 72,428 $ (1,090) $ 259,483 $ (2,055) The Company evaluates securities for other-than-temporary impairment at each reporting period and more frequently when economic or market conditions warrant such evaluation. The temporary loss position associated with debt securities available for sale was the result of changes in market interest rates relative to the coupon of the individual security and changes in credit spreads. The Company does not have the intent to sell securities in a temporary loss position at December 31, 2020, nor is it more likely than not that the Company will be required to sell the securities before the anticipated recovery. The number of securities in an unrealized loss position at December 31, 2020 totaled 40, compared with 97 at December 31, 2019. All temporarily impaired securities were investment grade as of December 31, 2020 and 2019. The Company did not record an other-than-temporary impairment charge on debt securities available for sale during the years ended December 31, 2020, 2019, and 2018. Debt securities held to maturity at December 31, 2020 and 2019 are summarized as follows: December 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (In thousands) U.S. government and agency obligations $ 5,000 $ 1 $ — $ 5,001 Mortgage-backed securities and collateralized mortgage obligations 257,720 14,372 (2) 272,090 $ 262,720 $ 14,373 $ (2) $ 277,091 December 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (In thousands) U.S. government and agency obligations $ 20,000 $ 26 $ (66) $ 19,960 Mortgage-backed securities and collateralized mortgage obligations 265,756 4,048 (259) 269,545 $ 285,756 $ 4,074 $ (325) $ 289,505 (5) Debt Securities Held to Maturity (continued) The amortized cost and fair value of debt securities held to maturity at December 31, 2020, by contractual final maturity, is shown below. Expected maturities may differ from contractual maturities due to prepayment or early call options exercised by the issuer. December 31, 2020 Amortized Cost Fair Value (In thousands) More than one year to five years $ 5,000 $ 5,001 Mortgage-backed securities and collateralized mortgage obligations 257,720 272,090 $ 262,720 $ 277,091 Mortgage-backed securities and collateralized mortgage obligations totaling $257.7 million at amortized cost, and $272.1 million at fair value at December 31, 2020, are not classified by maturity in the table above as their expected lives are likely to be shorter than the contractual maturity date due to principal prepayments. During the year ended December 31, 2020, there were no sales of debt securities held to maturity. During the year ended December 31, 2020, proceeds from called debt securities held to maturity totaled $20.0 million. No gross gains or losses were recognized on the securities which were called. There were no sales of debt securities held to maturity for the years ended December 31, 2019 and 2018. During the year ended December 31, 2019, proceeds from called debt securities held to maturity totaled $33.4 million, resulting in $24,000 of gross gains and no gross losses. During the year ended December 31, 2018, proceeds from calls and maturities of debt securities held to maturity totaled $5.4 million, resulting in no gross gains or losses. Debt securities held to maturity having a carrying value of $220.5 million and $236.0 million, at December 31, 2020 and December 31, 2019, respectively, were pledged as security for public funds on deposit at the Bank as required and permitted by law, pledged for outstanding borrowings at the Federal Home Loan Bank, and pledged for potential borrowings at the Federal Reserve Bank of New York. The following tables summarize the fair value and gross unrealized losses of those securities that reported an unrealized loss at December 31, 2020 and 2019 and if the unrealized loss position was continuous for the twelve months prior to those respective dates: December 31, 2020 Less Than 12 Months 12 Months or Longer Total Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) (In thousands) Mortgage-backed securities and collateralized mortgage obligations $ 2,176 $ (2) $ — $ — $ 2,176 $ (2) (5) Debt Securities Held to Maturity (continued) December 31, 2019 Less than 12 months 12 months or longer Total Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) (In thousands) U.S. government and agency obligations $ 9,934 $ (66) $ — $ — $ 9,934 $ (66) Mortgage-backed securities and collateralized mortgage obligations 27,911 (251) 772 (8) 28,683 (259) $ 37,845 $ (317) $ 772 $ (8) $ 38,617 $ (325) The Company evaluates securities for other-than-temporary impairment at each reporting period and more frequently when economic or market conditions warrant such evaluation. The temporary loss position associated with debt securities held to maturity was the result of changes in market interest rates relative to the coupon of the individual security and changes in credit spreads. The Company does not have the intent to sell securities in a temporary loss position at December 31, 2020, nor is it more likely than not that the Company will be required to sell the securities before the anticipated recovery. There were two securities in an unrealized loss position as of December 31, 2020, compared with 22 at December 31, 2019. All temporarily impaired securities were investment grade as of December 31, 2020 and 2019. The Company did not record an other-than-temporary impairment charge on debt securities held to maturity for the years ended December 31, 2020, 2019, and 2018. The Company has an equity securities portfolio which consists of stock in other financial institutions, a payment technology company, a community bank correspondent services company, and preferred stock in U.S. Government agencies which are reported at fair value on the Company's Consolidated Statements of Financial Condition. The fair value of the equities portfolio at December 31, 2020 and 2019 was $5.4 million and $2.9 million, respectively. The Company adopted ASU 2016-01 on January 1, 2019, resulting in a $548,000 after tax cumulative-effect adjustment from other comprehensive income (loss) to retained earnings, as reflected in the Consolidated Statements of Changes in Stockholders' Equity. The Company recorded a net increase in the fair value of equity securities of $767,000 and $305,000 for the years ended December 31, 2020 and 2019, respectively, as a component of non-interest income.

Equity Securities at Fair Value

Equity Securities at Fair Value	12 Months Ended
	Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Equity Securities at Fair Value	Debt Securities Available for Sale Debt s ecurities available for sale at December 31, 2020 and 2019 are summarized as follows: December 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (In thousands) U.S. government and agency obligations $ 24,425 $ 1,124 $ — $ 25,549 Mortgage-backed securities and collateralized mortgage obligations 1,163,613 37,343 (562) 1,200,394 Municipal obligations 16,845 17 — 16,862 Corporate debt securities 67,628 2,264 (415) 69,477 Trust preferred securities 5,000 — (330) 4,670 $ 1,277,511 $ 40,748 $ (1,307) $ 1,316,952 December 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (In thousands) U.S. government and agency obligations $ 42,081 $ 321 $ (16) $ 42,386 Mortgage-backed securities and collateralized mortgage obligations 968,165 12,981 (1,265) 979,881 Municipal obligations 2,284 1 (1) 2,284 Corporate debt securities 68,613 945 (378) 69,180 Trust preferred securities 5,000 — (395) 4,605 $ 1,086,143 $ 14,248 $ (2,055) $ 1,098,336 The amortized cost and fair value of debt securities available for sale at December 31, 2020, by contractual final maturity, is shown below. Expected maturities may differ from contractual maturities due to prepayment or early call options exercised by the issuer. (4) Debt Securities Available for Sale (continued) December 31, 2020 Amortized Cost Fair Value (In thousands) One year or less $ 21,378 $ 21,380 More than one year to five years 47,429 49,276 More than five years to ten years 45,091 45,902 $ 113,898 $ 116,558 Mortgage-backed securities and collateralized mortgage obligations 1,163,613 1,200,394 $ 1,277,511 $ 1,316,952 Mortgage-backed securities and collateralized mortgage obligations totaling $1.2 billion at amortized cost, and $1.2 billion at fair value, are not classified by maturity in the table above as their expected lives are likely to be shorter than the contractual maturity date due to principal prepayments. During the year ended December 31, 2020, proceeds from the sale of debt securities available for sale totaled $20.8 million, resulting in $369,000 of gross gains and no gross losses. During the year ended December 31, 2020, proceeds from called debt securities available for sale totaled $11.6 million resulting in $1,000 of gross gains and no gross losses. During the year ended December 31, 2020, proceeds from matured debt securities available for sale totaled $10.9 million. During the year ended December 31, 2019, proceeds from the sale of debt securities available for sale totaled $65.2 million, resulting in $2.2 million of gross gains and $22,000 of gross losses. During the year ended December 31, 2019, proceeds from called debt securities available for sale totaled $24.1 million resulting in $174,000 of gross gains and no gross losses. During the year ended December 31, 2019, proceeds from one matured debt security available for sale totaled $797,000. During the year ended December 31, 2018, proceeds from the sale of debt securities available for sale totaled $11.5 million, resulting in $116,000 of gross gains and no gross losses. During the year ended December 31, 2018, proceeds from matured debt securities available for sale totaled $2.4 million. Debt securities available for sale having a carrying value of $822.2 million and $462.0 million, at December 31, 2020 and 2019, respectively, were pledged as security for public funds on deposit at the Bank as required and permitted by law, pledged for outstanding borrowings at the Federal Home Loan Bank, and pledged for potential borrowings at the Federal Reserve Bank of New York. The following tables summarize the fair value and gross unrealized losses of those securities that reported an unrealized loss at December 31, 2020 and 2019 and if the unrealized loss position was continuous for the twelve months prior to those respective dates: December 31, 2020 Less Than 12 Months 12 Months or Longer Total Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) (In thousands) Mortgage-backed securities and collateralized mortgage obligations $ 117,978 $ (481) $ 24,018 $ (81) $ 141,996 $ (562) Corporate debt securities 9,845 (155) 5,740 (260) 15,585 (415) Trust preferred securities — — 4,670 (330) 4,670 (330) $ 127,823 $ (636) $ 34,428 $ (671) $ 162,251 $ (1,307) (4) Debt Securities Available for Sale (continued) December 31, 2019 Less Than 12 Months 12 Months or Longer Total Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) (In thousands) U.S. government and agency obligations $ 5,106 $ (13) $ 4,988 $ (3) $ 10,094 $ (16) Mortgage-backed securities and collateralized mortgage obligations 178,665 (946) 58,208 (319) 236,873 (1,265) Municipal obligations 696 (1) — — 696 (1) Corporate debt securities 2,588 (5) 4,627 (373) 7,215 (378) Trust preferred securities — — 4,605 (395) 4,605 (395) $ 187,055 $ (965) $ 72,428 $ (1,090) $ 259,483 $ (2,055) The Company evaluates securities for other-than-temporary impairment at each reporting period and more frequently when economic or market conditions warrant such evaluation. The temporary loss position associated with debt securities available for sale was the result of changes in market interest rates relative to the coupon of the individual security and changes in credit spreads. The Company does not have the intent to sell securities in a temporary loss position at December 31, 2020, nor is it more likely than not that the Company will be required to sell the securities before the anticipated recovery. The number of securities in an unrealized loss position at December 31, 2020 totaled 40, compared with 97 at December 31, 2019. All temporarily impaired securities were investment grade as of December 31, 2020 and 2019. The Company did not record an other-than-temporary impairment charge on debt securities available for sale during the years ended December 31, 2020, 2019, and 2018. Debt securities held to maturity at December 31, 2020 and 2019 are summarized as follows: December 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (In thousands) U.S. government and agency obligations $ 5,000 $ 1 $ — $ 5,001 Mortgage-backed securities and collateralized mortgage obligations 257,720 14,372 (2) 272,090 $ 262,720 $ 14,373 $ (2) $ 277,091 December 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (In thousands) U.S. government and agency obligations $ 20,000 $ 26 $ (66) $ 19,960 Mortgage-backed securities and collateralized mortgage obligations 265,756 4,048 (259) 269,545 $ 285,756 $ 4,074 $ (325) $ 289,505 (5) Debt Securities Held to Maturity (continued) The amortized cost and fair value of debt securities held to maturity at December 31, 2020, by contractual final maturity, is shown below. Expected maturities may differ from contractual maturities due to prepayment or early call options exercised by the issuer. December 31, 2020 Amortized Cost Fair Value (In thousands) More than one year to five years $ 5,000 $ 5,001 Mortgage-backed securities and collateralized mortgage obligations 257,720 272,090 $ 262,720 $ 277,091 Mortgage-backed securities and collateralized mortgage obligations totaling $257.7 million at amortized cost, and $272.1 million at fair value at December 31, 2020, are not classified by maturity in the table above as their expected lives are likely to be shorter than the contractual maturity date due to principal prepayments. During the year ended December 31, 2020, there were no sales of debt securities held to maturity. During the year ended December 31, 2020, proceeds from called debt securities held to maturity totaled $20.0 million. No gross gains or losses were recognized on the securities which were called. There were no sales of debt securities held to maturity for the years ended December 31, 2019 and 2018. During the year ended December 31, 2019, proceeds from called debt securities held to maturity totaled $33.4 million, resulting in $24,000 of gross gains and no gross losses. During the year ended December 31, 2018, proceeds from calls and maturities of debt securities held to maturity totaled $5.4 million, resulting in no gross gains or losses. Debt securities held to maturity having a carrying value of $220.5 million and $236.0 million, at December 31, 2020 and December 31, 2019, respectively, were pledged as security for public funds on deposit at the Bank as required and permitted by law, pledged for outstanding borrowings at the Federal Home Loan Bank, and pledged for potential borrowings at the Federal Reserve Bank of New York. The following tables summarize the fair value and gross unrealized losses of those securities that reported an unrealized loss at December 31, 2020 and 2019 and if the unrealized loss position was continuous for the twelve months prior to those respective dates: December 31, 2020 Less Than 12 Months 12 Months or Longer Total Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) (In thousands) Mortgage-backed securities and collateralized mortgage obligations $ 2,176 $ (2) $ — $ — $ 2,176 $ (2) (5) Debt Securities Held to Maturity (continued) December 31, 2019 Less than 12 months 12 months or longer Total Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) (In thousands) U.S. government and agency obligations $ 9,934 $ (66) $ — $ — $ 9,934 $ (66) Mortgage-backed securities and collateralized mortgage obligations 27,911 (251) 772 (8) 28,683 (259) $ 37,845 $ (317) $ 772 $ (8) $ 38,617 $ (325) The Company evaluates securities for other-than-temporary impairment at each reporting period and more frequently when economic or market conditions warrant such evaluation. The temporary loss position associated with debt securities held to maturity was the result of changes in market interest rates relative to the coupon of the individual security and changes in credit spreads. The Company does not have the intent to sell securities in a temporary loss position at December 31, 2020, nor is it more likely than not that the Company will be required to sell the securities before the anticipated recovery. There were two securities in an unrealized loss position as of December 31, 2020, compared with 22 at December 31, 2019. All temporarily impaired securities were investment grade as of December 31, 2020 and 2019. The Company did not record an other-than-temporary impairment charge on debt securities held to maturity for the years ended December 31, 2020, 2019, and 2018. The Company has an equity securities portfolio which consists of stock in other financial institutions, a payment technology company, a community bank correspondent services company, and preferred stock in U.S. Government agencies which are reported at fair value on the Company's Consolidated Statements of Financial Condition. The fair value of the equities portfolio at December 31, 2020 and 2019 was $5.4 million and $2.9 million, respectively. The Company adopted ASU 2016-01 on January 1, 2019, resulting in a $548,000 after tax cumulative-effect adjustment from other comprehensive income (loss) to retained earnings, as reflected in the Consolidated Statements of Changes in Stockholders' Equity. The Company recorded a net increase in the fair value of equity securities of $767,000 and $305,000 for the years ended December 31, 2020 and 2019, respectively, as a component of non-interest income.

Loans Receivable and Allowance

Loans Receivable and Allowance for Loan Losses	12 Months Ended
	Dec. 31, 2020
Receivables [Abstract]
Loans Receivable and Allowance for Loan Losses	Loans Receivable and Allowance for Loan Losses Loans receivable at December 31, 2020 and 2019 are summarized as follows: December 31, 2020 2019 (In thousands) Real estate loans: One-to-four family $ 1,940,327 $ 2,077,079 Multifamily and commercial 2,817,965 2,919,985 Construction 328,711 298,942 Commercial business loans 752,870 483,215 Consumer loans: Home equity loans and advances 321,177 388,127 Other consumer loans 1,497 1,960 Total gross loans 6,162,547 6,169,308 Purchased credit-impaired loans 6,345 7,021 Net deferred loan costs, fees and purchased premiums and discounts 12,878 21,237 Loans receivable $ 6,181,770 $ 6,197,566 The Company had $4.1 million of SBA loans held-for-sale at December 31, 2020. The Company had no loans held-for-sale at December 31, 2019. During the year ended December 31, 2020, the Company sold $111.8 million of one-to-four family real estate loans held-for-sale, resulting in gross gains of $1.7 million and no gross losses. During the year ended December 31, 2019, the Company sold $97.4 million, $4.3 million, and $164,000 of one-to-four family real estate, fixed rate home equity loans, multifamily and commercial real estate and commercial business loans held-for-sale, respectively, resulting in gross gains of $718,000 and no gross losses. During the year ended December 31, 2018, the Company sold $3.6 million of one-to-four family real estate and fixed rate home equity loans, which resulted in no gross gains or losses. During the year ended December 31, 2020, the Company sold $15.1 million, $13.0 million, and $7.6 million of one-to-four family real estate, fixed rate home equity loans, construction loans and commercial business loans, respectively, included in loans receivable, resulting in gross gains of $161,000 and no gross losses. During the year ended December 31, 2019, the Company sold $5.3 million, $5.5 million, and $901,000 of one-to-four family real estate, fixed rate home equity loans, and multifamily and commercial real estate and commercial business loans, respectively, included in loans receivable, resulting in gross gains of $67,000 and no gross losses. During the year ended December 31, 2018, the Company sold $32.0 million of one-to-four family real estate and fixed rate home equity loans included in loans receivable, resulting in gross gains of $618,000 and no gross losses. During the year ended December 31, 2020, there were no loans purchased by the Company. During the years ended December 31, 2019 and 2018, the Company purchased $89.8 million of one-to-four family real estate loans from third parties and purchased $32.3 million of multifamily and commercial real estate loans from third parties. At December 31, 2020, commercial business loans included $344.4 million SBA PPP loans and net deferred fees related to these loans totaling $6.6 million. At December 31, 2019 there were no SBA PPP loans. At December 31, 2020 and 2019, the carrying value of loans serviced by the Company for investors was $598.0 million and $526.3 million, respectively. These loans are not included in the Consolidated Statements of Financial Condition. Servicing income totaled $1.4 million, $1.2 million, and $1.1 million for the years ended December 31, 2020, 2019 and 2018. The Company has entered into Guarantor Swaps with Freddie Mac which results in improved liquidity. During the year ended December 31, 2020, the Company exchanged $117.3 million of loans for Freddie Mac mortgage participation certificates, resulting in gross gains of $3.5 million and no gross losses. During the year ended December 31, 2019, the Company exchanged $21.6 million of loans for Freddie Mac mortgage participation certificates. During the year ended December 31, 2018, no loans were exchanged for a Freddie Mac Mortgage participation certificate. The Company retained the servicing of these loans. (7) Loans Receivable and Allowance for Loan Losses (continued) The Company has granted loans to certain officers and directors of the Company and its subsidiaries and to their associates. At December 31, 2020 and 2019, such loans totaled approximately $1.6 million and $1.1 million, respectively. During the year ended December 31, 2020, the Bank granted one new loan to a related party totaling $300,000. During the years ended December 31, 2019 and 2018, no new loans were granted to related parties. These loans are performing in accordance with their original terms. The following tables summarize the aging of loans receivable by portfolio segment, including non-accrual loans and excluding PCI loans at December 31, 2020 and 2019: December 31, 2020 30-59 Days 60-89 Days 90 Days or More Total Past Due Non-accrual Current Total (In thousands) Real estate loans: One-to-four family $ 3,068 $ 912 $ 1,901 $ 5,881 $ 2,637 $ 1,931,809 $ 1,940,327 Multifamily and commercial 15,645 — 1,238 16,883 1,873 2,799,209 2,817,965 Construction 550 — — 550 — 328,161 328,711 Commercial business loans 2,343 1,056 2,453 5,852 2,968 744,050 752,870 Consumer loans: Home equity loans and advances 1,156 696 394 2,246 678 318,253 321,177 Other consumer loans 4 — — 4 — 1,493 1,497 Total loans $ 22,766 $ 2,664 $ 5,986 31,416 $ 8,156 $ 6,122,975 $ 6,162,547 December 31, 2019 30-59 Days 60-89 Days 90 Days or More Total Past Due Non-accrual Current Total (In thousands) Real estate loans: One-to-four family $ 6,249 $ 2,132 $ 1,638 $ 10,019 $ 1,732 $ 2,065,328 $ 2,077,079 Multifamily and commercial 626 1,210 716 2,552 716 2,916,717 2,919,985 Construction — — — — — 298,942 298,942 Commercial business loans 1,056 — 2,489 3,545 3,686 475,984 483,215 Consumer loans: Home equity loans and advances 1,708 246 405 2,359 553 385,215 388,127 Other consumer loans 3 — — 3 — 1,957 1,960 Total loans $ 9,642 $ 3,588 $ 5,248 18,478 $ 6,687 $ 6,144,143 $ 6,169,308 The Company considers a loan to be delinquent when we have not received a payment within 30 days of its contractual due date. Generally, a loan is designated as a non-accrual loan when the payment of interest is 90 days or more in arrears of its contractual due date. Non-accruing loans are returned to an accrual status after there has been a sustained period of repayment performance (generally six consecutive months of payments) and both principal and interest are deemed collectible. The Company identifies loans that may need to be charged-off as a loss, by reviewing all delinquent loans, classified loans and other loans that management may have concerns about collectability. At December 31, 2020 and 2019, non-accrual loans totaled $8.2 million and $6.7 million, respectively. Included in non-accrual loans at December 31, 2020, are 19 loans totaling $2.2 million which are less than 90 days in arrears. At December 31, 2019, eight loans totaling $1.5 million, were less than 90 days in arrears. (7) Loans Receivable and Allowance for Loan Losses (continued) If non-accrual loans had performed in accordance with their original terms, interest income would have increased by $426,000, $509,000, and $126,000 for the years ended December 31, 2020, 2019 and 2018, respectively. The amount of cash basis interest income that was recognized on these loans during the years ended December 31, 2020, 2019 and 2018, was $410,000, $437,000, and $89,000, respectively. At December 31, 2020 and 2019, there were no loans past due 90 days or more still accruing interest other than COVID-19 related loan forbearance and deferrals. In accordance with the CARES Act, these loans are not included in the aging of loans receivable by portfolio segment in the table above, and the Bank continues to accrue interest income during the forbearance or deferral period. If adverse information indicating that the borrower's capability of repaying all amounts due is unlikely, the interest accrual will cease. PCI loans are loans acquired at a discount primarily due to deteriorated credit quality. These loans are initially recorded at fair value at acqisition, based upon the present value of expected future cash flows, with no related allowance for loan losses, and aggregated and accounted for as pools of loans based on common risk characteristics. The difference between the undiscounted cash flows expected at acquisition and the initial carrying amount (fair value) of the PCI loans, or the “accretable yield,” is recognized as interest income utilizing the level-yield method over the life of each pool. Contractually required payments for interest and principal that exceed the undiscounted cash flows expected at acquisition, or the “non-accretable difference,” are not recognized as a yield adjustment, as a loss accrual or a valuation allowance. Reclassifications of the non-accretable difference to the accretable yield may occur subsequent to the loan acquisition dates due to increases in expected cash flows of the loan pools. See note 3 for additional information. The following table presents information regarding the estimates of the contractually required payments, the cash flows expected to be collected, and the estimated fair value of the PCI loans acquired in the Stewardship acquisition as of November 1, 2019 (See note 3 for more details): November 1, 2019 (In thousands) Contractually required principal and interest $ 9,286 Contractual cash flows not expected to be collected (non-accretable difference) (1,823) Expected cash flows to be collected 7,463 Interest component of expected cash flows (accretable yield) (556) Fair value of acquired loans $ 6,907 The following table presents information regarding the estimates of the contractually required payments, the cash flows expected to be collected, and the estimated fair value of the PCI loans acquired in the Roselle acquisition as of April 1, 2020 (See note 3 for more details): April 1, 2020 (In thousands) Contractually required principal and interest $ 461 Contractual cash flows not expected to be collected (non-accretable difference) (237) Expected cash flows to be collected 224 Interest component of expected cash flows (accretable yield) (51) Fair value of acquired loans $ 173 (7) Loans Receivable and Allowance for Loan Losses (continued) The following table presents changes in accretable yield for PCI loans for the years ended December 31, 2020 and 2019: December 31, 2020 2019 (In thousands) Balance at beginning of period $ 511 $ — Acquisition 58 556 Accretion (34) (30) Net change in expected cash flows (117) (15) Balance at end of period $ 418 $ 511 The net increase in expected cash flows for certain pools of loans included in the table above is recognized prospectively as an adjustment to the yield over the estimated remaining life of the individual pools. We may obtain physical possession of real estate collateralizing a residential mortgage loan via foreclosure or through an in-substance repossession. At December 31, 2020 and 2019, the Company had no real estate owned. At of December 31, 2020 and 2019, we had two and four residential mortgage loans with carrying values totaling $398,000 and $522,000, respectively, collateralized by residential real estate which are in the process of foreclosure. The states of New Jersey, New York and Pennsylvania have issued executive orders which declare moratoriums on removing individuals from a residential property until at least two months after the COVID health crisis has ended. In response to these orders, in March 2020, the Company temporarily suspended residential property foreclosure sales and evictions. The Company maintains the allowance for loan losses through provisions for loan losses which are charged to income. Charge-offs against the allowance for loan losses are taken on loans where management determines that the collection of loan principal is unlikely. Recoveries made on loans that have been charged-off are credited to the allowance for loan losses. As part of the evaluation of the adequacy of the allowance for loan losses, management prepares an analysis each quarter that categorizes the entire loan portfolio by certain risk characteristics such as loan type (residential mortgage, commercial mortgage, construction, commercial business, etc.) and loan risk rating. The Company utilizes an eight-point risk rating system to summarize its loan portfolio into categories with similar risk characteristics. Loans deemed to be “acceptable quality” are rated 1 through 4 (Pass), with a rating of 1 established for loans with minimal risk. Loans that are deemed to be of “questionable quality” are rated 5 (Special Mention) or 6 (Substandard). Loans with adverse classifications are rated 7 (Doubtful) or 8 (Loss). The risk ratings are also confirmed through periodic loan review examinations, which are currently performed by both an independent third-party and the Company's credit risk review department. The Company requires an annual review be performed above certain dollar thresholds, depending on loan type, to help determine the appropriate risk ratings. Results from examinations are presented to the Audit Committee of the Board of Directors. Management estimates the allowance for loans collectively evaluated for impairment by applying quantitative loss factors to the loan segments by risk rating and determining adjustments to each loan segment at an overall level. Quantitative loss factors give consideration to historical loss experience and migration experience by loan type based on an appropriate look-back period, adjusted for a loss emergence period. Qualitative adjustments give consideration to other qualitative or environmental factors such as trends and levels of delinquencies, impaired loans, charge-offs, recoveries and loan volumes, as well as national and local economic trends and conditions. Qualitative adjustments reflect risks in the loan portfolio not captured by the quantitative loss factors and, as such, are evaluated relative to the risk levels present over the look-back period. The reserves resulting from the application of both the quantitative experience and qualitative factors are combined to arrive at the allowance for loan losses for loans collectively evaluated for impairment. Management believes the primary risks inherent in the portfolio are a general decline in the economy, a decline in real estate market values, rising unemployment, increasing vacancy rates, and increases in interest rates in the absence of economic improvement. Any one or a combination of these events may adversely affect a borrowers’ ability to repay its loan, resulting in increased delinquencies and loan losses. Accordingly, the Company has recorded loan losses at a level which is estimated to represent the current risk in its loan portfolio. Management considers it important to maintain the ratio of the allowance for loan losses to total loans at an acceptable level considering the current composition of the loan portfolio. (7) Loans Receivable and Allowance for Loan Losses (continued) Although management believes that the Company has established and maintains the allowance for loan losses at appropriate levels, additional reserves may be necessary if future economic and other conditions differ substantially from the current operating environment. Management evaluates its estimates and assumptions on an ongoing basis and the estimates and assumptions are adjusted when facts and circumstances necessitate a re-valuation of the estimate. As future events and their effects cannot be determined with precision, actual results could differ significantly from these estimates. In addition, regulatory agencies periodically review the adequacy of the Company’s allowance for loan losses as an integral part of their examination process. Such agencies may require the Company to recognize additions to the allowance or additional write-downs based on their judgments about information available to them at the time of their examination. Although management uses the best information available, the level of the allowance for loan losses remains an estimate that is subject to significant judgement The Bank defines a loan as impaired when, based on current information and events, it is probable that a creditor will be unable to collect all amounts due under the contractual terms of the loan agreement. All multifamily and commercial real estate, construction, and commercial business loans with an outstanding balance of greater than $500,000 and not accruing interest, loans modified in a troubled debt restructuring (TDR), and other loans if there is specific information of a collateral shortfall are individually evaluated for impairment. Impairment is measured by determining the present value of expected future cash flows or, for collateral-dependent loans, the fair value of the collateral less estimated selling costs. The following tables summarize loans receivable (including PCI loans) and allowance for loan losses by portfolio segment and impairment method at December 31, 2020 and 2019: December 31, 2020 One-to-Four Family Multifamily and Commercial Construction Commercial Business Home Equity Loans and Advances Other Consumer Loans Total (In thousands) Allowance for loan losses: Individually evaluated for impairment $ 391 $ 601 $ — $ 84 $ 12 $ — $ 1,088 Collectively evaluated for impairment 13,195 30,080 11,271 17,300 1,736 6 73,588 Loans acquired with deteriorated credit quality — — — — — — — Total $ 13,586 $ 30,681 $ 11,271 $ 17,384 $ 1,748 $ 6 $ 74,676 Total loans: Individually evaluated for impairment $ 7,257 $ 32,792 $ — $ 3,447 $ 1,651 $ — $ 45,147 Collectively evaluated for impairment 1,933,070 2,785,173 328,711 749,423 319,526 1,497 6,117,400 Loans acquired with deteriorated credit quality 309 4,893 — 1,143 — — 6,345 Total loans $ 1,940,636 $ 2,822,858 $ 328,711 $ 754,013 $ 321,177 $ 1,497 $ 6,168,892 (7) Loans Receivable and Allowance for Loan Losses (continued) December 31, 2019 One-to-Four Family Multifamily and Commercial Construction Commercial Business Home Equity Loans and Advances Other Consumer Loans Total (In thousands) Allowance for loan losses: Individually evaluated for impairment $ 484 $ 2 $ — $ 1,121 $ 14 $ — $ 1,621 Collectively evaluated for impairment 13,296 22,978 7,435 14,715 1,655 9 60,088 Loans acquired with deteriorated credit quality — — — — — — — Total $ 13,780 $ 22,980 $ 7,435 $ 15,836 $ 1,669 $ 9 $ 61,709 Total loans: Individually evaluated for impairment $ 8,891 $ 2,599 $ — $ 5,178 $ 2,143 $ — $ 18,811 Collectively evaluated for impairment 2,068,188 2,917,386 298,942 478,037 385,984 1,960 6,150,497 Loans acquired with deteriorated credit quality 429 4,866 — 1,726 — — 7,021 Total loans $ 2,077,508 $ 2,924,851 $ 298,942 $ 484,941 $ 388,127 $ 1,960 $ 6,176,329 Loan modifications to borrowers experiencing financial difficulties that are considered troubled debt restructurings ("TDRs") primarily involve the lowering of the monthly payments on such loans through either a reduction in interest rate below a market rate, an extension of the term of the loan without a corresponding adjustment to the risk premium reflected in the interest rate, or a combination of these two methods. These modifications generally do not result in the forgiveness of principal or accrued interest. In addition, the Company attempts to obtain additional collateral or guarantor support when modifying such loans. Non-accruing restructured loans may be returned to accrual status when there has been a sustained period of repayment performance (generally six consecutive months of payments) and both principal and interest are deemed collectible. Section 4013 of the CARES Act, “Temporary Relief from Troubled Debt Restructurings,” allows banks to temporarily suspend certain requirements under GAAP related to TDRs for a limited period of time to account for the effects of COVID-19. The Bank elected to account for modifications on certain loans under Section 4013 of the CARES Act or, if the loan modification was not eligible under Section 4013, used the criteria in the COVID-19 guidance to determine when the loan modification was not a TDR in accordance with ASC 310-40. Guidance noted that modification or deferral programs mandated by the federal or a state government related to COVID-19 would not be in the scope of ASC 310-40, such as a state program that requires all institutions within that state to suspend mortgage payments for a specified period. These short-term loan modifications will not be treated as troubled debt restructurings during the short-term modification period if the loan was not in arrears at December 31, 2019. Furthermore, based on current evaluations, generally, we have continued the accrual of interest on these loans during the short-term modification period. The Consolidated Appropriations Act, 2021, which was enacted in late December 2020, extended certain provisions of the CARES Act, including provisions permitting loan deferral extension requests to not be treated as troubled debt restructurings. The following tables present the number of loans modified as TDRs during the years ended December 31, 2020, 2019 and 2018, along with their balances immediately prior to the modification date and post-modification. Post-modification recorded investment represents the net book balance immediately following modification. (7) Loans Receivable and Allowance for Loan Losses (continued) For the Years Ended December 31, 2020 2019 No. of Loans Pre-modification Recorded Investment Post-modification Recorded Investment No. of Loans Pre-modification Recorded Investment Post-modification Recorded Investment (Dollars in thousands) Troubled Debt Restructurings Real estate loans: Multifamily and commercial 5 $ 17,022 $ 17,022 — $ — $ — Commercial business loans 2 11,507 12,802 1 4,095 4,095 Total restructured loans 7 $ 28,529 $ 29,824 1 $ 4,095 $ 4,095 For the Year Ended December 31, 2018 No. of Loans Pre-modification Recorded Investment Post-modification Recorded Investment (Dollars in thousands) Troubled Debt Restructurings Real estate loans: One-to-four family 5 $ 801 $ 801 Multifamily and commercial 1 65 65 Consumer loans: Home equity loans and advances 1 588 588 Total restructured loans 7 $ 1,454 $ 1,454 The activity in the allowance for loan losses for the years ended December 31, 2020, 2019 and 2018, are as follows: Years Ended December 31, 2020 2019 2018 (In thousands) Balance at beginning of period $ 61,709 $ 62,342 $ 58,178 Provision charged 18,447 4,224 6,677 Recoveries 823 496 707 Charge-offs (6,303) (5,353) (3,220) Balance at end of period $ 74,676 $ 61,709 $ 62,342 (7) Loans Receivable and Allowance for Loan Losses (continued) The activity in the allowance for loan losses by portfolio segment for the years ended December 31, 2020, 2019 and 2018, are as follows: For the Year Ended December 31, 2020 One-to-Four Family Multifamily and Commercial Construction Commercial Business Home Equity Loans and Advances Other Consumer Loans Total (In thousands) Balance at beginning of period $ 13,780 $ 22,980 $ 7,435 $ 15,836 $ 1,669 $ 9 $ 61,709 Provision charged (credited) 1,299 7,713 3,835 5,360 239 1 18,447 Recoveries 438 16 1 308 60 — 823 Charge-offs (1,931) (28) — (4,120) (220) (4) (6,303) Balance at end of period $ 13,586 $ 30,681 $ 11,271 $ 17,384 $ 1,748 $ 6 $ 74,676 For the Year Ended December 31, 2019 One-to-Four Family Multifamily and Commercial Construction Commercial Business Home Equity Loans and Advances Other Consumer Loans Total (In thousands) Balance at beginning of period $ 15,232 $ 23,251 $ 7,217 $ 14,176 $ 2,458 $ 8 $ 62,342 Provision charged (credited) (429) (178) 216 5,250 (638) 3 4,224 Recoveries 30 10 2 404 50 — 496 Charge-offs (1,053) (103) — (3,994) (201) (2) (5,353) Balance at end of period $ 13,780 $ 22,980 $ 7,435 $ 15,836 $ 1,669 $ 9 $ 61,709 For the Year Ended December 31, 2018 One-to-Four Family Multifamily and Commercial Construction Commercial Business Home Equity Loans and Advances Other Consumer Loans Unallocated Total (In thousands) Balance at beginning of period $ 19,991 $ 19,933 $ 5,217 $ 8,275 $ 4,576 $ 8 $ 178 $ 58,178 Provision charged (credited) (4,503) 3,445 1,997 7,860 (1,949) 5 (178) 6,677 Recoveries 334 2 3 240 122 6 — 707 Charge-offs (590) (129) — (2,199) (291) (11) — (3,220) Balance at end of period $ 15,232 $ 23,251 $ 7,217 $ 14,176 $ 2,458 $ 8 $ — $ 62,342 (7) Loans Receivable and Allowance for Loan Losses (continued) The following tables present loans individually evaluated for impairment by loan segment, excluding PCI loans, at December 31, 2020 and 2019: At December 31, 2020 Recorded Investment Unpaid Principal Balance Specific Allowance (In thousands) With no allowance recorded: Real estate loans: One-to-four family $ 3,344 $ 3,898 $ — Multifamily and commercial 13,058 13,094 — Commercial business loans 1,945 1,945 — Consumer loans: Home equity loans and advances 714 851 — 19,061 19,788 — With a specific allowance recorded: Real estate loans: One-to-four family 3,913 3,919 391 Multifamily and commercial 19,734 20,350 601 Commercial business loans 1,502 1,502 84 Consumer loans: Home equity loans and advances 937 937 12 26,086 26,708 1,088 Total: Real estate loans: One-to-four family 7,257 7,817 391 Multifamily and commercial 32,792 33,444 601 Commercial business loans 3,447 3,447 84 Consumer loans: Home equity loans and advances 1,651 1,788 12 Total loans $ 45,147 $ 46,496 $ 1,088 (7) Loans Receivable and Allowance for Loan Losses (continued) At December 31, 2019 Recorded Investment Unpaid Principal Balance Specific Allowance (In thousands) With no allowance recorded: Real estate loans: One-to-four family $ 4,314 $ 5,473 $ — Multifamily and commercial 1,494 2,191 — Commercial business loans 3,859 4,048 — Consumer loans: Home equity loans and advances 1,080 1,217 — 10,747 12,929 — With a specific allowance recorded: Real estate loans: One-to-four family 4,577 4,613 484 Multifamily and commercial 1,105 1,105 2 Commercial business loans 1,319 4,307 1,121 Consumer loans: Home equity loans and advances 1,063 1,063 14 8,064 11,088 1,621 Total: Real estate loans: One-to-four family 8,891 10,086 484 Multifamily and commercial 2,599 3,296 2 Commercial business loans 5,178 8,355 1,121 Consumer loans: Home equity loans and advances 2,143 2,280 14 Total loans $ 18,811 $ 24,017 $ 1,621 Specific allocations of the allowance for loan losses attributable to impaired loans totaled $1.1 million and $1.6 million at December 31, 2020 and 2019, respectively. At December 31, 2020 and 2019, impaired loans for which there was no related allowance for loan losses totaled $19.1 million and $10.7 million, respectively. (7) Loans Receivable and Allowance for Loan Losses (continued) The following table presents interest income recognized for loans individually evaluated for impairment, by loan segment, excluding PCI loans for the years ended December 31, 2020, 2019 and 2018: For the Years Ended December 31, 2020 2019 2018 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized (In thousands) Real estate loans: One-to-four family $ 7,946 $ 305 $ 8,811 $ 434 $ 10,224 $ 445 Multifamily and commercial 23,701 1,091 2,639 147 2,712 155 Construction — — 850 — — — Commercial business loans 4,963 216 6,378 479 3,060 118 Consumer loans: Home equity loans and advances 1,909 100 2,562 143 3,361 173 Totals $ 38,519 $ 1,712 $ 21,240 $ 1,203 $ 19,357 $ 891 The recorded investment in TDRs totaled $45.4 million at December 31, 2020, of which one loan totaling $91,000 was over 90 days past due, and three loans totaling $11.9 million were 30-59 days past due. The remaining loans modified were current at the time of restructuring and have complied with the terms of their restructure agreement at December 31, 2020. The recorded investment in TDRs totaled $20.0 million at December 31, 2019, of which there were no loans were over 90 days past due and three loans totaling $660,000 were 30-59 days past due. The remaining loans modified were current at the time of restructuring and have complied with the terms of their restructure agreement at December 31, 2019. The recorded investment in TDRs totaled $16.0 million at December 31, 2018, of which one loan totaling $101,000 was over 90 days past due, and seven loans totaling $1.0 million were 30-59 days past due. The remaining loans modified were current at the time of restructuring and have complied with the terms of their restructure agreement at December 31, 2018. The following tables present loans receivable by credit quality risk indicator and by loan segment, excluding PCI loans at December 31, 2020 and 2019: December 31, 2020 One-to-Four Family Multifamily and Commercial Construction Commercial Business Home Equity Loans and Advances Other Consumer Loans Total (In thousands) Pass $ 1,935,032 $ 2,758,905 $ 328,711 $ 740,010 $ 320,092 $ 1,497 $ 6,084,247 Special mention 404 40,392 — 6,718 — — 47,514 Substandard 4,891 18,668 — 6,142 1,085 — 30,786 Doubtful — — — — — — — Total $ 1,940,327 $ 2,817,965 $ 328,711 $ 752,870 $ 321,177 $ 1,497 $ 6,162,547 (7) Loans Receivable and Allowance for Loan Losses (continued) December 31, 2019 One-to-Four Family Multifamily and Commercial Construction Commercial Business Home Equity Loans and Advances Other Consumer Loans Total (In thousands) Pass $ 2,072,878 $ 2,900,286 $ 298,942 $ 454,183 $ 387,251 $ 1,960 $ 6,115,500 Special mention 419 4,724 — 20,170 — — 25,313 Substandard 3,782 14,975 — 8,862 876 — 28,495 Doubtful — — — — — — — Total $ 2,077,079 $ 2,919,985 $ 298,942 $ 483,215 $ 388,127 $ 1,960 $ 6,169,308

Office Properties and Equipment

Office Properties and Equipment, net	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Office Properties and Equipment, net	Office Properties and Equipment, net Office properties and equipment less accumulated depreciation at December 31, 2020 and 2019 are summarized as follows: December 31, 2020 2019 (In thousands) Land $ 10,174 $ 11,069 Buildings 31,523 27,340 Land and building improvements 35,307 31,520 Leasehold improvements 22,166 24,038 Furniture and equipment 33,971 36,828 133,141 130,795 Less accumulated depreciation and amortization 57,167 57,828 Total office properties and equipment, net $ 75,974 $ 72,967 Land and building improvements at December 31, 2020 and 2019 included $2.6 million and $1.3 million, respectively, in construction in progress for the renovation of the Bank's corporate headquarters and various other facilities. At December 31, 2020 and 2019, $1.9 million and $1.8 million, respectively, included in buildings, are properties classified as held-for-sale, and carried at fair value.

Leases

Leases	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Leases	Leases Effective January 1, 2020, the Company adopted ASU 2016-02 Leases (Topic 842) and all subsequent ASU's that modified Topic 842, as explained in note 2, Summary of Significant Accounting Policies, Accounting Pronouncements Adopted . The Company's leases primarily relate to real estate property for branches and office space. At December 31, 2020, all of the Company's leases are classified as operating leases. (9) Leases (continued) The Company determines if an arrangement is a lease at inception. Topic 842 requires lessees to recognize a right-of-use asset and a lease liability, measured at the present value of the future minimum lease payments, at the lease commencement date. At the time of adoption, an operating lease right-of-use asset of $22.2 million and operating lease liabilities of $23.3 million were recorded in other assets other liabilities At December 31, 2020, the weighted average remaining lease term for operating leases was 7.5 years and the weighted average discount rate used in the measurement of operating lease liabilities was 2.26% . The Company elected to account for the lease and non-lease components separately since such amounts are readily determinable under the Company's lease contracts. Operating lease expense is recognized on a straight-line basis over the lease term, while variable lease payments are recognized as incurred. Variable lease payments include common area maintenance charges, real estate taxes, repairs and maintenance costs and utilities. Operating and variable lease expenses are recorded in occupancy expense in the Consolidated Statements of Income. During the year ended December 31, 2020, operating and variable lease expenses totaled approximately $2.4 million. There were no sale and leaseback transactions, leveraged leases or lease transactions with related parties during the year ended December 31, 2020. At December 31, 2020, the Company had no leases that had not yet commenced. The following table summarizes lease payment obligations for each of the next five years and thereafter as follows: At December 31, 2020 Lease Payment Obligations (In thousands) 2021 $ 4,010 2022 3,624 2023 3,310 2024 2,586 2025 1,914 Thereafter 6,620 Total undiscounted cash flows 22,064 Discount on cash flows (1,992) Total lease liability $ 20,072 At December 31, 2019, operating lease commitments under lessee arrangements were $4.9 million, $4.5 million, $4.0 million, $3.5 million and $2.7 million for 2020 through 2024, respectively, and $5.0 million in aggregate for all years thereafter.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets Intangible assets at December 31, 2020 and 2019 are summarized as follows: December 31, 2020 2019 (In thousands) Goodwill $ 80,285 $ 60,763 Core deposit intangibles 6,197 7,245 Mortgage servicing rights 902 574 $ 87,384 $ 68,582 Mortgage servicing rights' amortization expense for the years ended December 31, 2020, 2019, and 2018 amounted to $128,000, $109,000, and $73,000, respectively. Core deposit intangible amortization expense for the years ended December 31, 2020 and 2019 amounted to $1.0 million and $222,000, respectively. There was no core deposit amortization expense for the year ended December 31, 2018. Scheduled amortization of core deposit intangibles for each of the next five years and thereafter is as follows: Year Ending December 31, Core Deposit Intangible Amortization (In thousands) 2021 $ 1,024 2022 961 2023 892 2024 819 2025 737 Thereafter 1,764 Total $ 6,197

Deposits

Deposits	12 Months Ended
	Dec. 31, 2020
Deposits [Abstract]
Deposits	Deposits Deposits at December 31, 2020 and 2019 are summarized as follows: December 31, 2020 2019 Balance Weighted Average Rate Balance Weighted Average Rate (Dollars in thousands) Non-interest-bearing demand $ 1,354,605 — % $ 958,442 — % Interest-bearing demand 2,189,164 0.40 1,720,383 1.03 Money market accounts 588,180 0.36 410,392 0.91 Savings and club deposits 688,309 0.16 543,480 0.15 Certificates of deposit 1,958,366 1.44 2,013,145 2.25 Total deposits $ 6,778,624 0.59 % $ 5,645,842 1.20 % Included in the above balances at December 31, 2020 and 2019 are certificates of deposit obtained through brokers, totaling $26.3 million and $31.6 million that were acquired from Stewardship. The aggregate amount of certificates of deposit that meet or exceed $100,000 totaled approximately $1.0 billion and $1.1 billion at December 31, 2020 and 2019, respectively. Scheduled maturities of certificates of deposit accounts at December 31, 2020 and 2019 are summarized as follows: December 31, 2020 2019 (In thousands) One year or less $ 1,494,129 $ 1,293,613 After one year to two years 337,579 548,995 After two years to three years 52,809 142,458 After three years to four years 23,018 11,362 After four years 50,831 16,717 $ 1,958,366 $ 2,013,145 Interest expense on deposits for the years ended December 31, 2020, 2019, and 2018 are summarized as follows: Years Ended December 31, 2020 2019 2018 (In thousands) Demand (including money market accounts) $ 15,556 $ 19,922 $ 12,933 Savings and club deposits 1,023 770 993 Certificates of deposit 38,667 40,859 25,597 $ 55,246 $ 61,551 $ 39,523

Borrowings

Borrowings	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Borrowings	Borrowings Borrowings at December 31, 2020 and 2019 are summarized as follows: December 31, 2020 2019 2020 2019 Balance Weighted Average Interest Rate (In thousands) Overnight lines of credit $ — $ 107,800 — % 1.81 % FHLB advances 792,412 1,275,391 1.18 2.09 Subordinated notes — 16,899 — 6.75 Junior subordinated debentures 6,952 6,932 3.20 5.09 $ 799,364 $ 1,407,022 1.20 % 2.14 % At December 31, 2020, the Company had no outstanding overnight lines of credit with the FHLB. At December 31, 2019, the Company had $107.8 million of outstanding lines of credit with the FHLB. Interest expense on the overnight advances for the years ended December 31, 2020, 2019, and 2018, were $425,000, $1.8 million, and $2.2 million, respectively. At December 31, 2020, the Bank could borrow funds from the FHLB under an overnight advance program up to the Bank's maximum borrowing capacity based on its ability to collateralize such borrowings. Members in good standing can borrow up to 50% of their asset size as long as they have qualifying collateral to support the advance and purchase of FHLB capital. Additionally, at both December 31, 2020 and 2019, the Bank had unused correspondent bank lines of credit with an aggregate overnight borrowing capacity of $250.0 million. At December 31, 2020, FHLB advances were at fixed rates with maturities between January 2021 and February 2025, and at December 31, 2019, FHLB advances were at fixed rates with maturities between January 2020 and August 2024. At December 31, 2020 and 2019, FHLB advances were collateralized by FHLB capital stock owned by the Bank, and loans with carrying values totaling $2.1 billion and $1.9 billion, respectively. Loans securing advances consists of one-to-four family, multifamily and commercial and home equity real estate loans. At December 31, 2020 and 2019, FHLB advances were also collateralized by securities with carrying values totaling $222.4 million and $246.2 million, respectively. Interest expense on fixed rate FHLB advances for the years ended December 31, 2020, 2019, and 2018, were $17.7 million, $25.2 million, and $17.1 million, respectively. At December 31, 2020 and 2019, short-term FHLB advances totaling $430.0 million and $410.0 million, respectively, were designated as hedged items as part of a cash flow hedging program. See note 22 for information regarding these transactions. Scheduled maturities of FHLB advances at December 31, 2020 are summarized as follows: Year Ended December 31, 2020 (In thousands) One year or less $ 496,042 After one year to two years 179,706 After two years to three years 40,391 After three years to four years 51,273 After four years 25,000 Total FHLB advances $ 792,412 (12) Borrowings (continued) At December 31, 2020 and 2019, the carrying value of junior subordinated debt balances were $7.0 million and $6.9 million, respectively. The balance outstanding at December 31, 2020 and 2019 represents debentures issued in 2003 by Stewardship Statutory Trust (the "Trust"), a statutory business trust that was acquired in the Stewardship merger. These floating rate debentures mature on September 17, 2033 and adjust quarterly at a rate of three month LIBOR plus 3.20%. At December 31, 2020 and 2019 the rate of interest was 3.20% and 5.09%, respectively. In August 2018, the Company redeemed all other junior subordinated debt securities that were previously outstanding. Interest expense for the years ended December 31, 2020, 2019, and 2018 were $295,000, $65,000, $3.5 million, respectively.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Stockholders' Equity	Stockholders' Equity Regulatory Capital The Company and its subsidiary Bank are subject to various regulatory capital requirements administered by the federal banking regulators, including a risk-based capital measure. The Federal Reserve establishes capital requirements, including well capitalized standards, for the consolidated financial holding company, and the Office of the Comptroller of the Currency (the "OCC") has similar requirements for the Company's subsidiary bank. Failure to meet minimum capital requirements can initiate certain mandatory and possibly additional discretionary actions by regulators that, if undertaken, could have a direct material effect on the Company's Consolidated Statements of Financial Condition. Federal regulators require federally insured depository institutions to meet several minimum capital standards: (1) total capital to risk-weighted assets of 8.0%; (2) tier 1 capital to risk-weighted assets of 6.0%; (3) common equity tier 1 capital to risk-weighted assets of 4.5%; and (4) tier 1 capital to adjusted total assets of 4.0%. In addition to establishing the minimum regulatory capital requirements, the regulations limit capital distributions and certain discretionary bonus payments to management if the institution does not hold a "capital conservation buffer" consisting of 2.5% of common equity tier 1 capital to risk-weighted assets above the amount necessary to meet its minimum risk-based capital requirements. The capital conservation buffer capital requirement was fully phased on January 1, 2019. The regulators established a framework for the classification of savings institutions into five categories: well capitalized, adequately capitalized, undercapitalized, significantly undercapitalized, and critically undercapitalized. Generally, an institution is considered well capitalized if it has: a total capital to risk-weighted assets ratio of at least 10.0%, a tier 1 capital to risk-weighted assets ratio of at least 8.0%, a common tier 1 capital to risk-weighted assets ratio of at least 6.5%, and a tier 1 capital to adjusted total assets ratio of at least 5.0%. As of December 31, 2020 and 2019, each of the Company and the Bank exceeded all capital adequacy requirements to which it is subject. Based upon most recent notification from federal banking regulators, the Bank was categorized as well capitalized as of June 30, 2020, under the regulatory framework for prompt corrective action. There are no conditions existing or events which have occurred since notification that management believes have changed the Bank's category. The following table presents the Company's and the Bank's actual capital amounts and ratios at December 31, 2020 and 2019 compared to the Federal Reserve Bank minimum capital adequacy requirements and the Federal Reserve Bank requirements for classification as a well-capitalized institution: (13) Stockholders' Equity (continued) Regulatory Capital (continued) Actual Minimum Capital Adequacy Requirements Minimum Capital Adequacy Requirements With Capital Conservation Buffer To Be Well Capitalized Under Prompt Corrective Action Provisions Amount Ratio Amount Ratio Amount Ratio Amount Ratio Company (In thousands, except ratio data) At December 31, 2020: Total capital (to risk-weighted assets) $ 1,070,361 18.54 % $ 461,766 8.00 % $ 606,068 10.50 % N/A N/A Tier 1 capital (to risk-weighted assets) 998,172 17.29 346,325 6.00 490,627 8.50 N/A N/A Common equity tier 1 capital (to risk-weighted assets) 990,955 17.17 259,744 4.50 404,046 7.00 N/A N/A Tier 1 capital (to adjusted total assets) 998,172 11.38 350,923 4.00 350,923 4.00 N/A N/A At December 31, 2019: Total capital (to risk-weighted assets) $ 1,061,555 17.25 % $ 492,438 8.00 % $ 646,324 10.50 % N/A N/A Tier 1 capital (to risk-weighted assets) 988,172 16.05 369,328 6.00 523,215 8.50 N/A N/A Common equity tier 1 capital (to risk-weighted assets) 980,995 15.94 276,996 4.50 430,883 7.00 N/A N/A Tier 1 capital (to adjusted total assets) 988,172 12.92 305,824 4.00 305,824 4.00 N/A N/A Bank At December 31, 2020: Total capital (to risk-weighted assets) $ 924,959 16.05 % $ 460,944 8.00 % $ 604,989 10.50 % $ 576,180 10.00 % Tier 1 capital (to risk-weighted assets) 852,897 14.80 345,708 6.00 489,753 8.50 460,944 8.00 Common equity tier 1 capital (to risk-weighted assets) 852,897 14.80 259,281 4.50 403,326 7.00 374,517 6.50 Tier 1 capital (to adjusted total assets) 852,897 9.72 350,815 4.00 350,815 4.00 438,519 5.00 At December 31, 2019: Total capital (to risk-weighted assets) $ 844,664 14.25 % $ 474,125 8.00 % $ 622,290 10.50 % $ 592,657 10.00 % Tier 1 capital (to risk-weighted assets) 782,881 13.21 355,594 6.00 503,758 8.50 474,125 8.00 Common equity tier 1 capital (to risk-weighted assets) 782,881 13.21 266,696 4.50 414,860 7.00 385,227 6.50 Tier 1 capital (to adjusted total assets) 782,881 10.25 305,423 4.00 305,423 4.00 381,779 5.00 (13) Stockholders' Equity (continued) Stock Repurchase Program On June 11, 2019, the Company announced that its Board of Directors authorized the Company's first stock repurchase program since the completion of its minority public offering in April 2018. This program, which commenced on June 13, 2019, authorized the purchase of up to 4,000,000 shares, or approximately 3.5%, of the Company's then issued and outstanding common stock. On December 5, 2019, the Company announced that the Board of Directors had expanded its stock repurchase program to authorize the purchase of an additional 3,000,000 shares of the Company's outstanding common stock in addition to the shares remaining under the repurchase program announced on June 11, 2019. On April 23, 2020, the Company completed the repurchases under these stock repurchase programs. On September 10, 2020, the Company announced that its Board of Directors authorized the Company's second stock repurchase program for the purchase of up to 5,000,000 shares, or approximately 4.3%, of the Company's issued and outstanding common stock, commencing on September 15, 2020. During the years ended December 31, 2020 and 2019, the Company repurchased 7,587,142 shares at at cost of approximately $108.2 million, or $14.26 per share, and 3,543,800 shares at a cost of approximately $55.3 million, or $15.61 per share, respectively, under these programs. Repurchased shares are held as treasury stock and are available for general corporate purposes. There were no stock repurchase programs in effect at or during the year ended December 31, 2018.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
Employee Benefit Plans	Employee Benefit Plans Pension Plan, Retirement Income Maintenance Plan (the "RIM Plan"), Post-retirement Plan, Split-Dollar Life Insurance Plans The Company maintains a single employer, tax-qualified defined benefit pension plan (the "Pension Plan") which covers full-time employees that satisfy the Pension Plan's eligibility requirements. The benefits are based on years of service and the employee's average compensation for the highest five consecutive years of employment. Effective October 1, 2018, employees hired by the Bank are not eligible to participate in the Bank's Pension Plan as the plan has been closed to new employees as of that date. The Company's policy is to fund at least the minimum contribution required by the Employee Retirement Income Security Act of 1974. GAAP requires an employer to: (a) recognize in its statement of financial position the over-funded or under-funded status of a defined benefit post-retirement plan measured as the difference between the fair value of plan assets and the benefit obligation; (b) measure a plan’s assets and its obligations that determine its funded status at the end of the employer’s fiscal year (with limited exceptions); and (c) recognize as a component of other comprehensive income (loss), net of tax, the actuarial gains and losses and the prior service costs and credits that arise during the period. The assets of the plan are primarily invested in fixed income and equity funds. The Company also has a Retirement Income Maintenance Plan (the "RIM" Plan), which is a non-qualified defined benefit plan which provides benefits to all employees of the Company if their benefits under the Pension Plan are limited by Internal Revenue Code 415 and 401(a)(17). In addition, the Company provides certain health care and life insurance benefits to eligible retired employees under a Post-retirement Plan. The Company accrues the cost of retiree health care and other benefits during the employees’ period of active service. Effective January 1, 2019, the Post-retirement Plan has also been closed to new hires. The Company also provides life insurance benefits to eligible employees under an endorsement split-dollar life insurance program. The Company also provides life insurance benefits to eligible employees under an endorsement split-dollar life insurance program. The Company recognizes a liability for future benefits applicable to endorsement split-dollar life insurance arrangements that provide death benefits post-retirement. Through the mergers with Stewardship and Roselle, the Company recognized an additional liability for future benefits applicable to endorsement split-dollar life insurance arrangements that provide death benefits post-retirement under those respective Bank's program. The following table sets forth information regarding the Pension, RIM, Post-retirement and Split-Dollar Life Insurance Plans at December 31, 2020 and 2019: (14) Employee Benefit Plans (continued) Pension Plan, Retirement Income Maintenance Plan (the "RIM Plan") Post-retirement Plan, Split-Dollar Life Insurance Plans (cont'd) December 31, 2020 2019 2020 2019 2020 2019 2020 2019 Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance (In thousands) Change in benefit obligation: Benefit obligation at beginning of year $ 263,826 $ 209,205 $ 13,696 $ 11,285 $ 24,603 $ 20,964 $ 14,100 $ 10,462 Acquired — — — — — — 1,981 310 Service cost 7,985 6,494 267 210 394 339 467 354 Interest cost 7,608 8,569 405 466 683 826 507 457 Actuarial (gain) loss 40,281 46,001 2,506 2,074 5,506 3,141 3,137 2,649 Benefits paid (7,260) (6,443) (344) (339) (565) (667) (211) (132) Benefit obligation at end of year 312,440 263,826 16,530 13,696 30,621 24,603 19,981 14,100 Change in plan assets: Fair value of plan assets at beginning of year 356,347 272,974 — — — — — — Actuarial return on plan assets 50,820 54,816 — — — — — — Employer contributions 12,000 35,000 344 339 565 667 211 132 Benefits paid (7,260) (6,443) (344) (339) (565) (667) (211) (132) Fair value of plan assets at end of year 411,907 356,347 — — — — — — Funded status at end of year $ 99,467 $ 92,521 $ (16,530) $ (13,696) $ (30,621) $ (24,603) $ (19,981) $ (14,100) At December 31, 2020 and 2019, the unfunded liability for the RIM Plan and Post-retirement Plan of $16.5 million and $30.6 million, and $13.7 million and $24.6 million, respectively, were included in other liabilities in the Consolidated Statements of Financial Condition, and the over-funded pension benefits associated with the Pension Plan totaling $99.5 million and $92.5 million respectively, were included in other assets in the Consolidated Statements of Financial Condition. The components of accumulated other comprehensive income related to the Pension Plan, RIM Plan, and Post-retirement Plan on a pre-tax basis, at December 31, 2020, 2019, and $2018, are summarized in the following table: At December 31, 2020 2019 Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance (In thousands) Unrecognized prior service costs $ — $ — $ — $ 405 $ — $ — $ — $ 461 Unrecognized net actuarial income 76,686 7,686 12,417 8,741 68,752 5,777 7,221 6,058 Total accumulated other comprehensive income $ 76,686 $ 7,686 $ 12,417 $ 9,146 $ 68,752 $ 5,777 $ 7,221 $ 6,519 (14) Employee Benefit Plans (continued) Pension Plan, Retirement Income Maintenance Plan (the "RIM Plan") Post-retirement Plan, Split-Dollar Life Insurance Plans (cont'd) At December 31 2018 Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance (In thousands) Unrecognized prior service costs $ — $ — $ — $ 517 Unrecognized net actuarial income 59,579 3,748 4,226 3,658 Total accumulated other comprehensive income $ 59,579 $ 3,748 $ 4,226 $ 4,175 Net periodic benefit (income) cost for the Pension Plan, RIM Plan, Post-retirement Plan and Split-dollar Life Insurance plan benefits for the years ended December 31, 2020 and 2019, and 2018, includes the following components: For the Year Ended December 31, 2020 Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance Affected Line Item in the Consolidated Statements of Income (In thousands) Service cost $ 7,985 $ 267 $ 394 $ 467 Compensation and employee benefits Interest cost 7,608 405 683 507 Other non-interest expense Expected return on plan assets (23,375) — — — Other non-interest expense Amortization: Prior service cost — — — 56 Other non-interest expense Net loss 4,902 397 309 454 Other non-interest expense Net periodic (income) benefit cost $ (2,880) $ 1,069 $ 1,386 $ 1,484 (14) Employee Benefit Plans (continued) Pension Plan, Retirement Income Maintenance Plan (the "RIM Plan") Post-retirement Plan, Split-Dollar Life Insurance Plans (cont'd) For the Year Ended December 31, 2019 Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance Affected Line Item in the Consolidated Statements of Income (In thousands) Service cost $ 6,494 $ 210 $ 339 $ 354 Compensation and employee benefits Interest cost 8,569 466 826 457 Other non-interest expense Expected return on plan assets (21,058) — — — Other non-interest expense Amortization: Prior service cost — — — 56 Other non-interest expense Net loss 3,070 244 147 247 Other non-interest expense Net periodic (income) benefit cost $ (2,925) $ 920 $ 1,312 $ 1,114 For the Year Ended December 31, 2018 Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance Affected Line Item in the Consolidated Statements of Income (In thousands) Service cost $ 7,805 $ 282 $ 417 $ 374 Compensation and employee benefits Interest cost 8,489 443 796 428 Other non-interest expense Expected return on plan assets (20,794) — — — Other non-interest expense Amortization: Prior service cost — — (106) 32 Other non-interest expense Net loss 3,117 413 323 506 Other non-interest expense Net periodic (income) benefit cost $ (1,383) $ 1,138 $ 1,430 $ 1,340 The following table summarizes the impact of retrospective application of ASU 2017-07 to the Consolidated Statements of Income for the year ended December 31, 2018: Year Ended December 31, 2018 (In thousands) Compensation and employee benefits: As previously reported $ 69,907 As reported under ASU 2017-07 77,226 Other non-interest expense: As previously reported $ 12,916 As reported under ASU 2017-07 5,597 (14) Employee Benefit Plans (continued) Pension Plan, Retirement Income Maintenance Plan (the "RIM Plan") Post-retirement Plan, Split-Dollar Life Insurance Plans (cont'd) The weighted average actuarial assumptions used in the plan determinations at and for the years ended December 31, 2020, 2019, and 2018 were as follows: At and For the Years Ended December 31, 2020 Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance Weighted average assumptions used to determine benefit obligation: Discount rate 2.920 % 2.670 % 2.590 % 3.010 % Rate of compensation increase 3.750 3.750 N/A 3.750 Weighted average assumptions used to determine net periodic benefit cost: Discount Rates: Benefit obligation 3.490 % 3.330 % 3.270 % 3.540 % Remeasurement rate 2.740 N/A N/A N/A Service cost 3.660 3.460 3.520 3.710 Remeasurement rate 2.970 N/A N/A N/A Interest cost 3.120 3.000 2.850 3.280 Remeasurement rate 2.220 N/A N/A N/A Expected rate of return on plan assets 6.500 N/A N/A N/A Rate of compensation increase 3.500 3.500 N/A 3.500 At and For the Years Ended December 31, 2019 Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance Weighted average assumptions used to determine benefit obligation: Discount rate 3.490 % 3.330 % 3.270 % 3.540 % Rate of compensation increase 3.500 3.500 N/A 3.500 Weighted average assumptions used to determine net periodic benefit cost: Discount Rates: Benefit obligation 4.570 % 4.470 % 4.410 % 4.630 % Remeasurement rate 3.850 N/A N/A N/A Service cost 4.700 4.570 4.600 4.740 Remeasurement rate 4.040 N/A N/A N/A Interest cost 4.250 4.180 4.050 4.390 Remeasurement rate 3.440 N/A N/A N/A Expected rate of return on plan assets 7.000 N/A N/A N/A Rate of compensation increase 3.500 3.500 N/A 3.500 (14) Employee Benefit Plans (continued) Pension Plan, Retirement Income Maintenance Plan (the "RIM Plan") Post-retirement Plan, Split-Dollar Life Insurance Plans (cont'd) At and For the Years Ended December 31, 2018 Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance Weighted average assumptions used to determine benefit obligation: Discount rate 4.570 % 4.470 % 4.410 % 4.630 % Rate of compensation increase 3.500 3.500 N/A 3.500 Weighted average assumptions used to determine net periodic benefit cost: Discount Rates: Benefit obligation 3.750 % 4.470 % 3.625 % 3.750 % Service cost N/A 4.570 N/A N/A Interest cost N/A 4.180 N/A N/A Expected rate of return on plan assets 7.250 N/A N/A N/A Rate of compensation increase 3.500 3.500 N/A 3.500 The Company provides its actuaries with certain rate assumptions used in measuring the respective benefit obligations. The most significant of these is the discount rate used to calculate the period-end present value of the benefit obligations, and the expense to be included in the following year's financial statements. A lower discount rate will result in a higher benefit obligation and expense, while a higher discount rate will result in a lower benefit obligation and expense. The discount rate assumption was determined based on a cash flow-yield curve model specific to the Company's pension and post-retirement plans. The Company compares this rate to certain market indices, such as long-term treasury bonds, or pension liability indices, for reasonableness. The Company's expected return on plan assets assumption is based on historical investment return rate experience and evaluation of input from the trustee managing the pension plan's assets and the Bank's Pension Committee which has responsibility for managing these assets. The expected return on pension plan assets is also impacted by the target allocation of assets, which is based on the Company's goal of earning the highest rate of return while maintaining risk at acceptable levels. Assumed health care cost trend rates have a significant effect on the amounts reported for health care plans. A 1% change in the assumed health care cost trend rate would have the following effects on post-retirement benefits at December 31, 2020: 1% increase 1% decrease (In thousands) Effect on total service cost and interest cost $ 19 $ (16) Effect on post-retirement benefit obligations 175 (154) (14) Employee Benefit Plans (continued) Pension Plan, Retirement Income Maintenance Plan (the "RIM Plan") Post-retirement Plan, Split-Dollar Life Insurance Plans (cont'd) Estimated future benefit payments, which reflect expected future service, as appropriate for the next five years and thereafter are as follows: Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance (In thousands) 2021 $ 8,568 $ 384 $ 1,490 $ 270 2022 9,141 436 1,525 312 2023 9,847 534 1,559 363 2024 10,592 673 1,622 412 2025 11,388 778 1,675 461 2026 - 2030 68,978 4,415 8,820 3,179 The weighted average asset allocation of pension assets at December 31, 2020 and 2019 were as follows: December 31, 2020 2019 Domestic equities 44.1 % 39.6 % Foreign equities 13.4 % 9.6 % Fixed income 37.8 % 44.3 % Real estate 4.4 % 6.1 % Cash 0.3 % 0.4 % Total 100.0 % 100.0 % Management, under the direction of the Pension Committee, strives to have pension assets sufficiently diversified so that adverse or unexpected results from one security class will not have a significant detrimental impact on the entire portfolio. The target allocation of assets and acceptable ranges around the targets are as follows: Allowable Range Equities 40-60% Fixed income 40-60% Real estate 0-10% Cash 0-15% The Pension Committee engages an investment management advisory firm to regularly monitor the performance of the asset managers and ensure they are within compliance with policy. The maximum and minimum of the range for each class is based on the fair value of the assets in the fund. If changes in fair value should lead to allocations outside these boundaries, management shall adjust exposure back to the established guidelines within 90 days or reevaluate the guidelines. The following tables present the assets that are measured at fair value on a recurring basis by level within the U.S. GAAP fair value hierarchy as reported on the Statements of Net Assets Available for Plan Benefits at December 31, 2020 and 2019, respectively. A financial instrument's level within the fair value hierarchy's is based on the lowest level of input that is significant to the fair value measurement. (14) Employee Benefit Plans (continued) Pension Plan, Retirement Income Maintenance Plan (the "RIM Plan") Post-retirement Plan, Split-Dollar Life Insurance Plans (cont'd) December 31, 2020 Fair Value Measurements Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In thousands) Money market mutual funds $ 1,434 $ 1,434 $ — $ — Mutual funds - value stock fund 29,914 29,914 — — Mutual funds - fixed income 155,864 155,864 — — Mutual funds - international stock 55,300 55,300 — — Mutual funds - institutional stock index 151,436 151,436 — — Commingled real estate funds 17,959 — 17,959 — $ 411,907 $ 393,948 $ 17,959 $ — December 31, 2019 Fair Value Measurements Fair value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In thousands) Money market mutual funds $ 1,462 $ 1,462 $ — $ — Mutual funds - value stock fund 27,827 27,827 — — Mutual funds - fixed income 158,030 158,030 — — Mutual funds - international stock 34,332 34,332 — — Mutual funds - institutional stock index 113,100 113,100 — — Commingled real estate funds 21,596 — 21,596 — $ 356,347 $ 334,751 $ 21,596 $ — Money market and other mutual funds are reported at fair value in the tables above utilizing exchange quoted prices in active markets for identical instruments (Level 1 inputs). The commingled real estate funds are reported at their respective net asset values (Level 2 inputs). Bank-owned life insurance ("BOLI") The Company has BOLI which is a tax-advantaged transaction that is used to partially fund obligations associated with employee compensation and benefit programs. Policies are purchased insuring officers of the Company using a single premium method of payment. BOLI is accounted for using the cash surrender value and the increase in cash surrender value is included in non-interest income in the Company's Consolidated Statements of Income. At December 31, 2020 and 2019, the Company had $232.8 million and $211.4 million, respectively, in BOLI. BOLI income for the years ended December 31, 2020, 2019, and 2018 was $6.6 million, $5.8 million, and $5.2 million, respectively. (14) Employee Benefit Plans (continued) Savings Income Maintenance Deferred Compensation Plan (the "SIM Plan") The Company also maintains a non-qualified defined contribution plan that provides supplemental benefits to certain executives who are prevented from receiving the full benefits contemplated by the 401(k) Plan under tax law limits for tax-qualified plans. The contribution expense for the years ended December 31, 2020, 2019, and 2018 was approximately $4,000, $11,000, and $9,000, respectively. 401(k) Plan The Company has a 401(k) plan covering substantially all employees of the Bank. The Bank may match a percentage of the first 3.00% to 4.50% contributed by participants. The Bank’s matching contribution, if any, is determined by the Board of Directors in its sole discretion. The expense for the years ended December 31, 2020, 2019, and 2018 was approximately $1.7 million, $1.4 million, and $1.3 million,, respectively. Employee Stock Ownership Plan ("ESOP") Effective upon the consummation of the Company's reorganization in April 2018, an ESOP was established for all eligible employees. The ESOP used $45.4 million in proceeds from a twenty Each year, the Bank makes discretionary contributions to the ESOP, which are equal to principal and interest payments required on the term loan. Shares purchased with the loan proceeds were initially pledged as collateral for the term loan and is held in a suspense account for future allocation among participants. Contributions to the ESOP and shares released form the suspense account are allocated among the participants on the basis of compensation, as described by the ESOP, in the year of allocation. The ESOP shares pledged as collateral are reported as unearned ESOP shares in the Consolidated Statements of Financial Condition. As shares are committed to be released from collateral, the Bank reports compensation expense equal to the average market price of the shares during the year, and the shares become outstanding for basic net income per common share computations. ESOP compensation expense for the years ended December 31, 2020, 2019, and 2018 was $3.2 million, $3.6 million and $2.6 million, respectively. The ESOP shares were as follows: December 31, 2020 2019 (In thousands) Allocated shares 606 385 Unearned shares 3,929 4,156 Total ESOP shares 4,535 4,541 Fair value of unearned ESOP shares $ 61,139 $ 70,409 The Company has a SERP, which is a non-qualified plan which provides supplemental retirement benefits to eligible officers (those designated by the Board of Directors) of the Company who are prevented from receiving the full benefits contemplated by the ESOP's benefit formulas under tax law limits for tax-qualified plans. SERP compensation expense for the years ended December 31, 2020, 2019, and 2018 was $215,000, $267,000, and $165,000, respectively. Through the acquisition of Roselle, the Company acquired a non-contributory defined benefit supplemental executive retirement plan with the only participant being the former president of Roselle Bank. For the year ended December 31, 2020, the Company recorded a net periodic benefit cost of $11,000 in connection with this plan. (14) Employee Benefit Plans (continued) Stock Based Deferral Plan and Directors Deferred Compensation Plan In addition, the Bank maintains a stock based deferral plan for certain executives and directors, and a cash based deferred compensation plan for directors. The Company records a deferred compensation equity account and corresponding contra-equity account for the cost of the shares held by the Stock Based Deferral Plan. Periodic adjustments to market are not required as participants do not have the option to take the distribution in cash. The Company records a liability for the amount deferred under the Directors Deferred Compensation Plan. There were no expenses recorded under these plans. Stock Based Compensation At the Company's annual meeting held on June 6, 2019, stockholders approved the Columbia Financial, Inc. 2019 Equity Incentive Plan ("2019 Plan") which provides for the issuance of up to 7,949,996 shares (2,271,427 restricted stock awards and 5,678,569 stock options) of common stock. On July 23, 2019, 1,389,570 shares of restricted stock were awarded, with a grant date fair value of $15.60 per share. To fund the grant of restricted common stock, the Company issued shares from authorized unissued shares. On December 16, 2019, 74,673 shares of restricted stock were awarded, with a grant date fair value of $17.00 per share. To fund the grant of restricted common stock, the Company reissued shares from treasury stock. On December 14, 2020, 33,160 shares of restricted stock were awarded, with a grant date fair value of $15.08 per share. To fund the grant, the Company reissued shares from treasury stock. Restricted shares granted under the 2019 Plan generally vest in equal installments, over the performance or service periods ranging from 1 year to 5 years, beginning 1 year from the date of grant. A portion of restricted shares awarded are performance vesting awards, which may or may not vest depending upon the attainment of certain corporate financial targets. Management recognizes compensation expense for the fair value of restricted shares on a straight line basis over the requisite performance or service period. During the years ended December 31, 2020 and 2019, approximately $5.6 million and $2.3 million, respectively, in expense was recognized in regard to these awards. There was no restricted stock expense recorded for the year ended December 31, 2018. The expected future compensation expense related to the 1,263,169 non-vested restricted shares outstanding at December 31, 2020 is approximately $14.6 million over a weighted average period of 3.0 years. The following is a summary of the Company's restricted stock activity during the years ended December 31, 2020 and 2019: Number of Restricted Shares Weighted Average Grant Date Fair Value Non-vested at January 1, 2019 — $ — Grants 1,464,243 15.67 Forfeited (44,231) 15.60 Non-vested at December 31, 2019 1,420,012 $ 15.67 Grants 33,160 15.08 Vested (172,756) 15.66 Forfeited (17,247) 16.02 Non-vested at December 31, 2020 1,263,169 $ 15.66 (14) Employee Benefit Plans (continued) Stock Based Compensation (continued) On July 23, 2019, options to purchase 3,707,901 shares of Company common stock were awarded with a grant date fair value of $4.25 per option. Stock options granted under the 2019 Plan vest in equal installments over the service period of five years beginning one year from the date of grant. Stock options were granted at an exercise price of $15.60, which represents the fair value of the Company's common stock price on the grant date based on the closing market price, and have an expiration period of 10 years. The fair value of stock options granted was estimated utilizing the Black-Scholes option pricing model using the following assumptions: expected life of 6.5 years, risk-free rate of return of 1.90%, volatility of 22.12%, and a dividend yield of 0.00%. On December 16, 2019, options to purchase 184,378 shares of Company common stock were awarded with a grant date fair value of $4.59 per option. Stock options granted under the 2019 Plan generally vest in equal installments over the service period of five years beginning one year from the date of grant. Stock options were granted at an exercise price of $17.00, which represents the fair value of the Company's common stock price on the grant date based on the closing market price, and have an expiration period of approximately 10 years. The fair value of stock options granted was estimated utilizing the Black-Scholes option pricing model using the following assumptions: expected life of 6.5 years, risk-free rate of return of 1.79%, volatility of 22.23%, and a dividend yield of 0.00%. The expected life of the options represents the period of time that stock options are expected to be outstanding and is estimated using the simplified approach, which assumes that all outstanding options will be exercised at the midpoint of the vesting date and full contractual term. The risk-free rate of return is based on the rates on the grant date of a U.S. Treasury Note with a term equal to the expected option life. Since the Company recently converted to a public Company and does not have sufficient historical price data, the expected volatility is based on the historical daily stock prices of a peer group of similar entities based on factors such as industry, stage of life cycle, size and financial leverage. The Company has not paid any cash dividends on its common stock. Management recognizes expense for the fair value of these awards on a straight line basis over the requisite service period. During the years ended December 31, 2020 and 2019, approximately $3.2 million and $1.4 million, respectively, in expense was recognized in regard to these awards. There was no stock option expense recorded for the year ended December 31, 2018. The expected future compensation expense related to the 2,965,330 non-vested options outstanding at December 31, 2020 is $11.3 million over a weighted average period of 3.6 years. The following is a summary of the Company's option activity during the years ended December 31, 2020 and 2019: Number of Stock Options Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Outstanding January 1, 2019 — $ — — $ — Granted 3,892,279 15.60 9.6 — Forfeited (108,235) 15.60 — — Outstanding, December 31, 2019 3,784,044 $ 15.67 9.6 $ 4,812,490 Expired (10,457) 15.98 — — Forfeited (64,959) 15.84 — — Outstanding, December 31, 2020 3,708,628 $ 15.66 8.6 $ — Options exercisable at December 31, 2020 743,298 $ 15.66 8.5 $ — The aggregate intrinsic value in the table above represents the total pre-tax intrinsic value, the difference between the Company's closing stock price on the last trading day of the period and the exercise price, multiplied by the number of in-the-money options. There were no stock option exercises during the years ended December 31, 2020, 2019 and 2018.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The current and deferred amounts of income tax expense (benefit) for the years ended December 31, 2020, 2019, and 2018 are as follows: Years Ended December 31, 2020 2019 2018 (In thousands) Current: Federal $ 5,072 $ 5,933 $ 11,284 State 3,844 2,905 5,129 Total current 8,916 8,838 16,413 Deferred: Federal 9,847 8,275 (4,901) State (109) (748) (589) Total deferred 9,738 7,527 (5,490) Total income tax expense $ 18,654 $ 16,365 $ 10,923 The Company reported deferred tax expense (benefit) of $(5.6) million, $(5.5) million, and $1.4 million for the years ended December 31, 2020, 2019, and 2018, respectively, related to the unrealized gains (losses) on securities available for sale, which is reported in accumulated other comprehensive income (loss), net of tax. Additionally, the Company recorded a deferred tax (benefit) expense of $900,000, $779,000, and $(530,000), respectively, related to the reclassification adjustment of actuarial net (loss) gain on employee benefit obligations, which is reported in accumulated other comprehensive income, net of tax. Deferred tax expense for the years ended December 31, 2020 and 2019 also includes $5.4 million and $2.3 million, respectively, recorded as a result of purchase accounting related to the Roselle and Stewardship acquisitions. A reconciliation between the amount of reported total income tax expense and the amount computed by multiplying the applicable statutory federal income tax rate of 21% is as follows: Years Ended December 31, 2020 2019 2018 (In thousands) Tax expense at applicable statutory rate $ 16,013 $ 14,927 $ 7,067 Increase (decrease) in taxes resulting from: State tax, net of federal income tax benefit 2,951 1,704 3,587 ESOP fair market value adjustment 187 272 202 Tax exempt interest income (11) (6) (4) Income from Bank-owned life insurance (1,075) (1,246) (812) Dividend received deduction (9) (8) (16) Non-deductible merger-related expenses 42 222 — Non-deductible compensation expense — 398 — Other, net 556 102 899 Total income tax expense $ 18,654 $ 16,365 $ 10,923 (15) Income Taxes (continued) The net deferred tax asset is included in other assets in the Consolidated Statements of Financial Condition. The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at December 31, 2020 and 2019 are as follows: At December 31, 2020 2019 (In thousands) Deferred tax assets: Allowance for loan losses $ 20,878 $ 13,114 Post-retirement benefits 5,928 4,089 Deferred compensation 2,779 2,085 Depreciation — 1,002 Retirement Income Maintenance plan 2,471 1,725 ESOP 624 301 Stock-based compensation 2,724 788 Reserve for uncollected interest 126 54 Net unrealized losses on debt securities and defined benefit plans 18,511 18,374 Federal and State NOLs 9,719 2,063 Alternative minimum assessment carryforwards 2,156 2,156 Charitable contribution carryforward 6,359 5,981 Purchase accounting 1,024 — Lease liability 5,609 — Other items 3,215 332 Gross deferred tax assets 82,123 58,999 Valuation allowance (3,411) (7,442) 78,712 51,557 Deferred tax liabilities: Pension expense 49,225 33,856 Depreciation 6,118 — Deferred loan costs 8,555 5,911 Intangible assets 1,597 1,215 Lease right-of-use asset 5,317 — Other items 716 266 Total gross deferred tax liabilities 71,528 41,248 Net deferred tax asset $ 7,184 $ 10,309 Retained earnings at December 31, 2020 and 2019 includes approximately $21.5 million for which no provision for income tax has been made. This amount represents an allocation of income to bad debt deductions for tax purposes only. Events that would result in taxation of these reserves include the failure to qualify as a bank for tax purposes, distributions in complete or partial liquidation, stock redemptions and excess distributions to stockholders. Management believes that not all existing net deductible temporary differences that comprise the net deferred tax asset will reverse during periods in which the Company generates sufficient net taxable income. Accordingly, management has established a valuation allowance. Significant changes in the Company's operations and or economic conditions could affect the benefits of the recognized net deferred tax asset. Based on all available evidence, a valuation allowance was established for the portion of the state tax benefit that is not more likely than not to be realized. At December 31, 2020 and 2019, the Company's valuation allowance totaled $3.4 million and $7.4 million, respectively. Based upon projections of future taxable income and the ability to carryforward net (15) Income Taxes (continued) operating losses indefinitely, management believes it is more likely than not the Company will realize the remaining deferred tax assets. The Company had federal net operating losses from the acquisition of Roselle of approximately $11.9 million at December 31, 2020 and approximately $5.8 million from the acquisition of Stewardship of at December 31, 2019. These net operating losses are subject to a $1.1 million annual limitation under Code Section 382 and will not expire, except for approximately $1.0 million that will begin to expire in 2036. The Company had New Jersey net operating loss carryforwards of $108.4 million and $99.8 million, respectively, at December 31, 2020 and 2019. If not utilized, these carryforwards will expire periodically through 2039. At both December 31, 2020 and 2019, the Company had approximately $2.2 million of New Jersey AMA Tax Credits. These credits do not expire. The Company files income tax returns in the United States federal jurisdiction and in the states of New Jersey, New York and Pennsylvania. At December 31, 2020, the Company is no longer subject to federal income tax examination for the years prior to 2016. Columbia Bank MHC and its subsidiaries' New York returns are currently under audit for the tax years 2016 and 2017. The Company is open for examination by the State of New Jersey for years after 2015 and by the States of Pennsylvania and New York for years after 2016.

Financial Transactions with Off

Financial Transactions with Off-Balance-Sheet Risk and Concentrations of Credit Risk	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Financial Transactions with Off-Balance-Sheet Risk and Concentrations of Credit Risk	Financial Transactions with Off-Balance-Sheet Risk and Concentrations of Credit Risk The Company is a party to financial instruments with off-balance-sheet risk in the normal course of business in order to meet the financing needs of its customers. These financial instruments consist of commitments to extend credit and involve, to varying degrees, elements of credit and interest rate risk in excess of the amounts recognized in the Consolidated Statements of Financial Condition. At December 31, 2020 and 2019, the following commitments existed which are not reflected in the Consolidated Statements of Financial Condition: December 31, 2020 2019 (In thousands) Loan commitments: Residential real estate $ 149,847 $ 91,141 Multifamily and commercial real estate 98,910 95,025 Commercial business 16,842 18,737 Construction 13,335 59,990 Consumer including home equity loans and advances 3,264 5,988 Total loan commitments $ 282,198 $ 270,881 Unused lines of credit consisting of home equity lines, and undisbursed business and construction lines totaled approximately $894.5 million and $910.0 million as of December 31, 2020 and 2019, respectively. Amounts drawn on the unused lines of credit are predominantly assessed interest at rates that fluctuate with the base rate. The Company uses the same credit policies and collateral requirements in making commitments and conditional obligations as it does for on-balance-sheet loans. Commitments to extend credit are agreements to lend customers as long as there is no violation of any condition established in the contract. Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. Since the commitments may expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements. The Company evaluates each customer's creditworthiness on a case-by-case basis. The amount of collateral obtained, if deemed necessary by the Company upon extension of credit, is based on management's credit evaluation of the borrower. (16) Financial Transactions with Off-Balance-Sheet Risk and Concentrations of Credit Risk (continued) The Company principally grants residential real estate loans, multifamily and commercial real estate loans, construction loans, commercial business loans, home equity loans and advances and other consumer loans to borrowers primarily throughout New Jersey, New York and Pennsylvania, and to a much lesser extent in a few other east coast states. Its borrowers' abilities to repay their obligations are dependent upon various factors, including the borrowers' income and net worth, cash flows generated by the underlying collateral, if any, or from business operations, value of the underlying collateral and priority of the Company's lien on the property. These factors are dependent on various economic conditions and circumstances beyond the Company's control, and as a result, the Company is subject to the risk of loss. The Company believes that its lending policies and procedures adequately minimize the potential exposure to such risks and adequate provisions for loan losses are provided for all probable and estimable losses. In the normal course of business, the Company sells residential real estate loans to third parties. These loan sales are subject to customary representations and warranties. In the event that the Company is found to be in breach of these representations and warranties, it may be obligated to repurchase certain of these loans. The Company has entered into derivative financial instruments to manage exposures that arise from business activities that result in the receipt or payment of future known and uncertain cash amounts, the value of which are determined by interest rates. The Company's derivative financial instruments are used to manage differences in the amount, timing, and duration of the Company's known or expected cash receipts and its known or expected cash payments principally related to the Company's borrowings. These derivatives were used to hedge the variability in cash flows associated with certain short-term funding transactions. The fair value of the derivatives as of December 31, 2020 and 2019 was a net liability of $23.0 million and $11.4 million, respectively, net of accrued interest and variation margin posted in accordance with the Chicago Mercantile Exchange. In connection with its mortgage banking activities, at December 31, 2020 the Company had no commitments to sell loans, with servicing retained by the Bank. At December 31, 2020, the Company had commitments classified as held-for-sale, to sell the loans without servicing retained by the Bank. In addition to the commitments noted above, the Company is party to standby letters of credit which are conditional commitments issued by the Bank to guarantee the performance of a customer to a third party. The guarantees generally extend for a term of up to one year and may be secured or unsecured. Outstanding letters of credit totaled $9.4 million and $8.4 million at December 31, 2020 and 2019, respectively. In the normal course of business, there are outstanding various legal proceedings, claims, and contingent liabilities which are not included in the consolidated financial statements. In the opinion of management, the financial position of the Company will not be materially affected by the outcome of such legal proceedings and claims.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The Company utilizes fair value measurements to record fair value adjustments to certain assets and liabilities and to determine fair value disclosures. The determination of fair values of financial instruments often requires the use of estimates. Where quoted market values in an active market are not readily available, the Company utilizes various valuation techniques to estimate fair value. In January 2016, the FASB issued ASU 2016-01- "Financial Instruments". This guidance amended existing guidance to improve accounting standards for financial instruments including clarification and simplification of the accounting and disclosure requirements and the requirement to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes. The Company adopted the guidance effective January 1, 2019, and the fair value of the Company's loan portfolio is now presented using an exit price method. Fair value is the exchange price that would be received for an asset or paid to transfer a liability (exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. There are three levels of inputs that may be used to measure the fair values: Level 1: Unadjusted quoted prices for identical assets or liabilities in active markets that the Company has the ability to access on the measurement date. Level 2: Inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. These might include quoted prices for similar instruments in markets that are active or not active, or inputs that are observable or can be corroborated by observable market data for substantially the full term of the asset or liability. Level 3: Prices or valuation techniques that require unobservable inputs that are both significant to the fair value measurement and unobservable (i.e., supported by minimal or no market activity). Valuation techniques include the use of option pricing models, discounted cash flow models and similar techniques. A financial instrument’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. Assets and Liabilities Measured at Fair Value on a Recurring Basis The methods described below were used to measure fair value of financial instruments as reflected in the tables below on a recurring basis as of December 31, 2020 and 2019. Debt Securities Available for Sale, at Fair Value For debt securities available for sale, fair value was estimated using a market approach. The majority of these securities are fixed income instruments that are not quoted on an exchange, but are traded in active markets. Prices for these instruments are obtained through third-party data service providers or dealer market participants with which the Company has historically transacted both purchases and sales of securities. Prices obtained from these sources include market quotations and matrix pricing. Matrix pricing, a Level 2 input, is a mathematical technique used principally to value certain securities to a benchmark or to comparable securities. The Company evaluates the quality of Level 2 matrix pricing through comparison to similar assets with greater liquidity and evaluation of projected cash flows. As the Company is responsible for the determination of fair value, it performs quarterly analysis on the prices received from the pricing service to determine whether the prices are reasonable estimates of fair value. Specifically, the Company compares the prices received from the pricing service to a secondary pricing source. Additionally, the Company compares changes in the reported market values and returns to relevant market indices to assess the reasonableness of the reported prices. The Company’s internal price verification procedures and review of fair value methodology documentation provided by independent pricing services has not historically resulted in an adjustment in the prices obtained from the pricing service. The Company may hold debt instruments issued by the U.S. government and U.S. government-sponsored agencies that are traded in active markets with readily accessible quoted market prices that are considered Level 1 inputs. (17) Fair Value Measurements (continued) Equity Securities, at Fair Value The Company holds equity securities that are traded in active markets with readily accessible quoted market prices that are considered Level 1 inputs. A trust preferred security that is not traded in an active market and Federal Home Loan Mortgage Corporation ("FHLMC") and Federal National Mortgage Association ("FNMA") preferred stock, are considered Level 2 instruments. In addition, Level 2 instruments include Atlantic Community Bankers Bank ("ACBB") stock, which is based on redemption at par value and can only be sold to the issuing ACBB or another institution that holds ACBB stock. Derivatives The Company records all derivatives included in other assets and liabilities on the Consolidated Statements of Financial Condition at fair value. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative, whether the Company has elected to designate a derivative in a hedging relationship and apply hedge accounting, and whether the hedging relationship has satisfied the criteria necessary to apply hedge accounting. See note 22 for disclosures related to the accounting treatment for derivatives. The fair value of the Company's derivatives is determined using discounted cash flow analysis using observable market-based inputs, which are considered Level 2 inputs. The following tables present the assets and liabilities reported on the Consolidated Statements of Financial Condition at their fair values as of December 31, 2020 and 2019, by level within the fair value hierarchy: December 31, 2020 Fair Value Measurements Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In thousands) Debt securities available for sale: U.S. government and agency obligations $ 25,549 $ 25,549 $ — $ — Mortgage-backed securities and collateralized mortgage obligations 1,200,394 — 1,200,394 — Municipal obligations 16,862 — 16,862 — Corporate debt securities 69,477 — 69,477 — Trust preferred securities 4,670 — 4,670 — Total debt securities available for sale 1,316,952 25,549 1,291,403 — Equity securities 5,418 5,072 346 — Derivative assets 19,425 — 19,425 — $ 1,341,795 $ 30,621 1,311,174 $ — Derivative liabilities $ 42,384 $ — $ 42,384 $ — (17) Fair Value Measurements (continued) December 31, 2019 Fair Value Measurements Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In thousands) Debt securities available for sale: U.S. government and agency obligations $ 42,386 $ 42,386 $ — $ — Mortgage-backed securities and collateralized mortgage obligations 979,881 — 979,881 — Municipal obligations 2,284 — 2,284 — Corporate debt securities 69,180 — 69,180 — Trust preferred securities 4,605 — 4,605 — Total debt securities available for sale 1,098,336 42,386 1,055,950 — Equity securities 2,855 2,587 268 — Derivative assets 185 — 185 — $ 1,101,376 $ 44,973 $ 1,056,403 $ — Derivative liabilities $ 11,546 $ — $ 11,546 $ — There were no Level 3 assets measured at fair value on a recurring basis at December 31, 2020 and 2019. Assets Measured at Fair Value on a Non-Recurring Basis The valuation techniques described below were used to estimate fair value of financial instruments measured on a non-recurring basis as of December 31, 2020 and 2019. Collateral Dependent Impaired Loans Loans which meet certain criteria are evaluated individually for impairment. For loans measured for impairment based on the fair value of the underlying collateral, fair value was estimated using a market approach. The Company measures the fair value of collateral underlying impaired loans primarily through obtaining independent appraisals that rely upon quoted market prices for similar assets in active markets. These appraisals include adjustments, on an individual case-by-case basis, to comparable assets based on the appraisers’ market knowledge and experience, as well as adjustments for estimated costs to sell between 6% and 8%. The Company classifies these loans as Level 3 within the fair value hierarchy. Mortgage Servicing Rights, Net ("MSR"s") Mortgage servicing rights are carried at the lower of cost or estimated fair value. The estimated fair value of MSRs is obtained through an analysis of future cash flows, incorporating assumptions that market participants would use in determining fair value including market discount rates, prepayments speeds, servicing income, servicing costs, default rates and other market driven data, including the market's perception of future interest rate movements. The prepayment speed and the discount rate are considered two of the most significant inputs in the model. A significant degree of judgment is involved in valuing the mortgage servicing rights using Level 3 inputs. The use of different assumptions could have a significant effect on this fair value estimate. (17) Fair Value Measurements (continued) The following tables present the assets and liabilities reported on the Consolidated Statements of Financial Condition at their fair values on a non-recurring basis at December 31, 2020 and 2019, by level within the fair value hierarchy: December 31, 2020 Fair Value Measurements Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In thousands) Mortgage servicing rights $ 1,338 $ — $ — $ 1,338 $ 1,338 $ — $ — $ 1,338 December 31, 2019 Fair Value Measurements Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In thousands) Impaired loans $ 1,063 $ — $ — $ 1,063 Mortgage servicing rights 681 — — 681 $ 1,744 $ — $ — $ 1,744 The following table presents information for Level 3 assets measured at fair value on a non-recurring basis at December 31, 2020 and 2019: December 31, 2020 Fair Value Valuation Methodology Unobservable Inputs Range of Inputs Weighted Average (Dollars in thousands) Mortgage servicing rights $ 1,338 Estimated cash flow Prepayment speeds and discount rates (2) 9.7% - 26.2% 16.7% December 31, 2019 Fair Value Valuation Methodology Unobservable Inputs Range of Inputs Weighted Average (Dollars in thousands) Impaired loans $ 1,063 Estimated cash flow Expected value of future cash flows (1) —% —% Mortgage servicing rights 681 Estimated cash flow Prepayment speeds and discount rates (3) 3.6% - 24.0% 12.7% (1) Value based on management's estimate of expected future cash flows. (2) Value of SBA servicing rights based on a discount rate of 10.25%. (3) Value of SBA servicing rights based on a discount rate of 11.75%. (17) Fair Value Measurements (continued) Other Fair Value Disclosures The Company is required to disclose estimated fair value of financial instruments, both assets and liabilities on and off the balance sheet, for which it is practicable to estimate fair value. A description of the valuation methodologies used for those assets and liabilities not recorded at fair value on a recurring or non-recurring basis are set forth below. Cash and Cash Equivalents For cash and due from banks, federal funds sold and short-term investments, the carrying amount approximates fair value due to their nature and short-term maturities. Debt Securities Held to Maturity For debt securities held to maturity, fair value was estimated using a market approach. The majority of the Company’s securities are fixed income instruments that are not quoted on an exchange, but are traded in active markets. Prices for these instruments are obtained through third-party data service providers or dealer market participants with which the Company has historically transacted both purchases and sales of securities. Prices obtained from these sources include market quotations and matrix pricing. Matrix pricing, a Level 2 input, is a mathematical technique used principally to value certain securities to benchmark or to compare securities. The Company evaluates the quality of Level 2 matrix pricing through comparison to similar assets with greater liquidity and evaluation of projected cash flows. As the Company is responsible for the determination of fair value, it performs quarterly analysis on the prices received from the pricing service to determine whether the prices are reasonable estimates of fair value. Specifically, the Company compares the prices received from the pricing service to a secondary pricing source. Additionally, the Company compares changes in the reported market values and returns to relevant market indices to assess the reasonableness of the reported prices. The Company’s internal price verification procedures and review of fair value methodology documentation provided by independent pricing services has not historically resulted in an adjustment in the prices obtained from the pricing service. The Company also holds debt instruments issued by the U.S. government and U.S. government sponsored agencies that are traded in active markets with readily accessible quoted market prices that are considered Level 1 inputs within the fair value hierarchy. Federal Home Loan Bank Stock ("FHLB") The fair value of FHLB stock is based on redemption at par value and can only be sold to the issuing FHLB, to other FHLBs, or to other member banks. As such, the Company's FHLB stock is recorded at cost, or par value, and is evaluated for impairment each reporting period by considering the ultimate recoverability of the investment rather than temporary declines in value. The Company classifies the estimated fair value as Level 2 within the fair value hierarchy. Loans Receivable Fair values are estimated for portfolios of loans with similar financial characteristics. Loans are segregated by type such as commercial mortgage, residential mortgage, commercial, construction, and consumer and other. Each loan category is further segmented into fixed and adjustable rate interest terms and into performing and non-performing categories. The fair value of performing loans was estimated using a combination of techniques, including a discounted cash flow model that utilizes a discount rate that reflects the Company's current pricing for loans with similar characteristics and remaining maturity, adjusted by an amount for estimated credit losses inherent in the portfolio at the balance sheet date. The rates take into account the expected yield curve, as well as an adjustment for prepayment risk, when applicable. The Company classifies the estimated fair value of its loan portfolio as Level 3. The fair value for significant non-performing loans was based on recent external appraisals of collateral securing such loans, adjusted for the timing of anticipated cash flows. The Company classifies the estimated fair value of its non-performing loan portfolio as Level 3. Deposits The fair value of deposits with no stated maturity, such as demand, money market, and savings and club deposits are payable on demand at each reporting date and classified as Level 2. The estimated fair value of certificates of deposit was based on the discounted value of contractual cash flows. The discount rate was estimated using the Company’s current rates offered for deposits with similar remaining maturities. The Company classifies the estimated fair value of its certificates of deposit portfolio as Level 2. (17) Fair Value Measurements (continued) Borrowings The fair value of borrowings was estimated by discounting future cash flows using rates available for debt with similar terms and maturities and is classified by the Company as Level 2 within the fair value hierarchy. Commitments to Extend Credit and Letters of Credit The fair value of commitments to extend credit and letters of credit was estimated using the fees currently charged to enter into similar agreements, taking into account the remaining terms of the agreements and the present creditworthiness of the counter-parties. For fixed rate loan commitments, fair value also considers the difference between current levels of interest rates and the committed rates. The fair value estimates of commitments to extend credit and letters of credit are deemed immaterial. The following tables present the assets and liabilities reported on the Consolidated Statements of Financial Condition at their fair values as of December 31, 2020 and 2019: December 31, 2020 Fair Value Measurements Carrying Value Total Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In thousands) Financial assets: Cash and cash equivalents $ 422,957 $ 422,957 $ 422,957 $ — $ — Debt securities available for sale 1,316,952 1,316,952 25,549 1,291,403 — Debt securities held to maturity 262,720 277,091 5,001 272,090 — Equity securities 5,418 5,418 5,072 346 Federal Home Loan Bank stock 43,759 43,759 — 43,759 — Loans receivable, net 6,107,094 6,394,524 — — 6,394,524 Derivative assets 19,425 19,425 — 19,425 — Financial liabilities: Deposits $ 6,778,624 $ 6,793,034 $ — $ 6,793,034 $ — Borrowings 799,364 808,853 — 808,853 — Derivative liabilities 42,384 42,384 — 42,384 — (17) Fair Value Measurements (continued) December 31, 2019 Fair Value Measurements Carrying Value Total Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In thousands) Financial assets: Cash and cash equivalents $ 75,547 $ 75,547 $ 75,547 $ — $ — Debt securities available for sale 1,098,336 1,098,336 42,386 1,055,950 — Debt securities held to maturity 285,756 289,505 19,960 269,545 — Equity securities 2,855 2,855 2,587 268 — Federal Home Loan Bank stock 69,579 69,579 — 69,579 — Loans receivable, net 6,135,857 6,219,008 — — 6,219,008 Derivative assets 185 185 — 185 — Financial liabilities: Deposits $ 5,645,842 $ 5,654,075 $ — $ 5,654,075 $ — Borrowings 1,407,022 1,411,962 — 1,411,962 — Derivative liabilities 11,546 11,546 — 11,546 — Limitations Fair value estimates are made at a specific point in time, based on relevant market information and information about the financial instrument. These estimates do not reflect any premium or discount that could result from offering for sale at one time the Company’s entire holdings of a particular financial instrument. Because limited markets exist for a significant portion of the Company’s financial instruments, fair value estimates are based on judgments regarding future expected loss experience, current economic conditions, risk characteristics of various financial instruments, and other factors. These estimates are subjective in nature and involve uncertainties and matters of significant judgment and, therefore, cannot be determined with precision. Changes in assumptions could significantly affect the estimates.

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data (Unaudited)	Selected Quarterly Financial Data (Unaudited) The following tables are a condensed summary of certain quarterly results of operations for the years ended December 31, 2020, 2019, and 2018: Quarters Ended December 31, 2020 March 31 June 30 September 30 December 31 (Dollars in thousands, except per share data) Total interest income $ 74,690 $ 75,587 $ 72,933 $ 72,501 Total interest expense 23,988 19,716 16,609 13,825 Net interest income 50,702 55,871 56,324 58,676 Provision for credit losses 9,568 5,736 2,516 627 Net interest income after provision for credit losses 41,134 50,135 53,808 58,049 Total non-interest income 6,391 7,008 7,909 9,962 Total non-interest expense 38,508 37,443 41,378 40,810 Income before income tax expense 9,017 19,700 20,339 27,201 Income tax expense 2,252 4,603 5,252 6,547 Net income $ 6,765 $ 15,097 $ 15,087 $ 20,654 Earnings per share - basic and diluted $ 0.06 $ 0.14 $ 0.14 $ 0.19 Weighted average shares outstanding - basic and diluted 108,438,173 111,102,306 110,983,871 108,499,658 Quarters Ended December 31, 2019 March 31 June 30 September 30 December 31 (Dollars in thousands, except per share data) Total interest income $ 62,887 $ 62,732 $ 64,438 $ 71,026 Total interest expense 20,503 21,889 22,722 23,598 Net interest income 42,384 40,843 41,716 47,428 Provision for loan losses 436 112 1,157 2,519 Net interest income after provision for loan losses 41,948 40,731 40,559 44,909 Total non-interest income 6,037 6,775 10,115 8,709 Total non-interest expense 29,559 31,841 31,064 36,237 Income before income tax expense 18,426 15,665 19,610 17,381 Income tax expense 3,507 3,634 5,392 3,832 Net income $ 14,919 $ 12,031 $ 14,218 $ 13,549 Earnings per share - basic and diluted $ 0.13 $ 0.11 $ 0.13 $ 0.12 Weighted average shares outstanding - basic and diluted 111,536,577 111,553,203 111,371,754 109,958,999 (18) Selected Quarterly Financial Data (Unaudited) (continued) Quarters Ended December 31, 2018 March 31 June 30 September 30 December 31 (Dollars in thousands, except per share data) Total interest income $ 51,791 $ 55,019 $ 57,695 $ 61,785 Total interest expense 12,730 14,004 17,112 18,410 Net interest income 39,061 41,015 40,583 43,375 Provision for loan losses 2,000 2,400 1,500 777 Net interest income after provision for loan losses 37,061 38,615 39,083 42,598 Total non-interest income 4,543 5,450 5,290 6,405 Total non-interest expense 26,015 61,768 26,590 31,013 Income (loss) before income tax expense 15,589 (17,703) 17,783 17,990 Income tax expense (benefit) 3,805 (2,961) 6,956 3,123 Net income (loss) $ 11,784 $ (14,742) $ 10,827 $ 14,867 Earnings per share - basic and diluted N/A $ (0.13) $ 0.10 $ 0.13 Weighted average shares outstanding - basic and diluted N/A 111,360,278 111,389,951 111,423,361

Earnings per Share

Earnings per Share	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Earnings per Share	Earnings per Share Basic earnings per share ("EPS") is computed by dividing net income available to common shareholders by the weighted average number of common shares outstanding during the period. For purposes of calculating basic EPS, weighted average common shares outstanding excludes treasury stock, unallocated employee stock ownership plan shares that have not been committed for release and deferred compensation obligations required to be settled in shares of Company stock. Diluted EPS is computed using the same method as basic EPS and reflects the potential dilution which could occur if stock options and unvested shares were exercised and converted into common stock. The potentially diluted shares would then be included in the weighted average number of shares outstanding for the period using the treasury stock method. The following is a reconciliation of the numerators and denominators of the basic and diluted earnings per share calculations for the years ended December 31, 2020, 2019,and 2018: December 31, 2020 2019 2018 (In thousands, except share and per share data) Net income $ 57,603 $ 54,717 $ 22,736 Shares: Weighted average shares outstanding - basic 109,755,924 111,101,246 111,395,723 Weighted average dilutive shares outstanding — — — Weighted average shares outstanding - diluted 109,755,924 111,101,246 111,395,723 Earnings per share: Basic $ 0.52 $ 0.49 $ 0.20 Diluted $ 0.52 $ 0.49 $ 0.20

Parent-only Financial Informati

Parent-only Financial Information	12 Months Ended
	Dec. 31, 2020
Condensed Financial Information Disclosure [Abstract]
Parent-only Financial Information	Parent-only Financial Information The condensed financial statements of Columbia Financial, Inc. (parent company) are presented below: Statements of Financial Condition December 31, 2020 2019 (In thousands) Assets Cash and due from banks $ 94,053 $ 168,242 Short-term investments 170 127 Total cash and cash equivalents 94,223 168,369 Debt securities available for sale, at fair value — 1,496 Equity securities, at fair value 1,167 1,282 Investment in subsidiaries 873,629 785,964 Loan receivable from Bank 41,461 42,982 Other assets 9,803 8,431 Total assets $ 1,020,283 $ 1,008,524 Liabilities and Stockholders' Equity Liabilities: Borrowings $ 6,953 $ 23,831 Accrued expenses and other liabilities 2,043 2,176 Total liabilities 8,996 26,007 Stockholders' equity 1,011,287 982,517 Total liabilities and stockholders' equity $ 1,020,283 $ 1,008,524 (20) Parent-only Financial Information (continued) Statements of Comprehensive Income (Loss) Years Ended December 31, 2020 2019 2018 (In thousands) Dividends from subsidiary $ 50,000 $ 179,000 $ — Interest income: Loans receivable 2,047 2,111 1,513 Debt securities available for sale and equity securities 51 51 123 Interest-earning deposits 1 173 871 Total interest income 52,099 181,335 2,507 Interest expense on borrowings 863 176 3,468 Net interest income (expense) 51,236 181,159 (961) Equity earnings (loss) in subsidiary 8,027 (123,142) 51,401 Non-interest income: Gain on securities transactions 2 236 — Change in fair value of equity securities (115) 65 — Other non-interest income — 139 — Total non-interest income (113) 440 — Non-interest expense: Charitable contribution to foundation — — 34,767 Merger-related expenses 280 1,807 — Other non-interest expense 1,377 1,955 425 Total non-interest expense 1,657 3,762 35,192 Income before income tax benefit 57,493 54,695 15,248 Income tax benefit 110 22 7,488 Net income 57,603 54,717 22,736 Other comprehensive income (loss) (890) 3,710 (6,487) Comprehensive income (loss) $ 56,713 $ 58,427 $ 16,249 (20) Parent-only Financial Information (continued) Statements of Cash Flows Years Ended December 31, 2020 2019 2018 (In thousands) Cash flows from operating activities: Net income $ 57,603 $ 54,717 $ 22,736 Adjustments to reconcile net income to net cash provided by operating activities: Amortization of debt issuance costs — — 890 Amortization of intangible assets (278) (71) — Gain on securities transactions (2) (236) — Change in fair value of equity securities 115 (65) — Deferred tax expense (benefit) 1,411 1,453 (6,086) ( Increase) decrease in other assets (2,675) (2,026) 1,515 (Decrease) increase in accrued expenses and other liabilities (647) 3,515 (1,498) Contribution of common stock to Columbia Bank Foundation — — 34,767 Equity in undistributed (earnings) loss of subsidiary (8,027) 123,142 (51,401) Net cash provided by operating activities $ 47,500 $ 180,429 $ 923 Cash flows from investing activities: Capital contribution to subsidiary $ — $ — $ (246,420) Proceeds from sales of equity securities — 1,065 — Proceeds from paydowns/maturities/calls of debt securities available for sale 1,498 500 1,601 Purchases of debt securities available for sale — — (414) Purchases of equity securities — (416) — Loan to ESOP — — (45,428) Repayment of loan receivable from Bank 1,521 1,457 989 Net cash paid in acquisition — (135,410) — Net cash provided by (used in) investing activities $ 3,019 $ (132,804) $ (289,672) Cash flows from financing activities: Payments of subordinated debt and trust preferred securities $ (16,600) $ — $ (51,547) Issuance of common stock in initial public offering — — 492,428 Purchase of treasury stock (108,166) (55,309) — Issuance of common stock allocated to restricted stock award grants — 21,687 — Restricted stock forfeitures (199) (736) — Repurchase of shares for taxes (181) — — Issuance of treasury stock allocated to restricted stock award grants 481 1,269 — Net cash (used in) provided by financing activities $ (124,665) $ (33,089) $ 440,881 (20) Parent-only Financial Information (continued) Statements of Cash Flows Years Ended December 31, 2020 2019 2018 (In thousands) Net (decrease) increase in cash and cash equivalents $ (74,146) $ 14,536 $ 152,132 Cash and cash equivalents at beginning of year 168,369 153,833 1,701 Cash and cash equivalents at end of period $ 94,223 $ 168,369 $ 153,833 Acquisition: Non-cash assets acquired: Debt securities available for sale $ — $ 1,998 $ — Equity securities — 208 — Other assets — 1,492 — Total non-cash assets acquired $ — $ 3,698 $ — Liabilities assumed: Borrowings $ — $ 23,901 $ — Total liabilities assumed $ — $ 23,901 $ — Net non-cash liabilities acquired $ — $ (20,203) $ — Net cash and cash equivalents acquired in acquisitions $ — $ 884 $ —

Other Comprehensive Income (Los

Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Other Comprehensive Income (Loss)	Other Comprehensive Income (Loss) The following tables present the components of other comprehensive income (loss), both gross and net of tax, for the years ended December 31, 2020, 2019, and 2018: For the Years Ended December 31, 2020 2019 Before Tax Tax Effect After Tax Before Tax Tax Effect After Tax (In thousands) Components of other comprehensive income (loss): Unrealized gains on debt securities available for sale: $ 26,876 $ (5,640) $ 21,236 $ 26,601 $ (5,534) $ 21,067 Accretion of unrealized gain on debt securities reclassified as held to maturity 160 (34) 126 11 (2) 9 Reclassification adjustment for gains included in net income 370 (81) 289 2,612 (601) 2,011 27,406 (5,755) 21,651 29,224 (6,137) 23,087 Derivatives: Unrealized (loss) on swap contracts accounted for as cash flow hedges (10,605) 2,223 (8,382) (8,193) 1,725 (6,468) Employee benefit plans: Amortization of prior service cost included in net income (56) 12 (44) (56) 12 (44) Reclassification adjustment of actuarial net (loss) included in net income (4,284) 900 (3,384) (3,709) 779 (2,930) Change in funded status of retirement obligations (13,583) 2,852 (10,731) (12,576) 2,641 (9,935) (17,923) 3,764 (14,159) (16,341) 3,432 (12,909) Total other comprehensive (loss) income $ (1,122) $ 232 $ (890) $ 4,690 $ (980) $ 3,710 (21) Other Comprehensive Income (Loss) (continued) For the Year Ended December 31, 2018 Before Tax Tax Effect After Tax (In thousands) Components of other comprehensive(loss) income: Unrealized (losses) on debt securities available for sale: $ (7,224) $ 1,446 $ (5,778) Accretion of unrealized (loss) on debt securities reclassified as held to maturity (13) — (13) Reclassification adjustment for (losses) included in net income (116) 24 (92) (7,353) 1,470 (5,883) Derivatives: Unrealized (loss)on swap contracts accounted for as cash flow hedges (2,825) 595 (2,230) Employee benefit plans: Amortization of prior service cost included in net income (623) 132 (491) Reclassification adjustment of actuarial net loss included in net income 2,526 (530) 1,996 Change in funded status of retirement obligations 897 (776) 121 2,800 (1,174) 1,626 Total other comprehensive (loss) income $ (7,378) $ 891 $ (6,487) (21) Other Comprehensive Income (Loss) (continued) The following tables present the changes in the components of accumulated other comprehensive income (loss), net of tax, for the years ended December 31, 2020, 2019, and 2018: For the Years Ended December 31, 2020 2019 Unrealized Gains on Debt Securities Available for Sale Unrealized (Losses) on Swaps Employee Benefit Plans Accumulated Other Comprehensive (Loss) Unrealized (Losses) Gains on Debt Securities Available for Sale Unrealized (Losses) on Swaps Employee Benefit Plans Accumulated Other Comprehensive (Loss) (In thousands) Balance at beginning of period $ 9,377 $ (8,474) $ (69,638) $ (68,735) $ (13,162) $ (2,006) $ (56,729) $ (71,897) Effect of the adoption of ASU 2016-01 — — (548) — — (548) Balance at January 1, $ 9,377 $ (8,474) $ (69,638) $ (68,735) $ (13,710) $ (2,006) $ (56,729) $ (72,445) Current period changes in other comprehensive income (loss) 21,651 (8,382) (14,159) (890) 23,087 (6,468) (12,909) 3,710 Total other comprehensive income (loss) $ 31,028 $ (16,856) $ (83,797) $ (69,625) $ 9,377 $ (8,474) $ (69,638) $ (68,735) For the Year Ended December 31, 2018 Unrealized (Losses) on Debt Securities Available for Sale Unrealized Gains (Losses) on Swaps Employee Benefit Plans Accumulated Other Comprehensive (Loss) (In thousands) Balance at beginning of period $ (7,279) $ 224 $ (58,355) $ (65,410) Current period changes in other comprehensive (loss) income (5,883) (2,230) 1,626 (6,487) Total other comprehensive (loss) $ (13,162) $ (2,006) $ (56,729) $ (71,897) (21) Other Comprehensive Income (Loss) (continued) The following tables reflect amounts reclassified from accumulated other comprehensive income (loss) in the Consolidated Statements of Income and the affected line item in the statement where net income is presented for the years ended December 31, 2020, 2019, and 2018: Accumulated Other Comprehensive (Loss) Income Components For the Years Ended December 31, Affected line items in the Consolidated Statements of Income 2020 2019 2018 (In thousands) Reclassification adjustment for gains (losses) included in net income $ 370 $ 2,612 $ (116) Gain (loss) on securities transactions Reclassification adjustment of actuarial net (loss) gain included in net income (4,284) (3,709) 2,526 Other non-interest expense Total before tax (3,914) (1,097) 2,410 Income (tax) benefit 819 178 (506) Net of tax $ (3,095) $ (919) $ 1,904

Derivatives and Hedging Activit

Derivatives and Hedging Activities	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging Activities	Derivatives and Hedging Activities The Company uses derivative financial instruments as components of its market risk management, principally to manage interest rate risk. Certain derivatives are entered into in connection with transactions with commercial customers. Derivatives are not used for speculative purposes. All derivatives are recognized as either assets or liabilities in the Consolidated Statements of Financial Condition, reported at fair value and presented on a gross basis. Until a derivative is settled, a favorable change in fair value results in an unrealized gain that is recognized as an asset, while an unfavorable change in fair value results in an unrealized loss that is recognized as a liability. The Company generally applies hedge accounting to its derivatives used for market risk management purposes. Hedge accounting is permitted only if specific criteria are met, including a requirement that a highly effective relationship exists between the derivative instrument and the hedged item, both at inception of the hedge and on an ongoing basis. Changes in the fair value of effective fair value hedges are recognized in current earnings (with the change in fair value of the hedged asset or liability also recognized in earnings). Changes in the fair value of effective cash flow hedges are recognized in other comprehensive income (loss) until earnings are affected by the variability in cash flows of the designated hedged item. Ineffective portions of hedge results are recognized in current earnings. Changes in the fair value of derivatives for which hedge accounting is not applied are recognized in current earnings. The Company formally documents at inception all relationships between the derivative instruments and the hedged items, as well as its risk management objectives and strategies for undertaking the hedge transactions. This process includes linking all derivatives that are designated as hedges to specific assets and liabilities, or to specific firm commitments. The Company also formally assesses, both at inception of the hedge and on an ongoing basis, whether the derivatives that are used in hedging transactions are highly effective in offsetting changes in the fair values or cash flows of the hedged items. If it is determined that a derivative is not highly effective or has ceased to be a highly effective hedge, the Company would discontinue hedge accounting prospectively. Gains or losses resulting from the termination of a derivative accounted for as a cash flow hedge remain in other comprehensive income (loss) and is (accreted) amortized to earnings over the remaining period of the former hedging relationship. Certain derivative financial instruments are offered to certain commercial banking customers to manage their risk of exposure and risk management strategies. These derivative instruments consist primarily of currency forward contracts and interest rate swap contracts. The risks associated with these transactions is mitigated by simultaneously entering into similar transactions having essentially offsetting terms with a third party. In addition, the Company executes interest rate swaps with third parties in order to hedge the interest rate risk of short-term FHLB advances. Currency Forward Contracts. At December 31, 2020 and 2019, the Company had no currency forward contracts in place with commercial banking customers. Interest Rate Swaps. At December 31, 2020, the Company had interest rate swaps in place with 48 commercial banking customers executed by offsetting interest rate swaps with third parties, with an aggregated notional amount of $175.1 million. At December 31, 2019, the Company had interest rate swaps in place with 22 commercial banking customers executed by offsetting interest rate swaps with third parties, with an aggregated notional amount of $169.9 million. These derivatives are not designated as hedges and are not speculative. These interest rate swaps do not meet hedge accounting requirements. At December 31, 2020 and 2019, the Company had 31 and 29 interest rate swaps with notional amounts of $430.0 million and $410.0 million, respectively, hedging certain FHLB advances. These interest rate swaps meet the hedge accounting requirements. Interest rate swaps designated as cash flow hedges involve the receipt of variable amounts from counter-party in exchange for the Company making fixed-rate payments over the life of the agreements without the exchanges of the underlying notional amount. For the years ended December 31, 2020, 2019, and 2018, the Company did not record any hedge ineffectiveness associated with these contracts. (22) Derivatives and Hedging Activities (continued) The tables below present the fair value of the Company’s derivative financial instruments as well as their classification in the Consolidated Statements of Financial Condition at December 31, 2020 and 2019: December 31, 2020 Asset Derivative Liability Derivative Consolidated Statements of Financial Condition Fair Value Consolidated Statements of Financial Condition Fair Value (In thousands) Derivatives: Interest rate swaps Other Assets $ 19,425 Other Liabilities $ 42,384 Total derivative instruments $ 19,425 $ 42,384 December 31, 2019 Asset Derivative Liability Derivative Consolidated Statements of Financial Condition Fair Value Consolidated Statements of Financial Condition Fair Value (In thousands) Derivatives: Interest rate swaps Other Assets $ 185 Other Liabilities $ 11,546 Total derivative instruments $ 185 $ 11,546 For the years ended December 31, 2020, 2019, and 2018 losses/(gains) of $306,000, $204,000, and $(52,000) respectively, were recorded for changes in fair value of interest rate swaps with third parties. At December 31, 2020 and 2019, accrued interest was $1.0 million and $344,000, respectively. The Company has agreements with counterparties that contain a provision that if the Company defaults on any of its indebtedness, including default where repayment of the indebtedness has not been accelerated by the lender, then the Company could also be declared in default of its derivative obligations.

Revenue Recognition

Revenue Recognition	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Revenue Recognition	Revenue Recognition On January 1, 2019, the Company adopted ASU 2014-09 Revenue from Contracts with Customers (Topic 606) and all subsequent ASUs that modified Topic 606. The Company performed a review and assessment of all revenue streams, the related contracts with customers, and the underlying performance obligations in those contracts. This guidance does not apply to revenue associated with financial instruments, including interest income on loans and securities, which comprise the majority of the Company's revenue. Revenue-generating activities that are within the scope of Topic 606, are components of non-interest income. These revenue streams can generally be classified as demand deposit account fees, title insurance fees and other fees. The Company, using a modified retrospective transition approach, determined that there was no cumulative effect adjustment to retained earnings as a result of adopting the new standard, nor did the standard have a material impact on our consolidated financial statements including the timing or amounts of revenue recognized. The following table presents non-interest income, segregated by revenue streams in-scope and out-of-scope of Topic 606, for the years ended December 31, 2020, 2019, and 2018. For the Years Ended December 31, 2020 2019 2018 (In thousands) Non-interest income In-scope of Topic 606: Demand deposit account fees $ 3,633 $ 4,478 $ 3,987 Title insurance fees 5,034 4,981 4,297 Other non-interest income 6,472 4,844 4,679 Total in-scope non-interest income 15,139 14,303 12,963 Total out-of-scope non-interest income 16,131 17,333 8,725 Total non-interest income $ 31,270 $ 31,636 $ 21,688 Demand deposit account fees include monthly maintenance fees and service charges. These fees are generally derived as a result of either transaction-based or serviced-based services. The Company's performance obligation for these services is generally satisfied, and revenue recognized, at the time the transaction is completed or the service rendered. Fees for these services are generally received from the customer either at the time of the transaction or monthly. Title insurance fees are generally recognized at the time the transaction closes or when the service is rendered. Other non-interest income includes check printing fees, traveler's check fees, gift card fees, branch service fees, overdraft fees, account analysis fees, other deposit related fees, wealth management related fee income which includes annuity fees, brokerage commissions, and asset management fees. Wealth management related fee income represent fees earned from customers as consideration for asset management and investment advisory services provided by a third party. The Company's performance obligation is generally satisfied monthly and the resulting fees are recognized monthly based upon the month-end market value of the assets under management and the applicable fee rate. The Company does not earn performance-based incentives. The Company's performance obligation for these transaction-based services are generally satisfied, and related revenue recognized, at the time the transaction closes or when the service is rendered or a point in time when the service is completed. Also included in other fees are debit card and ATM fees which are transaction-based. Debit card revenue is primarily comprised of interchange fees earned when a customer's Company card is processed through a card payment network. ATM fees are largely generated when a Company cardholder uses a non-Company ATM, or a non-Company cardholder uses a Company ATM. The Company's performance obligation for these services is satisfied when the service is rendered. Payment is generally received at time of transaction or monthly. Out-of-scope non-interest income primarily consists of income from bank-owned life insurance, loan prepayment and servicing fees, net fees loan level swaps, gains and losses on the sale of loans and securities, and changes in the fair value of equity securities. None of these revenue streams are subject to the requirements of Topic 606.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events The Company has evaluated events subsequent to December 31, 2020 and through the financial statement issuance date of March 1, 2021. The Company has not identified any material subsequent events that would require adjustment or disclosure in the consolidated financial statements. The COVID-19 pandemic has disrupted and adversely affected the Bank's business and results of operations, and the ultimate impacts of the pandemic on the Bank's business, financial condition and results of operations will depend on future developments and other factors that are highly uncertain and will be impacted by the scope and duration of the pandemic and actions taken by governmental authorities in response to the pandemic.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Principles of Consolidation	Principles of Consolidation The accompanying consolidated financial statements include the accounts of Columbia Financial, Inc., its wholly-owned subsidiary, Columbia Bank (the "Bank") and the Bank's wholly-owned subsidiaries, Columbia Investment Services, Inc., 2500 Broadway Corp. 1901 Residential Management Co. LLC, Plaza Financial Services, Inc., First Jersey Title Services, Inc., Real Estate Management Corp. LLC, 1901 Commercial Management Co. LLC, Stewardship Realty LLC, and CSB Realty Corp. (collectively, the “Company”). In consolidation, all intercompany accounts and transactions are eliminated. Certain reclassifications have been made in the consolidated financial statements to conform with current year classifications. During the year ended December 31, 2020, the Company revised the Consolidated Statements of Cash Flows for the years ended December 31, 2019 and 2018. The revision consisted of reclassifying the proceeds from sales of loans held-for-sale from cash flows from operating activities to cash flows from investing activities. The impact of these revisions was a decrease to cash flows from operating activities and an increase to cash flows from investing activities of $101.9 million and $3.6 million for the years ended December 31, 2019 and 2018, respectively. The revisions had no impact on cash and cash equivalents as of December 31, 2019 and 2018. The Company also owned 100% of the common stock of Columbia Financial Capital Trust I (the "Trust"). The Trust was used to issue trust preferred securities. In accordance with Accounting Standards Codification ("ASC") Topic 810, Consolidation , the Trust was classified as a variable interest entity and did not satisfy the conditions for consolidation. Accordingly, the Trust was treated as an unconsolidated subsidiary. In August 2018, the Company redeemed, in full $51.5 million of junior subordinated debt securities, which represented 100% of the assets of the Trust. The Bank's wholly owned subsidiary, Stewardship Realty, LLC, incorporated as a New Jersey corporation in 2005 was acquired in the Company's merger with Stewardship in November 2019. It is a service corporation originally organized to hold and manage property in Midland Park which was previously occupied by Atlantic Stewardship Bank. The Company also owns 100% of the common stock of Stewardship Statutory Trust I, which is a trust incorporated in Delaware which was also acquired in the Company's merger with Stewardship in November 2019. In accordance with ASC Topic 810, Consolidation
Basis of Financial Statement Presentation	Basis of Financial Statement Presentation The consolidated financial statements of the Company have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). In preparing the consolidated financial statements, management is required to make estimates and assumptions about future events. These estimates and the underlying assumptions affect the reported amounts of assets and liabilities and disclosures about contingent assets and liabilities as of the dates of the Consolidated Statements of Financial Condition, and Consolidated Statements of Income for the periods presented. Material estimates that are particularly susceptible to change are the determination of the adequacy of the allowance for credit losses, evaluation of goodwill for impairment, evaluation of other-than-temporary impairment on securities, evaluation of the need for valuation allowances on deferred tax assets, and determination of liabilities related to retirement and other post-retirement benefits, among others. These estimates and assumptions are based on management’s best estimates and judgment. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment, which management believes to be reasonable under the circumstances. Such estimates and assumptions are adjusted when facts and circumstances dictate. Illiquid credit markets, volatile securities markets, and declines in the housing market and the economy generally have combined to increase the uncertainty inherent in such estimates and assumptions. As future events and their effects cannot be determined with precision, actual results could differ significantly from these estimates. Changes in estimates resulting from continuing changes in the economic environment will be reflected in the consolidated financial statements in future periods.
Cash and Cash Equivalents	Cash and Cash Equivalents    Cash and cash equivalents include cash on hand, amounts due from banks and interest-bearing deposits at other financial institutions and short-term investments. The Company is required by the Federal Reserve Bank System to maintain cash reserves equal to a percentage of certain deposits.
Securities	Securities Securities are classified as available for sale and held to maturity. Management determines the appropriate classification of securities at the time of purchase. Securities that management has the positive intent and ability to hold to maturity are classified as held to maturity and reported at amortized cost. Securities not classified as held to maturity are classified as available for sale and carried at estimated fair value, with unrealized holding gains or losses, net of taxes, reported as a separate component of accumulated other comprehensive income or loss ("OCI") included in stockholders' equity. The fair values of these securities are based on market quotations or matrix pricing as discussed in note 17. The Company evaluates securities for other-than-temporary impairment at each reporting period and more frequently when economic or market conditions warrant such evaluation. In this evaluation, if such declines were deemed other-than temporary, management would measure the total credit-related component of the unrealized loss, and recognize that portion of the loss as a charge to current period earnings. The remaining portion of the unrealized loss would be recognized as an adjustment to OCI. The fair value of the securities portfolio is significantly affected by changes in interest rates. In general, as interest rates rise, the fair value of fixed-rate securities decreases and as interest rates fall, the fair value of fixed-rate securities increases. The Company determines if it has the intent to sell securities or if it more likely than not that the Company would be required to sell the securities before the anticipated recovery. If either exists, the decline in value is considered other-than-temporary and would be recognized in current period earnings. Premiums and discounts on securities are generally amortized and accreted to income over the contractual lives of the securities using the level-yield method. Premiums on callable securities are amortized to the earliest call date. Dividend and interest income are recognized when earned. Realized gains and losses are recognized when securities are sold or called based on the specific identification method. In the ordinary course of business, securities are pledged as collateral in conjunction with the Company’s borrowings, lines of credit, and public funds on deposit.
Federal Home Loan Bank Stock	Federal Home Loan Bank Stock The Bank, as a member of the Federal Home Loan Bank of New York (the "FHLB"), is required to hold shares of capital stock of the FHLB based on its activities, primarily its outstanding borrowings. The Bank carries the investment at cost, or par value, which approximates fair value. Cash dividends are reported as income.
Loans Held-for-Sale	Loans Held-for-Sale    Loans held-for-sale consists of loans intended for sale in the secondary market. These loans are carried at the lower of cost or estimated fair value, less costs to sell, as determined on an individual loan basis. Net unrealized losses, if any, are recognized in a valuation allowance through a charge to earnings. Origination fees and costs on loans held-for-sale are deferred and recognized on settlement dates as a component of the gain or loss on sale. Loans held-for-sale are generally sold with loan servicing rights retained by the Bank.
Loans Receivable	Loans Receivable Loans receivable are carried at unpaid principal balances adjusted by unamortized premiums and unearned discounts, net deferred origination fees and costs less the allowance for loan losses. The Bank defers loan origination fees and certain direct loan origination costs and accretes such amounts as an adjustment to the yield over the expected lives of the related loans using the level-yield method. Interest income on loans is accrued and credited to income as earned. Premiums and discounts on loans purchased are amortized or accreted as an adjustment to yield over the contractual lives of the related loans using methodologies which approximate the level-yield method. A loan is considered delinquent when payment has not been received within 30 days of its contractual due date. Generally, a loan in designated as a non-accrual loan when the payment of interest is 90 days or more in arrears of its contractual due date. When a loan is placed on non-accrual status, any interest accrued but not received is reversed against interest income. Payments received on a non-accrual loan are either applied to the outstanding principal balance or recorded as interest income, depending on an assessment of the ability to collect the loan. Non-accruing loans are returned to accrual status after there has been a sustained period of repayment performance (generally six consecutive months of payment) and both principal and interest are deemed collectible. The Company identifies loans which may need to be charged-off as a loss, by reviewing all delinquent loans, classified loans and other loans that management may have concerns about collectability.
Purchased Credit-Impaired ("PCI") Loans	Purchased Credit-Impaired ("PCI") Loans Purchased credit impaired loans are loans acquired through acquisitions at a discount primarily due to deteriorated credit quality. PCI loans are recorded at fair value at the date of acquisition, based upon the present value of expected future cash flows, with no carryover of the related allowance for credit losses. Determining the fair value of the loans involves projecting the amount and timing of principal and/or interest cash flows expected to be collected on the loans discounting those cash flows at a market rate of interest. The excess of cash flows expected at acquisition over the estimated fair value is referred to as the accretable yield and is recognized into interest income over the remaining life of the loan. The difference between contractually required payments at acquisition and the cash flows expected to be collected at acquisition is referred to as the nonaccretable yield. The nonaccretable yield represents estimated future credit losses expected to be incurred over the life of the loan. Subsequent decreases to the expected cash flows require us to evaluate the need for an allowance for credit losses. Subsequent improvements in expected cash flows result in the reversal of a corresponding amount of the nonacretable yield which we then reclassify as accretable yield that is recognized into interest income over the remaining life of the loan using the interest method. The evaluation of the amount of future cash flows that is expected to be collected is performed in a similar manner used to determine the allowance for loan losses. Any charge-offs of principal on acquired loans would first be applied against the nonaccretable yield portion of the fair value adjustment.
Allowance for Loan Losses	Allowance for Loan Losses Losses on loans are charged to the allowance for loan losses. Additions to this allowance are made by recoveries of loans previously charged off and by a provision charged to expense. The determination of the balance of the allowance for loan losses is based on an analysis of the loan portfolio, economic conditions, historical loan loss experience and other factors that warrant recognition in providing an adequate allowance. Estimates and judgments required to establish the allowance include: overall economic environment; value of collateral; strength of guarantors; loss exposure in the event of default; the amount and timing of future cash flows on impaired loans; and determination of loss factors applied to the portfolio segments. These estimates are susceptible to significant change. Management regularly reviews loss experience within the portfolio and monitors current economic conditions and other factors related to the collectability of the loan portfolio. While management uses available information, future additions to the allowance may be necessary based on changes in economic conditions in the Bank's market area. In addition, regulatory agencies, as an integral part of their examination process, periodically review the adequacy of the Bank's allowance for loan losses as an integral part of their examination. Such agencies may require the Bank to recognize additions to the allowance or additional write-downs based on their judgments about information available to them at the time of their examination. Although management uses the best information available, the level of the allowance for loan losses remains an estimate that is subject to significant uncertainties.
Troubled Debt Restructuring	Troubled Debt Restructuring Troubled debt restructured loans are those loans where the Company has granted a concession it would not otherwise consider because of economic or legal reasons pertaining to a debtor’s financial difficulties. A concession could include a reduced interest rate below a market rate, an extension of the term of the loan, or a combination of the two methods, but generally does not result in the forgiveness of principal or accrued interest. Not all concessions granted by the Company constitute a troubled debt restructuring. Once an obligation has been restructured and designated as a troubled debt restructuring, it continues to be designed as a restructured loan until paid in full. The Company records an impairment charge equal to the difference between the present value of expected future cash flows under the restructured terms discounted at the loan’s original effective interest rate, and the loan’s carrying value. Changes in the calculated impairment due to the passage of time are recorded as an adjustment to the allowance for loan losses. Restructured loans that were accruing prior to the restructuring, where income was reasonably assured subsequent to the restructuring, maintain their accrual status. Restructured loans for which collectability was not reasonably assured are placed on non-accrual status, interest accruals cease, and uncollected accrued interest is reversed and charged against current income. Non-accruing restructured loans may be returned to accrual status when there is a sustained period of repayment performance (generally six consecutive months of payments), and both principal and interest are deemed collectible.
Loans Sold and Serviced	Loans Sold and Serviced The Company has entered into Guarantor Swaps with Freddie Mac to improve its liquidity. In these types of transactions, the Company sells mortgage loans in exchange for Freddie Mac Mortgage Participation Certificates backed exclusively by the loans sold. The Company retains the servicing of these loans. The Company also periodically sells loans to investors and continues to service such loans for a fee. Gains or losses on the sale of loans are recorded on trade date using the specific-identification method.
Office Properties and Equipment	Office Properties and Equipment    Land is carried at cost. Office properties, land and building improvements, furniture and equipment, and leasehold improvements are carried at cost, less accumulated depreciation and amortization. Depreciation and amortization of office properties and equipment is computed on a straight-line basis over their estimated useful lives (generally 40 years for buildings, 10 years to 20 years for land and building improvements, 3 years to 10 years for furniture and equipment). Leasehold improvements, carried at cost, net of accumulated depreciation, are amortized over the terms of the related leases or the estimated useful lives of the assets, whichever is shorter. Major improvements are capitalized, while repairs and maintenance costs are charged to expense as incurred. Upon retirement or sale, any gain or loss is recognized as incurred.
Bank-owned Life Insurance	Bank-owned Life Insurance ("BOLI")    Bank-owned life insurance is accounted for using the cash surrender value method and is recorded at its net realizable value. The change in the net asset value is recorded as a component of non-interest income. A deferred liability has been recorded for the estimated cost of post-retirement life insurance benefits accruing to applicable employees and directors covered by an endorsement split-dollar life insurance arrangement.
Goodwill and Intangible Assets	Goodwill and Intangible Assets Intangible assets of the Bank consist of goodwill, core deposit intangibles and mortgage servicing rights. Goodwill represents the excess of the purchase price over the fair value of net assets acquired in purchase acquisitions. In accordance with GAAP, goodwill with an indefinite useful life is not amortized, but is evaluated for impairment on an annual basis, or more frequently if events or changes in circumstances indicate potential impairment between annual measurement dates. As permitted by GAAP, the Company prepares a qualitative assessment in determining whether goodwill may be impaired. The factors considered in the assessment include macroeconomic conditions, industry and market conditions and overall financial performance of the Company, among others. The Company completed its annual goodwill impairment test as of December 31, 2020 based upon its qualitative assessment of goodwill and concluded that goodwill was not impaired and no further quantitative analysis was warranted. Core deposit intangibles represent the balance of the core deposit intangibles ascribed to the value of deposits acquired by the Bank through the acquisition of Stewardship. Mortgage servicing rights are recorded when purchased or when originated mortgage loans are sold, with servicing rights retained. Mortgage servicing rights are amortized on an accelerated method based upon the estimated lives of the related loans, and generally adjusted for prepayments. Mortgage servicing rights are carried at the lower of amortized cost or fair value.
Leases	Leases The Company determines if an arrangement is a lease at inception. The Company's leases primarily relate to real estate property for branches and office space. All the Company's leases are classified as operating leases and the related right-of-use asset ("ROU") and lease liability are included in other assets other liabilities ROU assets represent the Company’s right to use an underlying asset for the lease term, and lease liabilities represent the Company’s obligation to make lease payments arising from the lease arrangements. The calculated amounts of the ROU asset and lease liabilities are impacted by the length of the lease term and the discount rate used to calculate the present value of minimum lease payments. As the Company's leases do not provide an implicit rate, the discount rate used in determining the lease liability for each individual lease is the Company's incremental borrowing rate. The present value of the lease liability may include the impact of options to extend or terminate the lease when it is reasonably certain that the Company will exercise such options provided in the lease terms. Lease expense is recognized on a straight-line basis over the expected lease term. Lease agreements that include lease and non-lease components, such as common area maintenance charges, are accounted for separately.
Post-retirement Benefits	Post-retirement Benefits The Company provides certain health care and life insurance benefits to eligible retired employees under a Post-retirement Plan, along with a split-dollar BOLI death benefit. The Company accrues the cost of retiree health care and other benefits during the employees’ period of active service. Effective January 1, 2019, the Post-retirement plan has been closed to new hires. Effective January 1, 2019, the Company implemented ASU 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Post-retirement Benefit Cost. Under this ASU, the FASB requires employers to report the service cost component in the same line item as other compensation costs arising from services rendered by the pertinent employees during the period. The other components of net periodic benefit cost are required to be presented in the Consolidated Statements of Income separately from the service cost component. This ASU is also required to be applied retrospectively to all periods presented.
Employee Benefits Plans	Employee Benefit Plans The Company maintains a single-employer tax-qualified defined benefit pension plan (the "Pension Plan") which covers full-time employees that satisfy the Pension Plan eligibility requirements. Effective October 1, 2018, employees hired by the Bank are not eligible to participate in the Company's Pension Plan as the plan has been closed to new employees as of that date. The Company's policy is to fund at least the minimum contribution required by the Employee Retirement Income Security Act of 1974. GAAP requires an employer to: (a) recognize in its statement of financial position the over-funded or under-funded status of a defined benefit post-retirement plan measured as the difference between the fair value of plan assets and the benefit obligation; (b) measure a plan’s assets and its obligations that determine its funded status at the end of the employer’s fiscal year (with limited exceptions); and (c) recognize as a component of other comprehensive income (loss), net of tax, the actuarial gains and losses and the prior service costs and credits that arise during the period. The assets of the plan are primarily invested in fixed income and equity funds. The Company has a retirement income maintenance plan (the "RIM Plan") which is a non-qualified defined benefit plan which provides benefits to all employees of the Company if their benefits under the Pension Plan are limited by the Internal Revenue Code. The Company has a 401(k) plan covering substantially all employees of the Company. The Company may match a percentage of the first 3.00% to 4.50% contributed by participants. The Company's matching contribution, if any, is determined by the Board of Directors in its sole discretion. The Company has an Employee Stock Ownership Plan ("ESOP"). The funds borrowed by the ESOP from the Company to purchase the Company's common stock are being repaid from the Bank's contributions over a period of 20 years. The Company's common stock not allocated to participants is recorded as a reduction of stockholders' equity at cost. Compensation expense for the ESOP is based on the average price of the Company's stock and the amount of shares committed to be allocated during each period. The Company has a Supplemental Executive Retirement Plan ("SERP"). The SERP is a non-qualified plan which provides supplemental retirement benefits to eligible officers (those designated by the Board of Directors) of the Company who are prevented from receiving the full benefits contemplated by the ESOP's benefit formulas under tax law limits for tax-qualified plans. In addition, the Company maintains a stock based deferral plan (the "Stock Based Deferral Plan") for certain executives and directors. The Company records a deferred compensation equity account and corresponding contra-equity account for the cost of the shares held by the Stock Based Deferral and SERP Plans.
Derivatives	Derivatives The Company uses derivative financial instruments as components of its market risk management, principally to manage interest rate risk. Certain derivatives are entered into in connection with transactions with commercial customers. Derivatives are not used for speculative purposes. All derivatives are recognized as either assets or liabilities in the Consolidated Statements of Financial Condition, reported at fair value and presented on a gross basis. Until a derivative is settled, a favorable change in fair value results in an unrealized gain that is recognized as an asset, while an unfavorable change in fair value results in an unrealized loss that is recognized as a liability. The Company generally applies hedge accounting to its derivatives used for market risk management purposes. Hedge accounting is permitted only if specific criteria are met, including a requirement that a highly effective relationship exists between the derivative instrument and the hedged item, both at inception of the hedge and on an ongoing basis. Changes in the fair value of effective fair value hedges are recognized in current earnings (with the change in fair value of the hedged asset or liability also recognized in earnings). Changes in the fair value of effective cash flow hedges are recognized in other comprehensive income (loss) until earnings are affected by the variability in cash flows of the designated hedged item. Ineffective portions of hedge results are recognized in current earnings. Changes in the fair value of derivatives for which hedge accounting is not applied are recognized in current earnings. The Company formally documents at inception all relationships between the derivative instruments and the hedged items, as well as its risk management objectives and strategies for undertaking the hedge transactions. This process includes linking all derivatives that are designated as hedges to specific assets and liabilities, or to specific firm commitments. The Company also formally assesses, both at inception of the hedge and on an ongoing basis, whether the derivatives that are used in hedging transactions are highly effective in offsetting changes in the fair values or cash flows of the hedged items. If it is determined that a derivative is not highly effective or has ceased to be a highly effective hedge, the Company would discontinue hedge accounting prospectively. Gains or losses resulting from the termination of a derivative accounted for as a cash flow hedge remain in other comprehensive income (loss) and is (accreted) amortized to earnings over the remaining period of the former hedging relationship. Certain derivative financial instruments are offered to certain commercial banking customers to manage their risk of exposure and risk management strategies. These derivative instruments consist primarily of currency forward contracts and interest rate swap contracts. The risks associated with these transactions is mitigated by simultaneously entering into similar transactions having essentially offsetting terms with a third party. In addition, the Company executes interest rate swaps with third parties in order to hedge the interest rate risk of short-term FHLB advances.
Income Taxes	Income Taxes The Company and its subsidiaries file consolidated federal income tax returns. Federal income taxes are allocated to each entity based on their respective contributions to taxable income of the consolidated income tax returns. Beginning in 2019 as required by the State of New Jersey, the Company adopted combined income tax reporting for certain members of a commonly-controlled unitary business group. Prior to 2019, separate state income tax returns were filed for the Company and each of its qualifying subsidiaries. The Company records income taxes in accordance with ASC Topic 740, Income Taxes , using the asset and liability method. The amounts reflected on the Company's federal and state income tax returns differ from these provisions due principally to temporary differences in the reporting of certain items for consolidated financial statement reporting and income tax reporting purposes. Accordingly, deferred tax assets and liabilities: (i) are recognized for the expected future tax consequences of events that have been recognized in the financial statements or tax returns; (ii) are attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases; and (iii) are measured using enacted tax rates expected to apply in the years when those temporary differences are expected to be recovered or settled. Where applicable, deferred tax assets are reduced by a valuation allowance for any portions determined not likely to be realized. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income tax expense in the period that includes the enactment date. The valuation allowance is adjusted, by a charge or credit to income tax expense, as changes in facts and circumstances warrant. The Company did not have any liabilities for uncertain tax positions or any known unrecognized tax benefits at December 31, 2020 and 2019. The Company recognizes interest and penalties related to unrecognized tax benefits in income tax expense in the Consolidated Statements of Income. The Company did not recognize any interest and penalties during the years ended December 31, 2020, 2019 and 2018. (2) Summary of Significant Accounting Policies (continued) Income Taxes (continued) On July 1, 2018, New Jersey enacted legislation which adds to the state’s 9.0% Corporation Business Tax rate (i) a 2.5% surtax for periods beginning in 2018 and 2019 and (ii) a 1.5% surtax for periods beginning in 2020 and 2021. Subsequently, on September 12, 2020, New Jersey enacted legislation that restored and extended the 2.5% Corporation Business Tax surcharge to apply retroactively from January 1, 2020 through December 31, 2023. These surtaxes apply to corporations with more than $1.0 million of net income allocated to New Jersey. In addition, for periods beginning in 2019, as previously noted, New Jersey adopted combined income tax reporting for certain members of a commonly-controlled unitary business group, and issued guidance in December 2019 to clarify business entities to be included and excluded from this combined group.
Comprehensive Income (Loss)	Comprehensive Income (Loss) Comprehensive income (loss) consists of net income and other comprehensive income (loss). Other comprehensive income (loss) includes items recorded in equity, such as unrealized gains and losses on debt securities available for sale, the noncredit component of other than temporary impairment losses on debt securities, unrealized gains and losses on derivatives, and the unfunded status and reclassification of actuarial net (loss) gain associated with the Company's benefit plans. Comprehensive income is presented in a separate Consolidated Statement of Comprehensive Income (Loss).
Segment Reporting	Segment Reporting The Company’s operations are substantially in the financial services industry and include providing traditional banking and other financial services to its customers. The Company operates primarily in New Jersey. Management makes operating decisions and assesses performance based on an ongoing review of the Company’s consolidated financial results. Therefore, the Company has a single operating segment for financial reporting purposes.
Earnings Per Share	Earnings Per Share ("EPS") Basic EPS is computed by dividing net income available to common shareholders by the weighted average number of common shares outstanding during the period. For purposes of calculating basic EPS, weighted average common shares outstanding excludes treasury stock, unallocated employee stock ownership plan shares that have not been committed for release and deferred compensation obligations required to be settled in shares of Company stock.
Stock Compensation Plans	Stock Compensation Plans Compensation expense related to stock options and non-vested restricted stock awards is based on the fair value of the award on the measurement date with expense recognized on a straight line basis over the requisite performance or service period. The fair value of stock options is estimated utilizing the Black-Scholes option pricing model. The fair value of non-vested restricted stock awards is generally the closing market price of the Company's common stock on the date of grant. The Company accounts for forfeitures as they occur.
Recent Accounting Pronouncements	Recent Accounting Pronouncements As an “emerging growth company” as defined in Title 1 of the Jumpstart Our Business Startups (JOBS) Act prior to December 31, 2019, the Company elected to use the extended transition period to delay the adoption of new or reissued accounting pronouncements applicable to public companies until such pronouncements were made applicable to private companies. Accounting Pronouncements Adopted In October 2018, the FASB issued ASU No. 2018-16, Derivatives and Hedging (Topic 815)- Inclusion of the Secured Overnight Financing Rate ("SOFR") Overnight Index Swap ("OIS") Rate as a Benchmark Interest Rate for Hedge Accounting Purposes. This ASU permits the use of the OIS rate based upon SOFR as a U.S. benchmark interest rate for hedge accounting (2) Summary of Significant Accounting Policies (continued) Recent Accounting Pronouncements (cont'd) Accounting Pronouncements Adopted (continued) purposes under Topic 815 in addition to the direct Treasury obligations of the U.S. Government, the LIBOR swap rate, the OIS rate based on the Fed Funds Effective Rate, and the Securities Industry and Financial Markets Association Municipal Swap Rate. The amendments in this ASU are required to be adopted concurrently with the amendments in ASU No. 2017-12, Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities, which was issued in August 2017. The effective date for this ASU for the Company is for fiscal years beginning after December 15, 2019, with early adoption, including adoption in an interim period permitted. The amendments should be adopted on a prospective basis for qualifying new or redesignated hedging relationships entered into on or after date of adoption. The Company adopted this guidance effective January 1, 2020. The adoption of this ASU did not have a material impact on the Company's consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement. The purpose of this updated guidance is to improve the effectiveness and disclosures in the notes to the consolidated financial statements . The ASU removes the requirement to disclose the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy; removes the policy for timing of transfers between levels; and removes the disclosure related to the valuation process for Level 3 fair value measurements. The ASU also modifies existing disclosure requirements which relate to the disclosure for investments in certain entities which calculate net asset value and clarifies the disclosure about uncertainty in the measurements as of the reporting date. For all entities, the effective date for this guidance is fiscal years beginning after December 15, 2019, including interim periods within the reporting period, with early adoption permitted. Entities are also allowed to elect early adoption of the eliminated or modified disclosure requirements and delay adoption of the new disclosure requirements until their effective date. The Company adopted this guidance effective January 1, 2020. The adoption of this ASU did not have a material impact on the Company's consolidated financial statements. In March 2017, the FASB issued ASU No. 2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities. This guidance shortens the amortization period for premiums on callable debt securities by requiring that premiums be amortized to the first (or earliest) call date instead of as an adjustment to the yield over the contractual life. This change more closely aligns the accounting with the economics of a callable debt security and the amortization period with expectations that already are included in market pricing on callable debt securities. This guidance does not change the accounting for discounts on callable debt securities, which will continue to be amortized to the maturity date. This guidance includes only instruments that are held at a premium and have explicit call features. It does not include instruments that contain prepayment features, such as mortgage backed securities; nor does it include call options that are contingent upon future events or in which the timing or amount to be paid is not fixed. The effective date for this ASU for the Company is fiscal years beginning after December 15, 2019, including interim periods within the reporting period, with early adoption permitted. Transition is on a modified retrospective basis with an adjustment to retained earnings as of the beginning of the period of adoption. The Company adopted this guidance effective January 1, 2020. The adoption of this ASU did not have a material impact on the Company's consolidated financial statements. In January 2017, the FASB issued ASU No. 2017-04, Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. The main objective of this guidance is to simplify the accounting for goodwill impairment by requiring that impairment charges be based upon the first step in the current two-step impairment test under ASC 350. Currently, if the fair value of a reporting unit is lower than its carrying amount (Step 1), an entity calculates any impairment charge by comparing the implied fair value of goodwill with its carrying amount (Step 2). The implied fair value of goodwill is calculated by deducting the fair value of all assets and liabilities of the reporting unit from the reporting unit’s fair value as determined in Step 1. To determine the implied fair value of goodwill, entities estimate the fair value of any unrecognized intangible assets and any corporate-level assets or liabilities that were included in the determination of the carrying amount and fair value of the reporting unit in Step 1. Under this guidance, if a reporting unit’s carrying amount exceeds its fair value, an entity will record an impairment charge based on that difference. The impairment charge will be limited to the amount of goodwill allocated to that reporting unit. This guidance eliminates the requirement to calculate a goodwill impairment charge using Step 2. This guidance does not change the guidance on completing Step 1 of the goodwill impairment test. Under this guidance, an entity will still be able to perform the current optional qualitative goodwill impairment assessment before determining whether to proceed to Step 1. The guidance in the ASU was applied prospectively and is effective for the Company for annual and interim impairment tests performed in periods beginning after December 15, 2019. The Company adopted this guidance effective January 1, 2020. The adoption of this ASU did not have a material impact on the Company's consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). This guidance requires all lessees to recognize a lease liability and a right-of-use asset, measured at the present value of the future minimum lease payments, at the lease (2) Summary of Significant Accounting Policies (continued) Recent Accounting Pronouncements (cont'd) Accounting Pronouncements Adopted (continued) commencement date for leases classified as operating leases as well as finance leases. The update also requires new quantitative disclosures related to leases in the Company's consolidated financial statements. There are also practical expedients in this update related to leases that commenced before the effective date, initial direct costs and the use of hindsight to extend or terminate a lease or purchase a leased asset. Lessor accounting remains largely unchanged under this new guidance. In January 2018, the FASB issued ASU 2018-01, Leases (Topic 842)-Land Easement Practical Expedient for Transition to Topic 842 , which provides an optional practical expedient to not evaluate land easements which were existing or expired before the adoption of Topic 842 that were not accounted for as leases under Topic 840. In July 2018, the FASB issued ASU 2018-10, Codification Improvements to Topic 842, Leases and ASU 2018-11, Leases (Topic 842) -Targeted Improvements which provides entities with an optional transition method under which comparative periods presented in the financial statements will continue to be in accordance with current Topic 840, Leases, and a practical expedient to not separate non-lease components from the associated lease component. The guidance is effective for the Company for annual periods beginning after December 15, 2019, including interim periods within that reporting period. In the evaluation of this guidance, the Company identified the inventory of leases and actively accumulated the requisite lease data necessary to apply the guidance. The Company selected a software platform to support the recording, accounting and disclosure requirements of the new lease guidance. Upon adoption, the Company recorded a right-of-use asset and lease liability as of January 1, 2020. See note 9 for more information regarding adoption. In March 2017, the FASB issued ASU No. 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Post-retirement Benefit Cost, which requires that companies disaggregate the service cost component from other components of net benefit cost. This update calls for companies that offer post-retirement benefits to present the service cost, which is the amount an employer has to set aside each quarter or fiscal year to cover the benefits, in the same line item with other current employee compensation costs. Other components of net benefit cost will be presented in the income statement separately from the service costs component and outside the subtotal of income from operations, if one is presented. The effective date for this ASU for the Company is fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The Company adopted this guidance effective January 1, 2019. See note 14 for additional disclosure regarding the impact of adoption of this ASU on the Company's consolidated financial statements. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments, a new standard which addresses diversity in practice related to eight specific cash flow issues: debt prepayment or extinguishment costs, settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing, contingent consideration payments made after a business combination, proceeds from the settlement of insurance claims, proceeds from the settlement of corporate-owned life insurance policies (including bank-owned life insurance policies), distributions received from equity method investees, beneficial interests in securitization transactions and separately identifiable cash flows and application of the predominance principle. This guidance in the ASU is effective for the Company for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Entities will apply the standard’s provisions using a retrospective transition method to each period presented. If it is impracticable to apply the amendments retrospectively for some of the issues, the amendments for those issues would be applied prospectively as of the earliest date practicable. The Company adopted this guidance effective January 1, 2019. The adoption of this ASU did not have a material impact on the Company's consolidated financial statements. In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments- Overall: Recognition and Measurement of Financial Assets and Financial Liabilities. This guidance requires an entity to: (i) measure equity investments at fair value through net income, with certain exceptions; (ii) present in other comprehensive income the changes in instrument-specific credit risk for financial liabilities measured using the fair value option; (iii) present financial assets and financial liabilities by measurement category and form of financial asset; (iv) calculate the fair value of financial instruments for disclosure purposes based on an exit price; and (v) assess a valuation allowance on deferred tax assets related to unrealized losses on available-for-sale debt securities in combination with other deferred tax assets. This guidance provides an election to subsequently measure certain non-marketable equity investments at cost less any impairment and adjusted for certain observable price changes. The guidance also requires a qualitative impairment assessment of such equity investments and amends certain fair value disclosure requirements. The Company adopted this guidance effective January 1, 2019. As a result, $1.9 million of equity securities, as of December 31, 2018, were reclassified from securities available for sale, and presented as a separate line item on the Consolidated Statements of Financial Condition. The $548,000 after tax unrealized gain on these securities, at time of adoption, was reclassified from other comprehensive income (loss) to retained earnings, and is reflected in the consolidated statements of changes in stockholders' equity. For financial instruments that are measured at amortized cost, the Company measures fair value utilizing an exit price methodology. (2) Summary of Significant Accounting Policies (continued) Recent Accounting Pronouncements (cont'd) Accounting Pronouncements Adopted (continued) See note 17 for additional disclosure regarding the impact of adoption of this ASU on the Company's consolidated financial statements. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers. The objective of this amendment is to clarify the principles for recognizing revenue and to develop a common revenue standard for U.S. GAAP. This update affects any entity that either enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of non- financial assets unless those contracts are in the scope of other standards. The guidance in the ASU was effective for the Company for fiscal years beginning after December 15, 2018. Subsequently, the FASB issued various amendments that were intended to improve and clarify the implementation guidance of ASU No. 2014-09 and had the same effective date as the original guidance. The Company's revenue is primarily comprised of net interest income on interest earning assets and liabilities and non-interest income. The scope of guidance explicitly excludes net interest income as well as other revenues associated with financial assets and liabilities, including loans, leases, securities and derivatives. The Company adopted this guidance effective January 1, 2019, after completing an evaluation of the Company's revenue streams and applicable revenue recognition, and concluded that there are no material changes related to the timing or amount of revenue recognition. The adoption of this guidance did not have a significant impact on the Company's consolidated financial statements, but resulted in additional footnote disclosures, including the disaggregation of certain categories of revenues. See note 23 for additional disclosure regarding the impact of adoption of this ASU on the Company's consolidated financial statements.
Fair Value Measurements	Collateral Dependent Impaired Loans Loans which meet certain criteria are evaluated individually for impairment. For loans measured for impairment based on the fair value of the underlying collateral, fair value was estimated using a market approach. The Company measures the fair value of collateral underlying impaired loans primarily through obtaining independent appraisals that rely upon quoted market prices for similar assets in active markets. These appraisals include adjustments, on an individual case-by-case basis, to comparable assets based on the appraisers’ market knowledge and experience, as well as adjustments for estimated costs to sell between 6% and 8%. The Company classifies these loans as Level 3 within the fair value hierarchy. Mortgage Servicing Rights, Net ("MSR"s") Mortgage servicing rights are carried at the lower of cost or estimated fair value. The estimated fair value of MSRs is obtained through an analysis of future cash flows, incorporating assumptions that market participants would use in determining fair value including market discount rates, prepayments speeds, servicing income, servicing costs, default rates and other market driven data, including the market's perception of future interest rate movements. The prepayment speed and the discount rate are considered two of the most significant inputs in the model. A significant degree of judgment is involved in valuing the mortgage servicing rights using Level 3 inputs. The use of different assumptions could have a significant effect on this fair value estimate.

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
Schedule of recognized identified assets acquired and liabilities assumed	The following table sets forth assets acquired and liabilities assumed in the Stewardship acquisition, at their estimated fair values as of the closing date of the transaction: November 1, 2019 Assets acquired: Cash and cash equivalents $ 105,006 Debt securities available for sale 51,710 Equity securities 1,073 Federal Home Loan Bank stock 3,716 Loans receivable 757,223 Accrued interest receivable 2,239 Office properties and equipment, net 6,815 Bank-owned life insurance 22,096 Deferred tax assets, net 3,534 Core deposit and other intangibles 7,467 Other assets 767 Total assets acquired $ 961,646 Liabilities assumed: Deposits $ 782,698 Borrowings 82,761 Advance payments by borrowers for taxes and insurance 356 Accrued expenses and other liabilities 14,584 Total liabilities assumed $ 880,399 Net assets acquired $ 81,247 Cash paid for purchase 136,294 Goodwill recorded at merger $ 55,047 April 1, 2020 Assets acquired: Cash and cash equivalents $ 155,248 Debt securities available for sale 51,479 Debt securities held to maturity 13,418 Equity securities 1,796 Federal Home Loan Bank stock 2,010 Loans receivable 171,593 Accrued interest receivable 679 Office properties and equipment, net 5,774 Bank-owned life insurance 17,245 Deferred tax assets, net 1,334 Other assets 1,489 Total assets acquired $ 422,065 Liabilities assumed: Deposits $ 333,234 Borrowings 37,728 Advance payments by borrowers for taxes and insurance 982 Accrued expenses and other liabilities 5,400 Total liabilities assumed $ 377,344 Net assets acquired $ 44,721 Fair market value of stock issued to Columbia Bank MHC for purchase 68,530 Goodwill recorded at merger $ 23,809

Debt Securities Available for_2

Debt Securities Available for Sale (Tables)	12 Months Ended
	Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Debt securities, available-for-sale	Debt securities available for sale at December 31, 2020 and 2019 are summarized as follows: December 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (In thousands) U.S. government and agency obligations $ 24,425 $ 1,124 $ — $ 25,549 Mortgage-backed securities and collateralized mortgage obligations 1,163,613 37,343 (562) 1,200,394 Municipal obligations 16,845 17 — 16,862 Corporate debt securities 67,628 2,264 (415) 69,477 Trust preferred securities 5,000 — (330) 4,670 $ 1,277,511 $ 40,748 $ (1,307) $ 1,316,952 December 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (In thousands) U.S. government and agency obligations $ 42,081 $ 321 $ (16) $ 42,386 Mortgage-backed securities and collateralized mortgage obligations 968,165 12,981 (1,265) 979,881 Municipal obligations 2,284 1 (1) 2,284 Corporate debt securities 68,613 945 (378) 69,180 Trust preferred securities 5,000 — (395) 4,605 $ 1,086,143 $ 14,248 $ (2,055) $ 1,098,336
Investments classified by contractual maturity date	The amortized cost and fair value of debt securities available for sale at December 31, 2020, by contractual final maturity, is shown below. Expected maturities may differ from contractual maturities due to prepayment or early call options exercised by the issuer. (4) Debt Securities Available for Sale (continued) December 31, 2020 Amortized Cost Fair Value (In thousands) One year or less $ 21,378 $ 21,380 More than one year to five years 47,429 49,276 More than five years to ten years 45,091 45,902 $ 113,898 $ 116,558 Mortgage-backed securities and collateralized mortgage obligations 1,163,613 1,200,394 $ 1,277,511 $ 1,316,952 December 31, 2020 Amortized Cost Fair Value (In thousands) More than one year to five years $ 5,000 $ 5,001 Mortgage-backed securities and collateralized mortgage obligations 257,720 272,090 $ 262,720 $ 277,091
Debt securities, available-for-sale, unrealized loss position, fair value	The following tables summarize the fair value and gross unrealized losses of those securities that reported an unrealized loss at December 31, 2020 and 2019 and if the unrealized loss position was continuous for the twelve months prior to those respective dates: December 31, 2020 Less Than 12 Months 12 Months or Longer Total Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) (In thousands) Mortgage-backed securities and collateralized mortgage obligations $ 117,978 $ (481) $ 24,018 $ (81) $ 141,996 $ (562) Corporate debt securities 9,845 (155) 5,740 (260) 15,585 (415) Trust preferred securities — — 4,670 (330) 4,670 (330) $ 127,823 $ (636) $ 34,428 $ (671) $ 162,251 $ (1,307) (4) Debt Securities Available for Sale (continued) December 31, 2019 Less Than 12 Months 12 Months or Longer Total Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) (In thousands) U.S. government and agency obligations $ 5,106 $ (13) $ 4,988 $ (3) $ 10,094 $ (16) Mortgage-backed securities and collateralized mortgage obligations 178,665 (946) 58,208 (319) 236,873 (1,265) Municipal obligations 696 (1) — — 696 (1) Corporate debt securities 2,588 (5) 4,627 (373) 7,215 (378) Trust preferred securities — — 4,605 (395) 4,605 (395) $ 187,055 $ (965) $ 72,428 $ (1,090) $ 259,483 $ (2,055)

Debt Securities Held to Matur_2

Debt Securities Held to Maturity (Tables)	12 Months Ended
	Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Debt securities, held-to-maturity	Debt securities held to maturity at December 31, 2020 and 2019 are summarized as follows: December 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (In thousands) U.S. government and agency obligations $ 5,000 $ 1 $ — $ 5,001 Mortgage-backed securities and collateralized mortgage obligations 257,720 14,372 (2) 272,090 $ 262,720 $ 14,373 $ (2) $ 277,091 December 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Fair Value (In thousands) U.S. government and agency obligations $ 20,000 $ 26 $ (66) $ 19,960 Mortgage-backed securities and collateralized mortgage obligations 265,756 4,048 (259) 269,545 $ 285,756 $ 4,074 $ (325) $ 289,505
Investments classified by contractual maturity date	The amortized cost and fair value of debt securities available for sale at December 31, 2020, by contractual final maturity, is shown below. Expected maturities may differ from contractual maturities due to prepayment or early call options exercised by the issuer. (4) Debt Securities Available for Sale (continued) December 31, 2020 Amortized Cost Fair Value (In thousands) One year or less $ 21,378 $ 21,380 More than one year to five years 47,429 49,276 More than five years to ten years 45,091 45,902 $ 113,898 $ 116,558 Mortgage-backed securities and collateralized mortgage obligations 1,163,613 1,200,394 $ 1,277,511 $ 1,316,952 December 31, 2020 Amortized Cost Fair Value (In thousands) More than one year to five years $ 5,000 $ 5,001 Mortgage-backed securities and collateralized mortgage obligations 257,720 272,090 $ 262,720 $ 277,091
Schedule of unrealized loss on investments	The following tables summarize the fair value and gross unrealized losses of those securities that reported an unrealized loss at December 31, 2020 and 2019 and if the unrealized loss position was continuous for the twelve months prior to those respective dates: December 31, 2020 Less Than 12 Months 12 Months or Longer Total Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) (In thousands) Mortgage-backed securities and collateralized mortgage obligations $ 2,176 $ (2) $ — $ — $ 2,176 $ (2) (5) Debt Securities Held to Maturity (continued) December 31, 2019 Less than 12 months 12 months or longer Total Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) Fair Value Gross Unrealized (Losses) (In thousands) U.S. government and agency obligations $ 9,934 $ (66) $ — $ — $ 9,934 $ (66) Mortgage-backed securities and collateralized mortgage obligations 27,911 (251) 772 (8) 28,683 (259) $ 37,845 $ (317) $ 772 $ (8) $ 38,617 $ (325)

Loans Receivable and Allowanc_2

Loans Receivable and Allowance for Loan Losses (Tables)	12 Months Ended
	Dec. 31, 2020
Receivables [Abstract]
Schedule of loans receivable	Loans receivable at December 31, 2020 and 2019 are summarized as follows: December 31, 2020 2019 (In thousands) Real estate loans: One-to-four family $ 1,940,327 $ 2,077,079 Multifamily and commercial 2,817,965 2,919,985 Construction 328,711 298,942 Commercial business loans 752,870 483,215 Consumer loans: Home equity loans and advances 321,177 388,127 Other consumer loans 1,497 1,960 Total gross loans 6,162,547 6,169,308 Purchased credit-impaired loans 6,345 7,021 Net deferred loan costs, fees and purchased premiums and discounts 12,878 21,237 Loans receivable $ 6,181,770 $ 6,197,566
Schedule of aging of loans receivable by portfolio segment	The following tables summarize the aging of loans receivable by portfolio segment, including non-accrual loans and excluding PCI loans at December 31, 2020 and 2019: December 31, 2020 30-59 Days 60-89 Days 90 Days or More Total Past Due Non-accrual Current Total (In thousands) Real estate loans: One-to-four family $ 3,068 $ 912 $ 1,901 $ 5,881 $ 2,637 $ 1,931,809 $ 1,940,327 Multifamily and commercial 15,645 — 1,238 16,883 1,873 2,799,209 2,817,965 Construction 550 — — 550 — 328,161 328,711 Commercial business loans 2,343 1,056 2,453 5,852 2,968 744,050 752,870 Consumer loans: Home equity loans and advances 1,156 696 394 2,246 678 318,253 321,177 Other consumer loans 4 — — 4 — 1,493 1,497 Total loans $ 22,766 $ 2,664 $ 5,986 31,416 $ 8,156 $ 6,122,975 $ 6,162,547 December 31, 2019 30-59 Days 60-89 Days 90 Days or More Total Past Due Non-accrual Current Total (In thousands) Real estate loans: One-to-four family $ 6,249 $ 2,132 $ 1,638 $ 10,019 $ 1,732 $ 2,065,328 $ 2,077,079 Multifamily and commercial 626 1,210 716 2,552 716 2,916,717 2,919,985 Construction — — — — — 298,942 298,942 Commercial business loans 1,056 — 2,489 3,545 3,686 475,984 483,215 Consumer loans: Home equity loans and advances 1,708 246 405 2,359 553 385,215 388,127 Other consumer loans 3 — — 3 — 1,957 1,960 Total loans $ 9,642 $ 3,588 $ 5,248 18,478 $ 6,687 $ 6,144,143 $ 6,169,308
Schedule of PCI loans acquired	The following table presents information regarding the estimates of the contractually required payments, the cash flows expected to be collected, and the estimated fair value of the PCI loans acquired in the Stewardship acquisition as of November 1, 2019 (See note 3 for more details): November 1, 2019 (In thousands) Contractually required principal and interest $ 9,286 Contractual cash flows not expected to be collected (non-accretable difference) (1,823) Expected cash flows to be collected 7,463 Interest component of expected cash flows (accretable yield) (556) Fair value of acquired loans $ 6,907 The following table presents information regarding the estimates of the contractually required payments, the cash flows expected to be collected, and the estimated fair value of the PCI loans acquired in the Roselle acquisition as of April 1, 2020 (See note 3 for more details): April 1, 2020 (In thousands) Contractually required principal and interest $ 461 Contractual cash flows not expected to be collected (non-accretable difference) (237) Expected cash flows to be collected 224 Interest component of expected cash flows (accretable yield) (51) Fair value of acquired loans $ 173 (7) Loans Receivable and Allowance for Loan Losses (continued) The following table presents changes in accretable yield for PCI loans for the years ended December 31, 2020 and 2019: December 31, 2020 2019 (In thousands) Balance at beginning of period $ 511 $ — Acquisition 58 556 Accretion (34) (30) Net change in expected cash flows (117) (15) Balance at end of period $ 418 $ 511
Schedule of loans receivable by portfolio segment and impairment method	The following tables summarize loans receivable (including PCI loans) and allowance for loan losses by portfolio segment and impairment method at December 31, 2020 and 2019: December 31, 2020 One-to-Four Family Multifamily and Commercial Construction Commercial Business Home Equity Loans and Advances Other Consumer Loans Total (In thousands) Allowance for loan losses: Individually evaluated for impairment $ 391 $ 601 $ — $ 84 $ 12 $ — $ 1,088 Collectively evaluated for impairment 13,195 30,080 11,271 17,300 1,736 6 73,588 Loans acquired with deteriorated credit quality — — — — — — — Total $ 13,586 $ 30,681 $ 11,271 $ 17,384 $ 1,748 $ 6 $ 74,676 Total loans: Individually evaluated for impairment $ 7,257 $ 32,792 $ — $ 3,447 $ 1,651 $ — $ 45,147 Collectively evaluated for impairment 1,933,070 2,785,173 328,711 749,423 319,526 1,497 6,117,400 Loans acquired with deteriorated credit quality 309 4,893 — 1,143 — — 6,345 Total loans $ 1,940,636 $ 2,822,858 $ 328,711 $ 754,013 $ 321,177 $ 1,497 $ 6,168,892 (7) Loans Receivable and Allowance for Loan Losses (continued) December 31, 2019 One-to-Four Family Multifamily and Commercial Construction Commercial Business Home Equity Loans and Advances Other Consumer Loans Total (In thousands) Allowance for loan losses: Individually evaluated for impairment $ 484 $ 2 $ — $ 1,121 $ 14 $ — $ 1,621 Collectively evaluated for impairment 13,296 22,978 7,435 14,715 1,655 9 60,088 Loans acquired with deteriorated credit quality — — — — — — — Total $ 13,780 $ 22,980 $ 7,435 $ 15,836 $ 1,669 $ 9 $ 61,709 Total loans: Individually evaluated for impairment $ 8,891 $ 2,599 $ — $ 5,178 $ 2,143 $ — $ 18,811 Collectively evaluated for impairment 2,068,188 2,917,386 298,942 478,037 385,984 1,960 6,150,497 Loans acquired with deteriorated credit quality 429 4,866 — 1,726 — — 7,021 Total loans $ 2,077,508 $ 2,924,851 $ 298,942 $ 484,941 $ 388,127 $ 1,960 $ 6,176,329 Years Ended December 31, 2020 2019 2018 (In thousands) Balance at beginning of period $ 61,709 $ 62,342 $ 58,178 Provision charged 18,447 4,224 6,677 Recoveries 823 496 707 Charge-offs (6,303) (5,353) (3,220) Balance at end of period $ 74,676 $ 61,709 $ 62,342 For the Year Ended December 31, 2020 One-to-Four Family Multifamily and Commercial Construction Commercial Business Home Equity Loans and Advances Other Consumer Loans Total (In thousands) Balance at beginning of period $ 13,780 $ 22,980 $ 7,435 $ 15,836 $ 1,669 $ 9 $ 61,709 Provision charged (credited) 1,299 7,713 3,835 5,360 239 1 18,447 Recoveries 438 16 1 308 60 — 823 Charge-offs (1,931) (28) — (4,120) (220) (4) (6,303) Balance at end of period $ 13,586 $ 30,681 $ 11,271 $ 17,384 $ 1,748 $ 6 $ 74,676 For the Year Ended December 31, 2019 One-to-Four Family Multifamily and Commercial Construction Commercial Business Home Equity Loans and Advances Other Consumer Loans Total (In thousands) Balance at beginning of period $ 15,232 $ 23,251 $ 7,217 $ 14,176 $ 2,458 $ 8 $ 62,342 Provision charged (credited) (429) (178) 216 5,250 (638) 3 4,224 Recoveries 30 10 2 404 50 — 496 Charge-offs (1,053) (103) — (3,994) (201) (2) (5,353) Balance at end of period $ 13,780 $ 22,980 $ 7,435 $ 15,836 $ 1,669 $ 9 $ 61,709 For the Year Ended December 31, 2018 One-to-Four Family Multifamily and Commercial Construction Commercial Business Home Equity Loans and Advances Other Consumer Loans Unallocated Total (In thousands) Balance at beginning of period $ 19,991 $ 19,933 $ 5,217 $ 8,275 $ 4,576 $ 8 $ 178 $ 58,178 Provision charged (credited) (4,503) 3,445 1,997 7,860 (1,949) 5 (178) 6,677 Recoveries 334 2 3 240 122 6 — 707 Charge-offs (590) (129) — (2,199) (291) (11) — (3,220) Balance at end of period $ 15,232 $ 23,251 $ 7,217 $ 14,176 $ 2,458 $ 8 $ — $ 62,342
Schedule of troubled debt restructuring	The following tables present the number of loans modified as TDRs during the years ended December 31, 2020, 2019 and 2018, along with their balances immediately prior to the modification date and post-modification. Post-modification recorded investment represents the net book balance immediately following modification. (7) Loans Receivable and Allowance for Loan Losses (continued) For the Years Ended December 31, 2020 2019 No. of Loans Pre-modification Recorded Investment Post-modification Recorded Investment No. of Loans Pre-modification Recorded Investment Post-modification Recorded Investment (Dollars in thousands) Troubled Debt Restructurings Real estate loans: Multifamily and commercial 5 $ 17,022 $ 17,022 — $ — $ — Commercial business loans 2 11,507 12,802 1 4,095 4,095 Total restructured loans 7 $ 28,529 $ 29,824 1 $ 4,095 $ 4,095 For the Year Ended December 31, 2018 No. of Loans Pre-modification Recorded Investment Post-modification Recorded Investment (Dollars in thousands) Troubled Debt Restructurings Real estate loans: One-to-four family 5 $ 801 $ 801 Multifamily and commercial 1 65 65 Consumer loans: Home equity loans and advances 1 588 588 Total restructured loans 7 $ 1,454 $ 1,454
Schedule of loans individually evaluated for impairment	The following tables present loans individually evaluated for impairment by loan segment, excluding PCI loans, at December 31, 2020 and 2019: At December 31, 2020 Recorded Investment Unpaid Principal Balance Specific Allowance (In thousands) With no allowance recorded: Real estate loans: One-to-four family $ 3,344 $ 3,898 $ — Multifamily and commercial 13,058 13,094 — Commercial business loans 1,945 1,945 — Consumer loans: Home equity loans and advances 714 851 — 19,061 19,788 — With a specific allowance recorded: Real estate loans: One-to-four family 3,913 3,919 391 Multifamily and commercial 19,734 20,350 601 Commercial business loans 1,502 1,502 84 Consumer loans: Home equity loans and advances 937 937 12 26,086 26,708 1,088 Total: Real estate loans: One-to-four family 7,257 7,817 391 Multifamily and commercial 32,792 33,444 601 Commercial business loans 3,447 3,447 84 Consumer loans: Home equity loans and advances 1,651 1,788 12 Total loans $ 45,147 $ 46,496 $ 1,088 At December 31, 2019 Recorded Investment Unpaid Principal Balance Specific Allowance (In thousands) With no allowance recorded: Real estate loans: One-to-four family $ 4,314 $ 5,473 $ — Multifamily and commercial 1,494 2,191 — Commercial business loans 3,859 4,048 — Consumer loans: Home equity loans and advances 1,080 1,217 — 10,747 12,929 — With a specific allowance recorded: Real estate loans: One-to-four family 4,577 4,613 484 Multifamily and commercial 1,105 1,105 2 Commercial business loans 1,319 4,307 1,121 Consumer loans: Home equity loans and advances 1,063 1,063 14 8,064 11,088 1,621 Total: Real estate loans: One-to-four family 8,891 10,086 484 Multifamily and commercial 2,599 3,296 2 Commercial business loans 5,178 8,355 1,121 Consumer loans: Home equity loans and advances 2,143 2,280 14 Total loans $ 18,811 $ 24,017 $ 1,621 For the Years Ended December 31, 2020 2019 2018 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized (In thousands) Real estate loans: One-to-four family $ 7,946 $ 305 $ 8,811 $ 434 $ 10,224 $ 445 Multifamily and commercial 23,701 1,091 2,639 147 2,712 155 Construction — — 850 — — — Commercial business loans 4,963 216 6,378 479 3,060 118 Consumer loans: Home equity loans and advances 1,909 100 2,562 143 3,361 173 Totals $ 38,519 $ 1,712 $ 21,240 $ 1,203 $ 19,357 $ 891
Schedule of loans receivable by credit quality risk	The following tables present loans receivable by credit quality risk indicator and by loan segment, excluding PCI loans at December 31, 2020 and 2019: December 31, 2020 One-to-Four Family Multifamily and Commercial Construction Commercial Business Home Equity Loans and Advances Other Consumer Loans Total (In thousands) Pass $ 1,935,032 $ 2,758,905 $ 328,711 $ 740,010 $ 320,092 $ 1,497 $ 6,084,247 Special mention 404 40,392 — 6,718 — — 47,514 Substandard 4,891 18,668 — 6,142 1,085 — 30,786 Doubtful — — — — — — — Total $ 1,940,327 $ 2,817,965 $ 328,711 $ 752,870 $ 321,177 $ 1,497 $ 6,162,547 (7) Loans Receivable and Allowance for Loan Losses (continued) December 31, 2019 One-to-Four Family Multifamily and Commercial Construction Commercial Business Home Equity Loans and Advances Other Consumer Loans Total (In thousands) Pass $ 2,072,878 $ 2,900,286 $ 298,942 $ 454,183 $ 387,251 $ 1,960 $ 6,115,500 Special mention 419 4,724 — 20,170 — — 25,313 Substandard 3,782 14,975 — 8,862 876 — 28,495 Doubtful — — — — — — — Total $ 2,077,079 $ 2,919,985 $ 298,942 $ 483,215 $ 388,127 $ 1,960 $ 6,169,308

Office Properties and Equipme_2

Office Properties and Equipment, net (Tables)	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Schedule of Office Properties and Equipment	Office properties and equipment less accumulated depreciation at December 31, 2020 and 2019 are summarized as follows: December 31, 2020 2019 (In thousands) Land $ 10,174 $ 11,069 Buildings 31,523 27,340 Land and building improvements 35,307 31,520 Leasehold improvements 22,166 24,038 Furniture and equipment 33,971 36,828 133,141 130,795 Less accumulated depreciation and amortization 57,167 57,828 Total office properties and equipment, net $ 75,974 $ 72,967

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Lessee, Operating Lease, Liability, Maturity	The following table summarizes lease payment obligations for each of the next five years and thereafter as follows: At December 31, 2020 Lease Payment Obligations (In thousands) 2021 $ 4,010 2022 3,624 2023 3,310 2024 2,586 2025 1,914 Thereafter 6,620 Total undiscounted cash flows 22,064 Discount on cash flows (1,992) Total lease liability $ 20,072

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill and Intangible Assets	Intangible assets at December 31, 2020 and 2019 are summarized as follows: December 31, 2020 2019 (In thousands) Goodwill $ 80,285 $ 60,763 Core deposit intangibles 6,197 7,245 Mortgage servicing rights 902 574 $ 87,384 $ 68,582
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	Scheduled amortization of core deposit intangibles for each of the next five years and thereafter is as follows: Year Ending December 31, Core Deposit Intangible Amortization (In thousands) 2021 $ 1,024 2022 961 2023 892 2024 819 2025 737 Thereafter 1,764 Total $ 6,197

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2020
Deposits [Abstract]
Schedule of Deposits	Deposits at December 31, 2020 and 2019 are summarized as follows: December 31, 2020 2019 Balance Weighted Average Rate Balance Weighted Average Rate (Dollars in thousands) Non-interest-bearing demand $ 1,354,605 — % $ 958,442 — % Interest-bearing demand 2,189,164 0.40 1,720,383 1.03 Money market accounts 588,180 0.36 410,392 0.91 Savings and club deposits 688,309 0.16 543,480 0.15 Certificates of deposit 1,958,366 1.44 2,013,145 2.25 Total deposits $ 6,778,624 0.59 % $ 5,645,842 1.20 %
Schedule of Certificate Accounts by Maturity	Scheduled maturities of certificates of deposit accounts at December 31, 2020 and 2019 are summarized as follows: December 31, 2020 2019 (In thousands) One year or less $ 1,494,129 $ 1,293,613 After one year to two years 337,579 548,995 After two years to three years 52,809 142,458 After three years to four years 23,018 11,362 After four years 50,831 16,717 $ 1,958,366 $ 2,013,145 Interest expense on deposits for the years ended December 31, 2020, 2019, and 2018 are summarized as follows: Years Ended December 31, 2020 2019 2018 (In thousands) Demand (including money market accounts) $ 15,556 $ 19,922 $ 12,933 Savings and club deposits 1,023 770 993 Certificates of deposit 38,667 40,859 25,597 $ 55,246 $ 61,551 $ 39,523

Borrowings (Tables)

Borrowings (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Schedule of borrowed funds	Borrowings at December 31, 2020 and 2019 are summarized as follows: December 31, 2020 2019 2020 2019 Balance Weighted Average Interest Rate (In thousands) Overnight lines of credit $ — $ 107,800 — % 1.81 % FHLB advances 792,412 1,275,391 1.18 2.09 Subordinated notes — 16,899 — 6.75 Junior subordinated debentures 6,952 6,932 3.20 5.09 $ 799,364 $ 1,407,022 1.20 % 2.14 %
Schedule of borrowed funds contractual maturity	Scheduled maturities of FHLB advances at December 31, 2020 are summarized as follows: Year Ended December 31, 2020 (In thousands) One year or less $ 496,042 After one year to two years 179,706 After two years to three years 40,391 After three years to four years 51,273 After four years 25,000 Total FHLB advances $ 792,412

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Public Utilities General Disclosures	The following table presents the Company's and the Bank's actual capital amounts and ratios at December 31, 2020 and 2019 compared to the Federal Reserve Bank minimum capital adequacy requirements and the Federal Reserve Bank requirements for classification as a well-capitalized institution: (13) Stockholders' Equity (continued) Regulatory Capital (continued) Actual Minimum Capital Adequacy Requirements Minimum Capital Adequacy Requirements With Capital Conservation Buffer To Be Well Capitalized Under Prompt Corrective Action Provisions Amount Ratio Amount Ratio Amount Ratio Amount Ratio Company (In thousands, except ratio data) At December 31, 2020: Total capital (to risk-weighted assets) $ 1,070,361 18.54 % $ 461,766 8.00 % $ 606,068 10.50 % N/A N/A Tier 1 capital (to risk-weighted assets) 998,172 17.29 346,325 6.00 490,627 8.50 N/A N/A Common equity tier 1 capital (to risk-weighted assets) 990,955 17.17 259,744 4.50 404,046 7.00 N/A N/A Tier 1 capital (to adjusted total assets) 998,172 11.38 350,923 4.00 350,923 4.00 N/A N/A At December 31, 2019: Total capital (to risk-weighted assets) $ 1,061,555 17.25 % $ 492,438 8.00 % $ 646,324 10.50 % N/A N/A Tier 1 capital (to risk-weighted assets) 988,172 16.05 369,328 6.00 523,215 8.50 N/A N/A Common equity tier 1 capital (to risk-weighted assets) 980,995 15.94 276,996 4.50 430,883 7.00 N/A N/A Tier 1 capital (to adjusted total assets) 988,172 12.92 305,824 4.00 305,824 4.00 N/A N/A Bank At December 31, 2020: Total capital (to risk-weighted assets) $ 924,959 16.05 % $ 460,944 8.00 % $ 604,989 10.50 % $ 576,180 10.00 % Tier 1 capital (to risk-weighted assets) 852,897 14.80 345,708 6.00 489,753 8.50 460,944 8.00 Common equity tier 1 capital (to risk-weighted assets) 852,897 14.80 259,281 4.50 403,326 7.00 374,517 6.50 Tier 1 capital (to adjusted total assets) 852,897 9.72 350,815 4.00 350,815 4.00 438,519 5.00 At December 31, 2019: Total capital (to risk-weighted assets) $ 844,664 14.25 % $ 474,125 8.00 % $ 622,290 10.50 % $ 592,657 10.00 % Tier 1 capital (to risk-weighted assets) 782,881 13.21 355,594 6.00 503,758 8.50 474,125 8.00 Common equity tier 1 capital (to risk-weighted assets) 782,881 13.21 266,696 4.50 414,860 7.00 385,227 6.50 Tier 1 capital (to adjusted total assets) 782,881 10.25 305,423 4.00 305,423 4.00 381,779 5.00

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
Changes in Projected Benefit Obligations, Fair Value of Plan Assets, and Funded Status of Plan	The following table sets forth information regarding the Pension, RIM, Post-retirement and Split-Dollar Life Insurance Plans at December 31, 2020 and 2019: (14) Employee Benefit Plans (continued) Pension Plan, Retirement Income Maintenance Plan (the "RIM Plan") Post-retirement Plan, Split-Dollar Life Insurance Plans (cont'd) December 31, 2020 2019 2020 2019 2020 2019 2020 2019 Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance (In thousands) Change in benefit obligation: Benefit obligation at beginning of year $ 263,826 $ 209,205 $ 13,696 $ 11,285 $ 24,603 $ 20,964 $ 14,100 $ 10,462 Acquired — — — — — — 1,981 310 Service cost 7,985 6,494 267 210 394 339 467 354 Interest cost 7,608 8,569 405 466 683 826 507 457 Actuarial (gain) loss 40,281 46,001 2,506 2,074 5,506 3,141 3,137 2,649 Benefits paid (7,260) (6,443) (344) (339) (565) (667) (211) (132) Benefit obligation at end of year 312,440 263,826 16,530 13,696 30,621 24,603 19,981 14,100 Change in plan assets: Fair value of plan assets at beginning of year 356,347 272,974 — — — — — — Actuarial return on plan assets 50,820 54,816 — — — — — — Employer contributions 12,000 35,000 344 339 565 667 211 132 Benefits paid (7,260) (6,443) (344) (339) (565) (667) (211) (132) Fair value of plan assets at end of year 411,907 356,347 — — — — — — Funded status at end of year $ 99,467 $ 92,521 $ (16,530) $ (13,696) $ (30,621) $ (24,603) $ (19,981) $ (14,100)
Schedule of Net Benefit Costs	Net periodic benefit (income) cost for the Pension Plan, RIM Plan, Post-retirement Plan and Split-dollar Life Insurance plan benefits for the years ended December 31, 2020 and 2019, and 2018, includes the following components: For the Year Ended December 31, 2020 Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance Affected Line Item in the Consolidated Statements of Income (In thousands) Service cost $ 7,985 $ 267 $ 394 $ 467 Compensation and employee benefits Interest cost 7,608 405 683 507 Other non-interest expense Expected return on plan assets (23,375) — — — Other non-interest expense Amortization: Prior service cost — — — 56 Other non-interest expense Net loss 4,902 397 309 454 Other non-interest expense Net periodic (income) benefit cost $ (2,880) $ 1,069 $ 1,386 $ 1,484 (14) Employee Benefit Plans (continued) Pension Plan, Retirement Income Maintenance Plan (the "RIM Plan") Post-retirement Plan, Split-Dollar Life Insurance Plans (cont'd) For the Year Ended December 31, 2019 Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance Affected Line Item in the Consolidated Statements of Income (In thousands) Service cost $ 6,494 $ 210 $ 339 $ 354 Compensation and employee benefits Interest cost 8,569 466 826 457 Other non-interest expense Expected return on plan assets (21,058) — — — Other non-interest expense Amortization: Prior service cost — — — 56 Other non-interest expense Net loss 3,070 244 147 247 Other non-interest expense Net periodic (income) benefit cost $ (2,925) $ 920 $ 1,312 $ 1,114 For the Year Ended December 31, 2018 Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance Affected Line Item in the Consolidated Statements of Income (In thousands) Service cost $ 7,805 $ 282 $ 417 $ 374 Compensation and employee benefits Interest cost 8,489 443 796 428 Other non-interest expense Expected return on plan assets (20,794) — — — Other non-interest expense Amortization: Prior service cost — — (106) 32 Other non-interest expense Net loss 3,117 413 323 506 Other non-interest expense Net periodic (income) benefit cost $ (1,383) $ 1,138 $ 1,430 $ 1,340
Condensed Income Statement	The following table summarizes the impact of retrospective application of ASU 2017-07 to the Consolidated Statements of Income for the year ended December 31, 2018: Year Ended December 31, 2018 (In thousands) Compensation and employee benefits: As previously reported $ 69,907 As reported under ASU 2017-07 77,226 Other non-interest expense: As previously reported $ 12,916 As reported under ASU 2017-07 5,597
Schedule of Amounts Recognized in Other Comprehensive Income (Loss)	The components of accumulated other comprehensive income related to the Pension Plan, RIM Plan, and Post-retirement Plan on a pre-tax basis, at December 31, 2020, 2019, and $2018, are summarized in the following table: At December 31, 2020 2019 Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance (In thousands) Unrecognized prior service costs $ — $ — $ — $ 405 $ — $ — $ — $ 461 Unrecognized net actuarial income 76,686 7,686 12,417 8,741 68,752 5,777 7,221 6,058 Total accumulated other comprehensive income $ 76,686 $ 7,686 $ 12,417 $ 9,146 $ 68,752 $ 5,777 $ 7,221 $ 6,519 (14) Employee Benefit Plans (continued) Pension Plan, Retirement Income Maintenance Plan (the "RIM Plan") Post-retirement Plan, Split-Dollar Life Insurance Plans (cont'd) At December 31 2018 Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance (In thousands) Unrecognized prior service costs $ — $ — $ — $ 517 Unrecognized net actuarial income 59,579 3,748 4,226 3,658 Total accumulated other comprehensive income $ 59,579 $ 3,748 $ 4,226 $ 4,175 At and For the Years Ended December 31, 2020 Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance Weighted average assumptions used to determine benefit obligation: Discount rate 2.920 % 2.670 % 2.590 % 3.010 % Rate of compensation increase 3.750 3.750 N/A 3.750 Weighted average assumptions used to determine net periodic benefit cost: Discount Rates: Benefit obligation 3.490 % 3.330 % 3.270 % 3.540 % Remeasurement rate 2.740 N/A N/A N/A Service cost 3.660 3.460 3.520 3.710 Remeasurement rate 2.970 N/A N/A N/A Interest cost 3.120 3.000 2.850 3.280 Remeasurement rate 2.220 N/A N/A N/A Expected rate of return on plan assets 6.500 N/A N/A N/A Rate of compensation increase 3.500 3.500 N/A 3.500 At and For the Years Ended December 31, 2019 Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance Weighted average assumptions used to determine benefit obligation: Discount rate 3.490 % 3.330 % 3.270 % 3.540 % Rate of compensation increase 3.500 3.500 N/A 3.500 Weighted average assumptions used to determine net periodic benefit cost: Discount Rates: Benefit obligation 4.570 % 4.470 % 4.410 % 4.630 % Remeasurement rate 3.850 N/A N/A N/A Service cost 4.700 4.570 4.600 4.740 Remeasurement rate 4.040 N/A N/A N/A Interest cost 4.250 4.180 4.050 4.390 Remeasurement rate 3.440 N/A N/A N/A Expected rate of return on plan assets 7.000 N/A N/A N/A Rate of compensation increase 3.500 3.500 N/A 3.500 (14) Employee Benefit Plans (continued) Pension Plan, Retirement Income Maintenance Plan (the "RIM Plan") Post-retirement Plan, Split-Dollar Life Insurance Plans (cont'd) At and For the Years Ended December 31, 2018 Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance Weighted average assumptions used to determine benefit obligation: Discount rate 4.570 % 4.470 % 4.410 % 4.630 % Rate of compensation increase 3.500 3.500 N/A 3.500 Weighted average assumptions used to determine net periodic benefit cost: Discount Rates: Benefit obligation 3.750 % 4.470 % 3.625 % 3.750 % Service cost N/A 4.570 N/A N/A Interest cost N/A 4.180 N/A N/A Expected rate of return on plan assets 7.250 N/A N/A N/A Rate of compensation increase 3.500 3.500 N/A 3.500
Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates	A 1% change in the assumed health care cost trend rate would have the following effects on post-retirement benefits at December 31, 2020: 1% increase 1% decrease (In thousands) Effect on total service cost and interest cost $ 19 $ (16) Effect on post-retirement benefit obligations 175 (154)
Schedule of Expected Benefit Payments	Estimated future benefit payments, which reflect expected future service, as appropriate for the next five years and thereafter are as follows: Pension Plan RIM Plan Post-retirement Plan Split-Dollar Life Insurance (In thousands) 2021 $ 8,568 $ 384 $ 1,490 $ 270 2022 9,141 436 1,525 312 2023 9,847 534 1,559 363 2024 10,592 673 1,622 412 2025 11,388 778 1,675 461 2026 - 2030 68,978 4,415 8,820 3,179
Schedule of Allocation of Plan Assets	The weighted average asset allocation of pension assets at December 31, 2020 and 2019 were as follows: December 31, 2020 2019 Domestic equities 44.1 % 39.6 % Foreign equities 13.4 % 9.6 % Fixed income 37.8 % 44.3 % Real estate 4.4 % 6.1 % Cash 0.3 % 0.4 % Total 100.0 % 100.0 % Allowable Range Equities 40-60% Fixed income 40-60% Real estate 0-10% Cash 0-15% (14) Employee Benefit Plans (continued) Pension Plan, Retirement Income Maintenance Plan (the "RIM Plan") Post-retirement Plan, Split-Dollar Life Insurance Plans (cont'd) December 31, 2020 Fair Value Measurements Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In thousands) Money market mutual funds $ 1,434 $ 1,434 $ — $ — Mutual funds - value stock fund 29,914 29,914 — — Mutual funds - fixed income 155,864 155,864 — — Mutual funds - international stock 55,300 55,300 — — Mutual funds - institutional stock index 151,436 151,436 — — Commingled real estate funds 17,959 — 17,959 — $ 411,907 $ 393,948 $ 17,959 $ — December 31, 2019 Fair Value Measurements Fair value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In thousands) Money market mutual funds $ 1,462 $ 1,462 $ — $ — Mutual funds - value stock fund 27,827 27,827 — — Mutual funds - fixed income 158,030 158,030 — — Mutual funds - international stock 34,332 34,332 — — Mutual funds - institutional stock index 113,100 113,100 — — Commingled real estate funds 21,596 — 21,596 — $ 356,347 $ 334,751 $ 21,596 $ —
Employee Stock Ownership Plan (ESOP) Disclosures	The ESOP shares were as follows: December 31, 2020 2019 (In thousands) Allocated shares 606 385 Unearned shares 3,929 4,156 Total ESOP shares 4,535 4,541 Fair value of unearned ESOP shares $ 61,139 $ 70,409
Nonvested Restricted Stock Shares Activity	The following is a summary of the Company's restricted stock activity during the years ended December 31, 2020 and 2019: Number of Restricted Shares Weighted Average Grant Date Fair Value Non-vested at January 1, 2019 — $ — Grants 1,464,243 15.67 Forfeited (44,231) 15.60 Non-vested at December 31, 2019 1,420,012 $ 15.67 Grants 33,160 15.08 Vested (172,756) 15.66 Forfeited (17,247) 16.02 Non-vested at December 31, 2020 1,263,169 $ 15.66
Share-based Payment Arrangement, Option, Activity	The following is a summary of the Company's option activity during the years ended December 31, 2020 and 2019: Number of Stock Options Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Outstanding January 1, 2019 — $ — — $ — Granted 3,892,279 15.60 9.6 — Forfeited (108,235) 15.60 — — Outstanding, December 31, 2019 3,784,044 $ 15.67 9.6 $ 4,812,490 Expired (10,457) 15.98 — — Forfeited (64,959) 15.84 — — Outstanding, December 31, 2020 3,708,628 $ 15.66 8.6 $ — Options exercisable at December 31, 2020 743,298 $ 15.66 8.5 $ —

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	The current and deferred amounts of income tax expense (benefit) for the years ended December 31, 2020, 2019, and 2018 are as follows: Years Ended December 31, 2020 2019 2018 (In thousands) Current: Federal $ 5,072 $ 5,933 $ 11,284 State 3,844 2,905 5,129 Total current 8,916 8,838 16,413 Deferred: Federal 9,847 8,275 (4,901) State (109) (748) (589) Total deferred 9,738 7,527 (5,490) Total income tax expense $ 18,654 $ 16,365 $ 10,923
Schedule of Effective Income Tax Rate Reconciliation	A reconciliation between the amount of reported total income tax expense and the amount computed by multiplying the applicable statutory federal income tax rate of 21% is as follows: Years Ended December 31, 2020 2019 2018 (In thousands) Tax expense at applicable statutory rate $ 16,013 $ 14,927 $ 7,067 Increase (decrease) in taxes resulting from: State tax, net of federal income tax benefit 2,951 1,704 3,587 ESOP fair market value adjustment 187 272 202 Tax exempt interest income (11) (6) (4) Income from Bank-owned life insurance (1,075) (1,246) (812) Dividend received deduction (9) (8) (16) Non-deductible merger-related expenses 42 222 — Non-deductible compensation expense — 398 — Other, net 556 102 899 Total income tax expense $ 18,654 $ 16,365 $ 10,923
Schedule of Deferred Tax Assets and Liabilities	The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at December 31, 2020 and 2019 are as follows: At December 31, 2020 2019 (In thousands) Deferred tax assets: Allowance for loan losses $ 20,878 $ 13,114 Post-retirement benefits 5,928 4,089 Deferred compensation 2,779 2,085 Depreciation — 1,002 Retirement Income Maintenance plan 2,471 1,725 ESOP 624 301 Stock-based compensation 2,724 788 Reserve for uncollected interest 126 54 Net unrealized losses on debt securities and defined benefit plans 18,511 18,374 Federal and State NOLs 9,719 2,063 Alternative minimum assessment carryforwards 2,156 2,156 Charitable contribution carryforward 6,359 5,981 Purchase accounting 1,024 — Lease liability 5,609 — Other items 3,215 332 Gross deferred tax assets 82,123 58,999 Valuation allowance (3,411) (7,442) 78,712 51,557 Deferred tax liabilities: Pension expense 49,225 33,856 Depreciation 6,118 — Deferred loan costs 8,555 5,911 Intangible assets 1,597 1,215 Lease right-of-use asset 5,317 — Other items 716 266 Total gross deferred tax liabilities 71,528 41,248 Net deferred tax asset $ 7,184 $ 10,309

Financial Transactions with O_2

Financial Transactions with Off-Balance-Sheet risk and Concentrations of Credit risk (Tables)	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Schedules of Concentration of Risk, by Risk Factor	At December 31, 2020 and 2019, the following commitments existed which are not reflected in the Consolidated Statements of Financial Condition: December 31, 2020 2019 (In thousands) Loan commitments: Residential real estate $ 149,847 $ 91,141 Multifamily and commercial real estate 98,910 95,025 Commercial business 16,842 18,737 Construction 13,335 59,990 Consumer including home equity loans and advances 3,264 5,988 Total loan commitments $ 282,198 $ 270,881

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of fair value assets and liabilities measured on recurring basis	The following tables present the assets and liabilities reported on the Consolidated Statements of Financial Condition at their fair values as of December 31, 2020 and 2019, by level within the fair value hierarchy: December 31, 2020 Fair Value Measurements Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In thousands) Debt securities available for sale: U.S. government and agency obligations $ 25,549 $ 25,549 $ — $ — Mortgage-backed securities and collateralized mortgage obligations 1,200,394 — 1,200,394 — Municipal obligations 16,862 — 16,862 — Corporate debt securities 69,477 — 69,477 — Trust preferred securities 4,670 — 4,670 — Total debt securities available for sale 1,316,952 25,549 1,291,403 — Equity securities 5,418 5,072 346 — Derivative assets 19,425 — 19,425 — $ 1,341,795 $ 30,621 1,311,174 $ — Derivative liabilities $ 42,384 $ — $ 42,384 $ — (17) Fair Value Measurements (continued) December 31, 2019 Fair Value Measurements Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In thousands) Debt securities available for sale: U.S. government and agency obligations $ 42,386 $ 42,386 $ — $ — Mortgage-backed securities and collateralized mortgage obligations 979,881 — 979,881 — Municipal obligations 2,284 — 2,284 — Corporate debt securities 69,180 — 69,180 — Trust preferred securities 4,605 — 4,605 — Total debt securities available for sale 1,098,336 42,386 1,055,950 — Equity securities 2,855 2,587 268 — Derivative assets 185 — 185 — $ 1,101,376 $ 44,973 $ 1,056,403 $ — Derivative liabilities $ 11,546 $ — $ 11,546 $ —
Schedule of fair value assets and liabilities measured on non-recurring basis	The following tables present the assets and liabilities reported on the Consolidated Statements of Financial Condition at their fair values on a non-recurring basis at December 31, 2020 and 2019, by level within the fair value hierarchy: December 31, 2020 Fair Value Measurements Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In thousands) Mortgage servicing rights $ 1,338 $ — $ — $ 1,338 $ 1,338 $ — $ — $ 1,338 December 31, 2019 Fair Value Measurements Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In thousands) Impaired loans $ 1,063 $ — $ — $ 1,063 Mortgage servicing rights 681 — — 681 $ 1,744 $ — $ — $ 1,744
Schedule of qualitative information for Level 3 assets measured at fair value on a non-recurring basis	The following table presents information for Level 3 assets measured at fair value on a non-recurring basis at December 31, 2020 and 2019: December 31, 2020 Fair Value Valuation Methodology Unobservable Inputs Range of Inputs Weighted Average (Dollars in thousands) Mortgage servicing rights $ 1,338 Estimated cash flow Prepayment speeds and discount rates (2) 9.7% - 26.2% 16.7% December 31, 2019 Fair Value Valuation Methodology Unobservable Inputs Range of Inputs Weighted Average (Dollars in thousands) Impaired loans $ 1,063 Estimated cash flow Expected value of future cash flows (1) —% —% Mortgage servicing rights 681 Estimated cash flow Prepayment speeds and discount rates (3) 3.6% - 24.0% 12.7% (1) Value based on management's estimate of expected future cash flows. (2) Value of SBA servicing rights based on a discount rate of 10.25%. (3) Value of SBA servicing rights based on a discount rate of 11.75%.
Schedule of fair value assets and liabilities on Consolidated Balance Sheets	The following tables present the assets and liabilities reported on the Consolidated Statements of Financial Condition at their fair values as of December 31, 2020 and 2019: December 31, 2020 Fair Value Measurements Carrying Value Total Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In thousands) Financial assets: Cash and cash equivalents $ 422,957 $ 422,957 $ 422,957 $ — $ — Debt securities available for sale 1,316,952 1,316,952 25,549 1,291,403 — Debt securities held to maturity 262,720 277,091 5,001 272,090 — Equity securities 5,418 5,418 5,072 346 Federal Home Loan Bank stock 43,759 43,759 — 43,759 — Loans receivable, net 6,107,094 6,394,524 — — 6,394,524 Derivative assets 19,425 19,425 — 19,425 — Financial liabilities: Deposits $ 6,778,624 $ 6,793,034 $ — $ 6,793,034 $ — Borrowings 799,364 808,853 — 808,853 — Derivative liabilities 42,384 42,384 — 42,384 — (17) Fair Value Measurements (continued) December 31, 2019 Fair Value Measurements Carrying Value Total Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In thousands) Financial assets: Cash and cash equivalents $ 75,547 $ 75,547 $ 75,547 $ — $ — Debt securities available for sale 1,098,336 1,098,336 42,386 1,055,950 — Debt securities held to maturity 285,756 289,505 19,960 269,545 — Equity securities 2,855 2,855 2,587 268 — Federal Home Loan Bank stock 69,579 69,579 — 69,579 — Loans receivable, net 6,135,857 6,219,008 — — 6,219,008 Derivative assets 185 185 — 185 — Financial liabilities: Deposits $ 5,645,842 $ 5,654,075 $ — $ 5,654,075 $ — Borrowings 1,407,022 1,411,962 — 1,411,962 — Derivative liabilities 11,546 11,546 — 11,546 —

Selected Quarterly Financial _2

Selected Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information	The following tables are a condensed summary of certain quarterly results of operations for the years ended December 31, 2020, 2019, and 2018: Quarters Ended December 31, 2020 March 31 June 30 September 30 December 31 (Dollars in thousands, except per share data) Total interest income $ 74,690 $ 75,587 $ 72,933 $ 72,501 Total interest expense 23,988 19,716 16,609 13,825 Net interest income 50,702 55,871 56,324 58,676 Provision for credit losses 9,568 5,736 2,516 627 Net interest income after provision for credit losses 41,134 50,135 53,808 58,049 Total non-interest income 6,391 7,008 7,909 9,962 Total non-interest expense 38,508 37,443 41,378 40,810 Income before income tax expense 9,017 19,700 20,339 27,201 Income tax expense 2,252 4,603 5,252 6,547 Net income $ 6,765 $ 15,097 $ 15,087 $ 20,654 Earnings per share - basic and diluted $ 0.06 $ 0.14 $ 0.14 $ 0.19 Weighted average shares outstanding - basic and diluted 108,438,173 111,102,306 110,983,871 108,499,658 Quarters Ended December 31, 2019 March 31 June 30 September 30 December 31 (Dollars in thousands, except per share data) Total interest income $ 62,887 $ 62,732 $ 64,438 $ 71,026 Total interest expense 20,503 21,889 22,722 23,598 Net interest income 42,384 40,843 41,716 47,428 Provision for loan losses 436 112 1,157 2,519 Net interest income after provision for loan losses 41,948 40,731 40,559 44,909 Total non-interest income 6,037 6,775 10,115 8,709 Total non-interest expense 29,559 31,841 31,064 36,237 Income before income tax expense 18,426 15,665 19,610 17,381 Income tax expense 3,507 3,634 5,392 3,832 Net income $ 14,919 $ 12,031 $ 14,218 $ 13,549 Earnings per share - basic and diluted $ 0.13 $ 0.11 $ 0.13 $ 0.12 Weighted average shares outstanding - basic and diluted 111,536,577 111,553,203 111,371,754 109,958,999 (18) Selected Quarterly Financial Data (Unaudited) (continued) Quarters Ended December 31, 2018 March 31 June 30 September 30 December 31 (Dollars in thousands, except per share data) Total interest income $ 51,791 $ 55,019 $ 57,695 $ 61,785 Total interest expense 12,730 14,004 17,112 18,410 Net interest income 39,061 41,015 40,583 43,375 Provision for loan losses 2,000 2,400 1,500 777 Net interest income after provision for loan losses 37,061 38,615 39,083 42,598 Total non-interest income 4,543 5,450 5,290 6,405 Total non-interest expense 26,015 61,768 26,590 31,013 Income (loss) before income tax expense 15,589 (17,703) 17,783 17,990 Income tax expense (benefit) 3,805 (2,961) 6,956 3,123 Net income (loss) $ 11,784 $ (14,742) $ 10,827 $ 14,867 Earnings per share - basic and diluted N/A $ (0.13) $ 0.10 $ 0.13 Weighted average shares outstanding - basic and diluted N/A 111,360,278 111,389,951 111,423,361

Earnings per Share (Tables)

Earnings per Share (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following is a reconciliation of the numerators and denominators of the basic and diluted earnings per share calculations for the years ended December 31, 2020, 2019,and 2018: December 31, 2020 2019 2018 (In thousands, except share and per share data) Net income $ 57,603 $ 54,717 $ 22,736 Shares: Weighted average shares outstanding - basic 109,755,924 111,101,246 111,395,723 Weighted average dilutive shares outstanding — — — Weighted average shares outstanding - diluted 109,755,924 111,101,246 111,395,723 Earnings per share: Basic $ 0.52 $ 0.49 $ 0.20 Diluted $ 0.52 $ 0.49 $ 0.20

Parent-only Financial Informa_2

Parent-only Financial Information (Tables)	12 Months Ended
	Dec. 31, 2020
Condensed Financial Information Disclosure [Abstract]
Condensed Balance Sheet	The condensed financial statements of Columbia Financial, Inc. (parent company) are presented below: Statements of Financial Condition December 31, 2020 2019 (In thousands) Assets Cash and due from banks $ 94,053 $ 168,242 Short-term investments 170 127 Total cash and cash equivalents 94,223 168,369 Debt securities available for sale, at fair value — 1,496 Equity securities, at fair value 1,167 1,282 Investment in subsidiaries 873,629 785,964 Loan receivable from Bank 41,461 42,982 Other assets 9,803 8,431 Total assets $ 1,020,283 $ 1,008,524 Liabilities and Stockholders' Equity Liabilities: Borrowings $ 6,953 $ 23,831 Accrued expenses and other liabilities 2,043 2,176 Total liabilities 8,996 26,007 Stockholders' equity 1,011,287 982,517 Total liabilities and stockholders' equity $ 1,020,283 $ 1,008,524
Condensed Statement of Comprehensive Income	Statements of Comprehensive Income (Loss) Years Ended December 31, 2020 2019 2018 (In thousands) Dividends from subsidiary $ 50,000 $ 179,000 $ — Interest income: Loans receivable 2,047 2,111 1,513 Debt securities available for sale and equity securities 51 51 123 Interest-earning deposits 1 173 871 Total interest income 52,099 181,335 2,507 Interest expense on borrowings 863 176 3,468 Net interest income (expense) 51,236 181,159 (961) Equity earnings (loss) in subsidiary 8,027 (123,142) 51,401 Non-interest income: Gain on securities transactions 2 236 — Change in fair value of equity securities (115) 65 — Other non-interest income — 139 — Total non-interest income (113) 440 — Non-interest expense: Charitable contribution to foundation — — 34,767 Merger-related expenses 280 1,807 — Other non-interest expense 1,377 1,955 425 Total non-interest expense 1,657 3,762 35,192 Income before income tax benefit 57,493 54,695 15,248 Income tax benefit 110 22 7,488 Net income 57,603 54,717 22,736 Other comprehensive income (loss) (890) 3,710 (6,487) Comprehensive income (loss) $ 56,713 $ 58,427 $ 16,249
Condensed Cash Flow Statement	Statements of Cash Flows Years Ended December 31, 2020 2019 2018 (In thousands) Cash flows from operating activities: Net income $ 57,603 $ 54,717 $ 22,736 Adjustments to reconcile net income to net cash provided by operating activities: Amortization of debt issuance costs — — 890 Amortization of intangible assets (278) (71) — Gain on securities transactions (2) (236) — Change in fair value of equity securities 115 (65) — Deferred tax expense (benefit) 1,411 1,453 (6,086) ( Increase) decrease in other assets (2,675) (2,026) 1,515 (Decrease) increase in accrued expenses and other liabilities (647) 3,515 (1,498) Contribution of common stock to Columbia Bank Foundation — — 34,767 Equity in undistributed (earnings) loss of subsidiary (8,027) 123,142 (51,401) Net cash provided by operating activities $ 47,500 $ 180,429 $ 923 Cash flows from investing activities: Capital contribution to subsidiary $ — $ — $ (246,420) Proceeds from sales of equity securities — 1,065 — Proceeds from paydowns/maturities/calls of debt securities available for sale 1,498 500 1,601 Purchases of debt securities available for sale — — (414) Purchases of equity securities — (416) — Loan to ESOP — — (45,428) Repayment of loan receivable from Bank 1,521 1,457 989 Net cash paid in acquisition — (135,410) — Net cash provided by (used in) investing activities $ 3,019 $ (132,804) $ (289,672) Cash flows from financing activities: Payments of subordinated debt and trust preferred securities $ (16,600) $ — $ (51,547) Issuance of common stock in initial public offering — — 492,428 Purchase of treasury stock (108,166) (55,309) — Issuance of common stock allocated to restricted stock award grants — 21,687 — Restricted stock forfeitures (199) (736) — Repurchase of shares for taxes (181) — — Issuance of treasury stock allocated to restricted stock award grants 481 1,269 — Net cash (used in) provided by financing activities $ (124,665) $ (33,089) $ 440,881 (20) Parent-only Financial Information (continued) Statements of Cash Flows Years Ended December 31, 2020 2019 2018 (In thousands) Net (decrease) increase in cash and cash equivalents $ (74,146) $ 14,536 $ 152,132 Cash and cash equivalents at beginning of year 168,369 153,833 1,701 Cash and cash equivalents at end of period $ 94,223 $ 168,369 $ 153,833 Acquisition: Non-cash assets acquired: Debt securities available for sale $ — $ 1,998 $ — Equity securities — 208 — Other assets — 1,492 — Total non-cash assets acquired $ — $ 3,698 $ — Liabilities assumed: Borrowings $ — $ 23,901 $ — Total liabilities assumed $ — $ 23,901 $ — Net non-cash liabilities acquired $ — $ (20,203) $ — Net cash and cash equivalents acquired in acquisitions $ — $ 884 $ —

Other Comprehensive Income (L_2

Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Schedule of Other Comprehensive Income (Loss)	The following tables present the components of other comprehensive income (loss), both gross and net of tax, for the years ended December 31, 2020, 2019, and 2018: For the Years Ended December 31, 2020 2019 Before Tax Tax Effect After Tax Before Tax Tax Effect After Tax (In thousands) Components of other comprehensive income (loss): Unrealized gains on debt securities available for sale: $ 26,876 $ (5,640) $ 21,236 $ 26,601 $ (5,534) $ 21,067 Accretion of unrealized gain on debt securities reclassified as held to maturity 160 (34) 126 11 (2) 9 Reclassification adjustment for gains included in net income 370 (81) 289 2,612 (601) 2,011 27,406 (5,755) 21,651 29,224 (6,137) 23,087 Derivatives: Unrealized (loss) on swap contracts accounted for as cash flow hedges (10,605) 2,223 (8,382) (8,193) 1,725 (6,468) Employee benefit plans: Amortization of prior service cost included in net income (56) 12 (44) (56) 12 (44) Reclassification adjustment of actuarial net (loss) included in net income (4,284) 900 (3,384) (3,709) 779 (2,930) Change in funded status of retirement obligations (13,583) 2,852 (10,731) (12,576) 2,641 (9,935) (17,923) 3,764 (14,159) (16,341) 3,432 (12,909) Total other comprehensive (loss) income $ (1,122) $ 232 $ (890) $ 4,690 $ (980) $ 3,710 (21) Other Comprehensive Income (Loss) (continued) For the Year Ended December 31, 2018 Before Tax Tax Effect After Tax (In thousands) Components of other comprehensive(loss) income: Unrealized (losses) on debt securities available for sale: $ (7,224) $ 1,446 $ (5,778) Accretion of unrealized (loss) on debt securities reclassified as held to maturity (13) — (13) Reclassification adjustment for (losses) included in net income (116) 24 (92) (7,353) 1,470 (5,883) Derivatives: Unrealized (loss)on swap contracts accounted for as cash flow hedges (2,825) 595 (2,230) Employee benefit plans: Amortization of prior service cost included in net income (623) 132 (491) Reclassification adjustment of actuarial net loss included in net income 2,526 (530) 1,996 Change in funded status of retirement obligations 897 (776) 121 2,800 (1,174) 1,626 Total other comprehensive (loss) income $ (7,378) $ 891 $ (6,487)
Components of Other Comprehensive Income (Loss)	The following tables present the changes in the components of accumulated other comprehensive income (loss), net of tax, for the years ended December 31, 2020, 2019, and 2018: For the Years Ended December 31, 2020 2019 Unrealized Gains on Debt Securities Available for Sale Unrealized (Losses) on Swaps Employee Benefit Plans Accumulated Other Comprehensive (Loss) Unrealized (Losses) Gains on Debt Securities Available for Sale Unrealized (Losses) on Swaps Employee Benefit Plans Accumulated Other Comprehensive (Loss) (In thousands) Balance at beginning of period $ 9,377 $ (8,474) $ (69,638) $ (68,735) $ (13,162) $ (2,006) $ (56,729) $ (71,897) Effect of the adoption of ASU 2016-01 — — (548) — — (548) Balance at January 1, $ 9,377 $ (8,474) $ (69,638) $ (68,735) $ (13,710) $ (2,006) $ (56,729) $ (72,445) Current period changes in other comprehensive income (loss) 21,651 (8,382) (14,159) (890) 23,087 (6,468) (12,909) 3,710 Total other comprehensive income (loss) $ 31,028 $ (16,856) $ (83,797) $ (69,625) $ 9,377 $ (8,474) $ (69,638) $ (68,735) For the Year Ended December 31, 2018 Unrealized (Losses) on Debt Securities Available for Sale Unrealized Gains (Losses) on Swaps Employee Benefit Plans Accumulated Other Comprehensive (Loss) (In thousands) Balance at beginning of period $ (7,279) $ 224 $ (58,355) $ (65,410) Current period changes in other comprehensive (loss) income (5,883) (2,230) 1,626 (6,487) Total other comprehensive (loss) $ (13,162) $ (2,006) $ (56,729) $ (71,897)
Reclassification out of AOCI	The following tables reflect amounts reclassified from accumulated other comprehensive income (loss) in the Consolidated Statements of Income and the affected line item in the statement where net income is presented for the years ended December 31, 2020, 2019, and 2018: Accumulated Other Comprehensive (Loss) Income Components For the Years Ended December 31, Affected line items in the Consolidated Statements of Income 2020 2019 2018 (In thousands) Reclassification adjustment for gains (losses) included in net income $ 370 $ 2,612 $ (116) Gain (loss) on securities transactions Reclassification adjustment of actuarial net (loss) gain included in net income (4,284) (3,709) 2,526 Other non-interest expense Total before tax (3,914) (1,097) 2,410 Income (tax) benefit 819 178 (506) Net of tax $ (3,095) $ (919) $ 1,904

Derivatives and Hedging Activ_2

Derivatives and Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of derivative financial instruments on the Consolidated Balance Sheets	The tables below present the fair value of the Company’s derivative financial instruments as well as their classification in the Consolidated Statements of Financial Condition at December 31, 2020 and 2019: December 31, 2020 Asset Derivative Liability Derivative Consolidated Statements of Financial Condition Fair Value Consolidated Statements of Financial Condition Fair Value (In thousands) Derivatives: Interest rate swaps Other Assets $ 19,425 Other Liabilities $ 42,384 Total derivative instruments $ 19,425 $ 42,384 December 31, 2019 Asset Derivative Liability Derivative Consolidated Statements of Financial Condition Fair Value Consolidated Statements of Financial Condition Fair Value (In thousands) Derivatives: Interest rate swaps Other Assets $ 185 Other Liabilities $ 11,546 Total derivative instruments $ 185 $ 11,546

Revenue Recognition (Tables)

Revenue Recognition (Tables)	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table presents non-interest income, segregated by revenue streams in-scope and out-of-scope of Topic 606, for the years ended December 31, 2020, 2019, and 2018. For the Years Ended December 31, 2020 2019 2018 (In thousands) Non-interest income In-scope of Topic 606: Demand deposit account fees $ 3,633 $ 4,478 $ 3,987 Title insurance fees 5,034 4,981 4,297 Other non-interest income 6,472 4,844 4,679 Total in-scope non-interest income 15,139 14,303 12,963 Total out-of-scope non-interest income 16,131 17,333 8,725 Total non-interest income $ 31,270 $ 31,636 $ 21,688

Business (Details)

Business (Details) - USD ($) $ / shares in Units, $ in Thousands	Apr. 01, 2020	Nov. 01, 2019	Apr. 19, 2018
Stewardship Financial Corporation
Subsidiary, Sale of Stock [Line Items]
Business acquisition, share price (in dollars per share)		$ 15.75
Cash paid for purchase		$ 136,294
Roselle Entities
Subsidiary, Sale of Stock [Line Items]
Business, acquisition, equity interest issued or issuable (in shares)	4,759,048
Columbia Bank, MHC
Subsidiary, Sale of Stock [Line Items]
Shares issued (in shares)			62,580,155,000
Columbia Bank Foundation
Subsidiary, Sale of Stock [Line Items]
Shares issued (in shares)			3,476,675,000
Columbia Bank Employee Stock Ownership Plan
Subsidiary, Sale of Stock [Line Items]
Shares issued (in shares)			49,832,345,000

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) - USD ($)	1 Months Ended	12 Months Ended
	Apr. 30, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Nov. 30, 2019	Jul. 31, 2018	Dec. 31, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Proceeds from sales of loans held-for-sale		$ 111,764,000	$ 101,946,000	$ 3,615,000
Junior subordinated debenture owed to unconsolidated subsidiary trust						$ 51,500,000
Assets		8,798,536,000	8,188,694,000
Cash reserves		4,900,000	8,800,000
Loan threshold for individual evaluation for impairment		500,000
Equity securities, at fair value		5,418,000	2,855,000
Stockholders' equity		1,011,287,000	982,517,000	972,060,000			$ 472,070,000
Variable Interest Entity, Not Primary Beneficiary
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Assets					$ 7,000,000
Cumulative Effect, Period of Adoption, Adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Stockholders' equity				0
Retained Earnings
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Stockholders' equity		$ 673,084,000	615,481,000	560,216,000			$ 537,480,000
Retained Earnings | Cumulative Effect, Period of Adoption, Adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Stockholders' equity				548,000
Buildings
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Property, plant and equipment, useful life		40 years
Minimum
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Defined contribution plan, employer matching contribution, percent of match		3.00%
Minimum | Land and building improvements
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Property, plant and equipment, useful life		10 years
Minimum | Furniture and equipment
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Property, plant and equipment, useful life		3 years
Maximum
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Defined contribution plan, employer matching contribution, percent of match		4.50%
Maximum | Land and building improvements
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Property, plant and equipment, useful life		20 years
Maximum | Furniture and equipment
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Property, plant and equipment, useful life		10 years
Accounting Standards Update 2016-01 | Cumulative Effect, Period of Adoption, Adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Equity securities, at fair value			1,900,000
Accounting Standards Update 2016-01 | Retained Earnings | Cumulative Effect, Period of Adoption, Adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Stockholders' equity			548,000	$ 548,000
Columbia Financial Capital Trust I
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Ownership percentage by parent						100.00%
Stewardship Statutory Trust I
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Ownership percentage by parent					100.00%
Columbia Bank Employee Stock Ownership Plan
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Loan term	20 years	20 years
Stewardship Property
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Assets held-for-sale, long-lived, fair value disclosure		$ 1,900,000	$ 1,800,000

Acquisitions - Narrative (Detai

Acquisitions - Narrative (Details)	Apr. 01, 2020USD ($)shares	Nov. 01, 2019USD ($)branch$ / shares	Dec. 31, 2020USD ($)branch	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Business Acquisition [Line Items]
Assets			$ 8,798,536,000	$ 8,188,694,000
Loans receivable, net			6,107,094,000	6,135,857,000
Liabilities			7,787,249,000	7,206,177,000
Deposits			6,778,624,000	5,645,842,000
Balance			799,364,000	1,407,022,000
Merger-related expenses			1,931,000	2,755,000	$ 0
Goodwill			$ 80,285,000	60,763,000
Facility Closing
Business Acquisition [Line Items]
Number of branches closed | branch			4
Gain (loss) on restructuring			$ 770,000
Stewardship Financial Corporation
Business Acquisition [Line Items]
Business acquisition, share price (in dollars per share) | $ / shares		$ 15.75
Merger-related expenses			1,300,000	2,800,000
Goodwill		$ 55,047,000
Roselle Entities
Business Acquisition [Line Items]
Merger-related expenses			597,000	$ 0
Goodwill	$ 23,809,000		18,700,000
Business, acquisition, equity interest issued or issuable (in shares) | shares	4,759,048
Business combination, provisional information, initial accounting incomplete, adjustment, deferred tax assets			$ 5,100,000
Stewardship Financial Corporation
Business Acquisition [Line Items]
Assets		956,000,000
Loans receivable, net		756,900,000
Securities		52,600,000
Liabilities		877,800,000
Deposits		781,400,000
Balance		$ 81,800,000
Number of stores | branch		12
Core Deposits
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, weighted average useful life			10 years
Core Deposits | Stewardship Financial Corporation
Business Acquisition [Line Items]
Core deposit intangible		$ 7,500,000
Leasehold Improvements and Equipment | Minimum
Business Acquisition [Line Items]
Property, plant and equipment, useful life			3 years
Leasehold Improvements and Equipment | Maximum
Business Acquisition [Line Items]
Property, plant and equipment, useful life			10 years

Acquisitions - Assets Acquired

Acquisitions - Assets Acquired and Liabilities Assumed in the Stewardship Acquisition (Details) - USD ($) $ in Thousands	Nov. 01, 2019	Dec. 31, 2020	Dec. 31, 2019
Liabilities assumed:
Goodwill		$ 80,285	$ 60,763
Stewardship Financial Corporation
Assets acquired:
Cash and cash equivalents	$ 105,006
Debt securities available for sale	51,710
Equity securities	1,073
Federal Home Loan Bank stock	3,716
Loans receivable	757,223
Accrued interest receivable	2,239
Office properties and equipment, net	6,815
Bank-owned life insurance	22,096
Deferred tax assets, net	3,534
Core deposit and other intangibles	7,467
Other assets	767
Total assets acquired	961,646
Liabilities assumed:
Deposits	782,698
Borrowings	82,761
Advance payments by borrowers for taxes and insurance	356
Accrued expenses and other liabilities	14,584
Total liabilities assumed	880,399
Net assets acquired	81,247
Cash paid for purchase	136,294
Goodwill	$ 55,047

Acquisitions - Assets Acquire_2

Acquisitions - Assets Acquired and Liabilities Assumed in Roselle Acquisition (Details) - USD ($) $ in Thousands	Apr. 01, 2020	Dec. 31, 2020	Dec. 31, 2019
Liabilities assumed:
Goodwill		$ 80,285	$ 60,763
Roselle Entities
Assets acquired:
Cash and cash equivalents	$ 155,248
Debt securities available for sale	51,479
Debt securities held to maturity	13,418
Equity securities	1,796
Federal Home Loan Bank stock	2,010
Loans receivable	171,593
Accrued interest receivable	679
Office properties and equipment, net	5,774
Bank-owned life insurance	17,245
Deferred tax assets, net	1,334
Other assets	1,489
Total assets acquired	422,065
Liabilities assumed:
Deposits	333,234
Borrowings	37,728
Advance payments by borrowers for taxes and insurance	982
Accrued expenses and other liabilities	5,400
Total liabilities assumed	377,344
Net assets acquired	44,721
Fair market value of stock issued to Columbia Bank MHC for purchase	68,530
Goodwill	$ 23,809	$ 18,700

Debt Securities Available for_3

Debt Securities Available for Sale - Securities Available-for-Sale (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 1,277,511	$ 1,086,143
Gross Unrealized Gains	40,748	14,248
Gross Unrealized (Losses)	(1,307)	(2,055)
Fair Value	1,316,952	1,098,336
U.S. government and agency obligations
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	24,425	42,081
Gross Unrealized Gains	1,124	321
Gross Unrealized (Losses)	0	(16)
Fair Value	25,549	42,386
Mortgage-backed securities and collateralized mortgage obligations
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,163,613	968,165
Gross Unrealized Gains	37,343	12,981
Gross Unrealized (Losses)	(562)	(1,265)
Fair Value	1,200,394	979,881
Municipal obligations
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	16,845	2,284
Gross Unrealized Gains	17	1
Gross Unrealized (Losses)	0	(1)
Fair Value	16,862	2,284
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	67,628	68,613
Gross Unrealized Gains	2,264	945
Gross Unrealized (Losses)	(415)	(378)
Fair Value	69,477	69,180
Trust preferred securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	5,000	5,000
Gross Unrealized Gains	0	0
Gross Unrealized (Losses)	(330)	(395)
Fair Value	$ 4,670	$ 4,605

Debt Securities Available for_4

Debt Securities Available for Sale - Expected Maturities of Available-for-Sale Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Amortized Cost
Amortized Cost	$ 1,277,511	$ 1,086,143
Fair Value
Fair Value	1,316,952	1,098,336
Debt Securities excluding Mortgage-based securities and CMOs
Amortized Cost
One year or less	21,378
More than one year to five years	47,429
More than five years to ten years	45,091
Amortized Cost	113,898
Fair Value
One year or less	21,380
More than one year to five years	49,276
More than five years to ten years	45,902
Fair Value	116,558
Mortgage-backed securities and collateralized mortgage obligations
Amortized Cost
Amortized Cost	1,163,613	968,165
Fair Value
Fair Value	$ 1,200,394	$ 979,881

Debt Securities Available for_5

Debt Securities Available for Sale - Narrative (Details)	12 Months Ended
	Dec. 31, 2020USD ($)security	Dec. 31, 2019USD ($)security	Dec. 31, 2018USD ($)
Debt Securities, Available-for-sale [Line Items]
Amortized cost	$ 1,277,511,000	$ 1,086,143,000
Debt securities available for sale, at fair value	1,316,952,000	1,098,336,000
Proceeds from sales of debt securities available for sale	20,761,000	65,198,000	$ 11,513,000
Debt securities, available-for-sale securities, gross realized gains	369,000	2,200,000	116,000
Debt securities, available-for-sale, realized loss	0	22,000	0
Proceeds from calls and maturities of debt securities, available-for-sale	11,600,000	24,100,000	11,500,000
Calls of debt securities, available-for-sale, realized gain	1,000	174,000
Calls of debt securities, available-for-sale, unrealized loss	0	0
Proceeds from sale and maturity of debt securities, available for sale	10,900,000	$ 797,000	2,400,000
Debt securities, available-for-sale, number of matured debt securities | security		1
Debt securities, available-for-sale, restricted	$ 822,200,000	$ 462,000,000
Number of unrealized loss positions | security	40	97
Other-than-temporary impairment loss, debt securities, available for sale	$ 0	$ 0	$ 0
Mortgage-backed securities and collateralized mortgage obligations
Debt Securities, Available-for-sale [Line Items]
Amortized cost	1,163,613,000	968,165,000
Debt securities available for sale, at fair value	$ 1,200,394,000	$ 979,881,000

Debt Securities Available for_6

Debt Securities Available for Sale - Continuous Unrealized Loss Position of Available-for-Sale Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Less Than 12 Months
Fair Value	$ 127,823	$ 187,055
Gross Unrealized (Losses)	(636)	(965)
12 Months or Longer
Fair Value	34,428	72,428
Gross Unrealized (Losses)	(671)	(1,090)
Total
Fair Value	162,251	259,483
Gross Unrealized (Losses)	(1,307)	(2,055)
U.S. government and agency obligations
Less Than 12 Months
Fair Value		5,106
Gross Unrealized (Losses)		(13)
12 Months or Longer
Fair Value		4,988
Gross Unrealized (Losses)		(3)
Total
Fair Value		10,094
Gross Unrealized (Losses)		(16)
Mortgage-backed securities and collateralized mortgage obligations
Less Than 12 Months
Fair Value	117,978	178,665
Gross Unrealized (Losses)	(481)	(946)
12 Months or Longer
Fair Value	24,018	58,208
Gross Unrealized (Losses)	(81)	(319)
Total
Fair Value	141,996	236,873
Gross Unrealized (Losses)	(562)	(1,265)
Municipal obligations
Less Than 12 Months
Fair Value		696
Gross Unrealized (Losses)		(1)
12 Months or Longer
Fair Value		0
Gross Unrealized (Losses)		0
Total
Fair Value		696
Gross Unrealized (Losses)		(1)
Corporate debt securities
Less Than 12 Months
Fair Value	9,845	2,588
Gross Unrealized (Losses)	(155)	(5)
12 Months or Longer
Fair Value	5,740	4,627
Gross Unrealized (Losses)	(260)	(373)
Total
Fair Value	15,585	7,215
Gross Unrealized (Losses)	(415)	(378)
Trust preferred securities
Less Than 12 Months
Fair Value	0	0
Gross Unrealized (Losses)	0	0
12 Months or Longer
Fair Value	4,670	4,605
Gross Unrealized (Losses)	(330)	(395)
Total
Fair Value	4,670	4,605
Gross Unrealized (Losses)	$ (330)	$ (395)

Debt Securities Held-to-Maturit

Debt Securities Held-to-Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 262,720	$ 285,756
Gross Unrealized Gains	14,373	4,074
Gross Unrealized (Losses)	(2)	(325)
Fair Value	277,091	289,505
U.S. government and agency obligations
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	5,000	20,000
Gross Unrealized Gains	1	26
Gross Unrealized (Losses)	0	(66)
Fair Value	5,001	19,960
Mortgage-backed securities and collateralized mortgage obligations
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	257,720	265,756
Gross Unrealized Gains	14,372	4,048
Gross Unrealized (Losses)	(2)	(259)
Fair Value	$ 272,090	$ 269,545

Debt Securities Held to Matur_3

Debt Securities Held to Maturity - Expected Maturities of Held-to-Maturity Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Amortized cost
More than one year to five years	$ 5,000
Amortized Cost	262,720	$ 285,756
Fair value
More than one year to five years	5,001
Debt securities held to maturity	277,091	289,505
Mortgage-backed securities and collateralized mortgage obligations
Amortized cost
Mortgage-backed securities and collateralized mortgage obligations	257,720
Amortized Cost	257,720	265,756
Fair value
Mortgage-backed securities and collateralized mortgage obligations	272,090
Debt securities held to maturity	$ 272,090	$ 269,545

Debt Securities Held to Matur_4

Debt Securities Held to Maturity - Narrative (Details)	12 Months Ended
	Dec. 31, 2020USD ($)security	Dec. 31, 2019USD ($)security	Dec. 31, 2018USD ($)
Schedule of Held-to-maturity Securities [Line Items]
Debt securities, held-to-maturity, amortized cost	$ 262,720,000	$ 285,756,000
Debt securities, held-to-maturity, fair value	277,091,000	289,505,000
Proceeds from sale of held-to-maturity securities	0	0	$ 0
Proceeds from calls and maturities of debt securities held to maturity	20,000,000	33,400,000	5,400,000
Debt securities, held-to-maturity, realized gain	0		0
Debt securities, held-to-maturity, sold, realized gain		24,000
Debt securities, held-to-maturity, sold, realized loss		0
Securities available-for-sale sold under agreements	$ 220,500,000	$ 236,000,000
Number of unrealized loss positions | security	2	22
Other-than-temporary impairment loss, debt securities, held-to-maturity, before tax	$ 0	$ 0	$ 0
Mortgage-backed securities and collateralized mortgage obligations
Schedule of Held-to-maturity Securities [Line Items]
Debt securities, held-to-maturity, amortized cost	257,720,000	265,756,000
Debt securities, held-to-maturity, fair value	$ 272,090,000	$ 269,545,000

Debt Securities Held to Matur_5

Debt Securities Held to Maturity - Continuous Unrealized Loss Position of Held-to-Maturity Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Less Than 12 Months
Fair Value	$ 2,176	$ 37,845
Gross Unrealized (Losses)	(2)	(317)
12 Months or Longer
Fair Value	0	772
Gross Unrealized (Losses)	0	(8)
Total
Fair Value	2,176	38,617
Gross Unrealized (Losses)	$ (2)	(325)
U.S. government and agency obligations
Less Than 12 Months
Fair Value		9,934
Gross Unrealized (Losses)		(66)
12 Months or Longer
Fair Value		0
Gross Unrealized (Losses)		0
Total
Fair Value		9,934
Gross Unrealized (Losses)		(66)
Mortgage-backed securities and collateralized mortgage obligations
Less Than 12 Months
Fair Value		27,911
Gross Unrealized (Losses)		(251)
12 Months or Longer
Fair Value		772
Gross Unrealized (Losses)		(8)
Total
Fair Value		28,683
Gross Unrealized (Losses)		$ (259)

Equity Securities at Fair Val_2

Equity Securities at Fair Value - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt and Equity Securities, FV-NI [Line Items]
Equity securities, at fair value	$ 5,418,000	$ 2,855,000
Stockholders' equity	1,011,287,000	982,517,000	$ 972,060,000	$ 472,070,000
Increase (decrease) in fair value of equity securities	767,000	305,000	0
Proceeds from sale of equity securities	0	1,100,000
Gross realized gain in equity securities		236,000
Gross realized losses in equity securities		0
Cumulative Effect, Period of Adoption, Adjustment
Debt and Equity Securities, FV-NI [Line Items]
Stockholders' equity			0
Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2016-01
Debt and Equity Securities, FV-NI [Line Items]
Equity securities, at fair value		1,900,000
Retained Earnings
Debt and Equity Securities, FV-NI [Line Items]
Stockholders' equity	673,084,000	615,481,000	560,216,000	537,480,000
Retained Earnings | Cumulative Effect, Period of Adoption, Adjustment
Debt and Equity Securities, FV-NI [Line Items]
Stockholders' equity			548,000
Retained Earnings | Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2016-01
Debt and Equity Securities, FV-NI [Line Items]
Stockholders' equity		548,000	548,000
Accumulated Other Comprehensive (Loss)
Debt and Equity Securities, FV-NI [Line Items]
Stockholders' equity	$ (69,625,000)	$ (68,735,000)	(71,897,000)	$ (65,410,000)
Accumulated Other Comprehensive (Loss) | Cumulative Effect, Period of Adoption, Adjustment
Debt and Equity Securities, FV-NI [Line Items]
Stockholders' equity			(548,000)
Accumulated Other Comprehensive (Loss) | Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2016-01
Debt and Equity Securities, FV-NI [Line Items]
Stockholders' equity			$ (548,000)

Loans Receivable and Allowanc_3

Loans Receivable and Allowance for Loan Losses - Loans Receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	$ 6,168,892	$ 6,176,329
Net deferred loan costs, fees and purchased premiums and discounts	12,878	21,237
Loans receivable	6,181,770	6,197,566
Real estate loans | One-to-four family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	1,940,636	2,077,508
Real estate loans | Multifamily and commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	2,822,858	2,924,851
Real estate loans | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	328,711	298,942
Commercial business loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	754,013	484,941
Consumer loans | Home equity loans and advances
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	321,177	388,127
Consumer loans | Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	1,497	1,960
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	6,162,547	6,169,308
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | One-to-four family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	1,940,327	2,077,079
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Multifamily and commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	2,817,965	2,919,985
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	328,711	298,942
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Commercial business loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	752,870	483,215
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Home equity loans and advances
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	321,177	388,127
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	1,497	1,960
Financial Asset Acquired with Credit Deterioration
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	6,345	7,021
Financial Asset Acquired with Credit Deterioration | Real estate loans | One-to-four family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	309	429
Financial Asset Acquired with Credit Deterioration | Real estate loans | Multifamily and commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	4,893	4,866
Financial Asset Acquired with Credit Deterioration | Real estate loans | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	0	0
Financial Asset Acquired with Credit Deterioration | Commercial business loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	1,143	1,726
Financial Asset Acquired with Credit Deterioration | Consumer loans | Home equity loans and advances
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	0	0
Financial Asset Acquired with Credit Deterioration | Consumer loans | Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross loans	$ 0	$ 0

Loans Receivable and Allowanc_4

Loans Receivable and Allowance for Loan Losses - Narrative (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2020loan	Dec. 31, 2020USD ($)loan	Dec. 31, 2019USD ($)loan	Dec. 31, 2018USD ($)loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-for-sale		$ 4,100,000	$ 0
Proceeds from sales of loans held-for-sale		111,764,000	101,946,000	$ 3,615,000
Gain on sale of loans held-for-sale			718,000
Loss on sale of loans held-for-sale			0
Gain on sale of loans held-for-investment		161,000	67,000
Loss on sale of loans held-for-investment		0	0
Purchases and grants of loans receivable		0	89,774,000	32,251,000
Loans receivable		6,181,770,000	6,197,566,000
Carrying value of servicing liability		598,000,000	526,300,000
Servicing income		1,400,000	1,200,000	1,100,000
Proceeds from sales of loans receivable		$ 35,613,000	$ 11,671,000	32,039,000
Threshold period, past due status of financing receivables		30 days
Threshold period, past due for nonperforming status of financing receivables		90 days	90 days
Non-accrual loans		$ 8,200,000	$ 6,700,000
Increase in interest income if non-accrual had performed in line with their original terms		426,000	509,000	126,000
Cash basis interest income on non-accrual loans		410,000	437,000	89,000
Loans past due		0	0
Property acquired through foreclosure		$ 0	$ 0
Number of loans in the process of foreclosure | loan		2	4
Loans in process of foreclosure		$ 398,000	$ 522,000
Loan threshold for individual evaluation for impairment		500,000
Specific allowance for loan losses attributable to impaired loans		1,088,000	1,621,000
Impaired loans for which there are no related allowance for loan losses		19,061,000	10,747,000
Investment in troubled debt restructuring		$ 45,400,000	$ 20,000,000	$ 16,000,000
Number of loans in troubled debt restructuring | loan		7	1	7
Less Than 90 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans		$ 2,200,000	$ 1,500,000
Number of loans in non-accrual status | loan	8	19
90 Days or More
Accounts, Notes, Loans and Financing Receivable [Line Items]
Investment in troubled debt restructuring		$ 91,000		$ 101,000
Number of loans in troubled debt restructuring | loan		1	0	1
30-59 Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Investment in troubled debt restructuring		$ 11,900,000	$ 660,000	$ 1,000,000
Number of loans in troubled debt restructuring | loan		3	3	7
Related Parties
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchases and grants of loans receivable		$ 300,000	$ 0	$ 0
Loans receivable		$ 1,600,000	1,100,000
Number of loans granted to related party | loan		1
Freddie Mac
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales of loans receivable		$ 117,300,000	21,600,000	0
Gain on sale of loans receivable		3,500,000
Loss on sale of loans receivable		0
Real estate loans | One-to-four family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales of loans held-for-sale		111,800,000	97,400,000	3,600,000
Gain on sale of loans held-for-sale		1,700,000
Loss on sale of loans held-for-sale		0
Gain (loss) on sale of loans held-for-sale				0
Proceeds from sale of loans held-for-investment		15,100,000	5,300,000	32,000,000
Gain on sale of loans held-for-investment				618,000
Loss on sale of loans held-for-investment				$ 0
Purchases and grants of loans receivable			89,800,000
Specific allowance for loan losses attributable to impaired loans		391,000	484,000
Impaired loans for which there are no related allowance for loan losses		3,344,000	4,314,000
Number of loans in troubled debt restructuring | loan				5
Real estate loans | Multifamily and commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales of loans held-for-sale			4,300,000
Proceeds from sale of loans held-for-investment			5,500,000
Purchases and grants of loans receivable				$ 32,300,000
Specific allowance for loan losses attributable to impaired loans		601,000	2,000
Impaired loans for which there are no related allowance for loan losses		$ 13,058,000	$ 1,494,000
Number of loans in troubled debt restructuring | loan		5	0	1
Real estate loans | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sale of loans held-for-investment		$ 13,000,000
Commercial business loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales of loans held-for-sale			$ 164,000
Proceeds from sale of loans held-for-investment		7,600,000	901,000
Specific allowance for loan losses attributable to impaired loans		84,000	1,121,000
Impaired loans for which there are no related allowance for loan losses		$ 1,945,000	$ 3,859,000
Number of loans in troubled debt restructuring | loan		2	1
Commercial business loans | Paycheck Protection Program
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable		$ 344,400,000	$ 0
Financing receivable, unamortized loan fee (cost)		$ 6,600,000

Loans Receivable and Allowanc_5

Loans Receivable and Allowance for Loan Losses - Aging of Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Non-accrual	$ 8,200	$ 6,700
Total	6,168,892	6,176,329
Real estate loans | One-to-four family
Financing Receivable, Past Due [Line Items]
Total	1,940,636	2,077,508
Real estate loans | Multifamily and commercial
Financing Receivable, Past Due [Line Items]
Total	2,822,858	2,924,851
Real estate loans | Construction
Financing Receivable, Past Due [Line Items]
Total	328,711	298,942
Commercial business loans
Financing Receivable, Past Due [Line Items]
Total	754,013	484,941
Consumer loans | Home equity loans and advances
Financing Receivable, Past Due [Line Items]
Total	321,177	388,127
Consumer loans | Other consumer loans
Financing Receivable, Past Due [Line Items]
Total	1,497	1,960
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Past Due [Line Items]
Total Past Due	31,416	18,478
Non-accrual	8,156	6,687
Current	6,122,975	6,144,143
Total	6,162,547	6,169,308
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | 30-59 Days
Financing Receivable, Past Due [Line Items]
Total Past Due	22,766	9,642
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | 60-89 Days
Financing Receivable, Past Due [Line Items]
Total Past Due	2,664	3,588
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | 90 Days or More
Financing Receivable, Past Due [Line Items]
Total Past Due	5,986	5,248
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | One-to-four family
Financing Receivable, Past Due [Line Items]
Total Past Due	5,881	10,019
Non-accrual	2,637	1,732
Current	1,931,809	2,065,328
Total	1,940,327	2,077,079
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | One-to-four family | 30-59 Days
Financing Receivable, Past Due [Line Items]
Total Past Due	3,068	6,249
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | One-to-four family | 60-89 Days
Financing Receivable, Past Due [Line Items]
Total Past Due	912	2,132
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | One-to-four family | 90 Days or More
Financing Receivable, Past Due [Line Items]
Total Past Due	1,901	1,638
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Multifamily and commercial
Financing Receivable, Past Due [Line Items]
Total Past Due	16,883	2,552
Non-accrual	1,873	716
Current	2,799,209	2,916,717
Total	2,817,965	2,919,985
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Multifamily and commercial | 30-59 Days
Financing Receivable, Past Due [Line Items]
Total Past Due	15,645	626
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Multifamily and commercial | 60-89 Days
Financing Receivable, Past Due [Line Items]
Total Past Due	0	1,210
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Multifamily and commercial | 90 Days or More
Financing Receivable, Past Due [Line Items]
Total Past Due	1,238	716
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Construction
Financing Receivable, Past Due [Line Items]
Total Past Due	550	0
Non-accrual	0	0
Current	328,161	298,942
Total	328,711	298,942
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Construction | 30-59 Days
Financing Receivable, Past Due [Line Items]
Total Past Due	550	0
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Construction | 60-89 Days
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Construction | 90 Days or More
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Commercial business loans
Financing Receivable, Past Due [Line Items]
Total Past Due	5,852	3,545
Non-accrual	2,968	3,686
Current	744,050	475,984
Total	752,870	483,215
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Commercial business loans | 30-59 Days
Financing Receivable, Past Due [Line Items]
Total Past Due	2,343	1,056
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Commercial business loans | 60-89 Days
Financing Receivable, Past Due [Line Items]
Total Past Due	1,056	0
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Commercial business loans | 90 Days or More
Financing Receivable, Past Due [Line Items]
Total Past Due	2,453	2,489
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Home equity loans and advances
Financing Receivable, Past Due [Line Items]
Total Past Due	2,246	2,359
Non-accrual	678	553
Current	318,253	385,215
Total	321,177	388,127
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Home equity loans and advances | 30-59 Days
Financing Receivable, Past Due [Line Items]
Total Past Due	1,156	1,708
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Home equity loans and advances | 60-89 Days
Financing Receivable, Past Due [Line Items]
Total Past Due	696	246
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Home equity loans and advances | 90 Days or More
Financing Receivable, Past Due [Line Items]
Total Past Due	394	405
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Other consumer loans
Financing Receivable, Past Due [Line Items]
Total Past Due	4	3
Non-accrual	0	0
Current	1,493	1,957
Total	1,497	1,960
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Other consumer loans | 30-59 Days
Financing Receivable, Past Due [Line Items]
Total Past Due	4	3
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Other consumer loans | 60-89 Days
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Other consumer loans | 90 Days or More
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 0	$ 0

Loans Receivable and Allowanc_6

Loans Receivable and Allowance for Loan Losses - PCI Loans Acquired (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Apr. 01, 2020	Dec. 31, 2019	Nov. 01, 2019	Dec. 31, 2018
Receivables [Abstract]
Contractually required principal and interest		$ 461		$ 9,286
Contractual cash flows not expected to be collected (non-accretable difference)		(237)		(1,823)
Expected cash flows to be collected		224		7,463
Interest component of expected cash flows (accretable yield)	$ 418	(51)	$ 511	(556)	$ 0
Fair value of acquired loans		$ 173		$ 6,907

Loans Receivable and Allowanc_7

Loans Receivable and Allowance for Loan Losses - Accretable Yield for PCI Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance at beginning of period	$ 511	$ 0
Acquisition	58	556
Accretion	(34)	(30)
Net change in expected cash flows	(117)	(15)
Balance at end of period	$ 418	$ 511

Loans Receivable and Allowanc_8

Loans Receivable and Allowance for Loan Losses - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for loan losses:
Total	$ 74,676	$ 61,709	$ 62,342	$ 58,178
Total loans:
Total	6,168,892	6,176,329
Real estate loans | One-to-four family
Allowance for loan losses:
Total	13,586	13,780	15,232	19,991
Total loans:
Total	1,940,636	2,077,508
Real estate loans | Multifamily and commercial
Allowance for loan losses:
Total	30,681	22,980	23,251	19,933
Total loans:
Total	2,822,858	2,924,851
Real estate loans | Construction
Allowance for loan losses:
Total	11,271	7,435	7,217	5,217
Total loans:
Total	328,711	298,942
Commercial business loans
Allowance for loan losses:
Total	17,384	15,836	14,176	8,275
Total loans:
Total	754,013	484,941
Consumer loans | Home equity loans and advances
Allowance for loan losses:
Total	1,748	1,669	2,458	4,576
Total loans:
Total	321,177	388,127
Consumer loans | Other consumer loans
Allowance for loan losses:
Total	6	9	$ 8	$ 8
Total loans:
Total	1,497	1,960
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Allowance for loan losses:
Individually evaluated for impairment	1,088	1,621
Collectively evaluated for impairment	73,588	60,088
Total loans:
Individually evaluated for impairment	45,147	18,811
Collectively evaluated for impairment	6,117,400	6,150,497
Total	6,162,547	6,169,308
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | One-to-four family
Allowance for loan losses:
Individually evaluated for impairment	391	484
Collectively evaluated for impairment	13,195	13,296
Total loans:
Individually evaluated for impairment	7,257	8,891
Collectively evaluated for impairment	1,933,070	2,068,188
Total	1,940,327	2,077,079
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Multifamily and commercial
Allowance for loan losses:
Individually evaluated for impairment	601	2
Collectively evaluated for impairment	30,080	22,978
Total loans:
Individually evaluated for impairment	32,792	2,599
Collectively evaluated for impairment	2,785,173	2,917,386
Total	2,817,965	2,919,985
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Construction
Allowance for loan losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	11,271	7,435
Total loans:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	328,711	298,942
Total	328,711	298,942
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Commercial business loans
Allowance for loan losses:
Individually evaluated for impairment	84	1,121
Collectively evaluated for impairment	17,300	14,715
Total loans:
Individually evaluated for impairment	3,447	5,178
Collectively evaluated for impairment	749,423	478,037
Total	752,870	483,215
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Home equity loans and advances
Allowance for loan losses:
Individually evaluated for impairment	12	14
Collectively evaluated for impairment	1,736	1,655
Total loans:
Individually evaluated for impairment	1,651	2,143
Collectively evaluated for impairment	319,526	385,984
Total	321,177	388,127
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Other consumer loans
Allowance for loan losses:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	6	9
Total loans:
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	1,497	1,960
Total	1,497	1,960
Financial Asset Acquired with Credit Deterioration
Allowance for loan losses:
Total	0	0
Total loans:
Total	6,345	7,021
Financial Asset Acquired with Credit Deterioration | Real estate loans | One-to-four family
Allowance for loan losses:
Total	0	0
Total loans:
Total	309	429
Financial Asset Acquired with Credit Deterioration | Real estate loans | Multifamily and commercial
Allowance for loan losses:
Total	0	0
Total loans:
Total	4,893	4,866
Financial Asset Acquired with Credit Deterioration | Real estate loans | Construction
Allowance for loan losses:
Total	0	0
Total loans:
Total	0	0
Financial Asset Acquired with Credit Deterioration | Commercial business loans
Allowance for loan losses:
Total	0	0
Total loans:
Total	1,143	1,726
Financial Asset Acquired with Credit Deterioration | Consumer loans | Home equity loans and advances
Allowance for loan losses:
Total	0	0
Total loans:
Total	0	0
Financial Asset Acquired with Credit Deterioration | Consumer loans | Other consumer loans
Allowance for loan losses:
Total	0	0
Total loans:
Total	$ 0	$ 0

Loans Receivable and Allowanc_9

Loans Receivable and Allowance for Loan Losses - Troubled Debt Restructuring (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)loan	Dec. 31, 2019USD ($)loan	Dec. 31, 2018USD ($)loan
Financing Receivable, Troubled Debt Restructuring [Line Items]
No. of Loans | loan	7	1	7
Pre-modification Recorded Investment	$ 28,529	$ 4,095	$ 1,454
Post-modification Recorded Investment	$ 29,824	$ 4,095	$ 1,454
Real estate loans | One-to-four family
Financing Receivable, Troubled Debt Restructuring [Line Items]
No. of Loans | loan			5
Pre-modification Recorded Investment			$ 801
Post-modification Recorded Investment			$ 801
Real estate loans | Multifamily and commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
No. of Loans | loan	5	0	1
Pre-modification Recorded Investment	$ 17,022	$ 0	$ 65
Post-modification Recorded Investment	$ 17,022	$ 0	$ 65
Commercial business loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
No. of Loans | loan	2	1
Pre-modification Recorded Investment	$ 11,507	$ 4,095
Post-modification Recorded Investment	$ 12,802	$ 4,095
Consumer loans | Home equity loans and advances
Financing Receivable, Troubled Debt Restructuring [Line Items]
No. of Loans | loan			1
Pre-modification Recorded Investment			$ 588
Post-modification Recorded Investment			$ 588

Loans Receivable and Allowan_10

Loans Receivable and Allowance for Loan Losses - Rollforward of Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Allowance for loan losses:
Beginning balance				$ 61,709				$ 62,342				$ 58,178	$ 61,709	$ 62,342	$ 58,178
Provision charged	$ 627	$ 2,516	$ 5,736	9,568	$ 2,519	$ 1,157	$ 112	436	$ 777	$ 1,500	$ 2,400	2,000	18,447	4,224	6,677
Recoveries													823	496	707
Charge-offs													(6,303)	(5,353)	(3,220)
Ending balance	74,676				61,709				62,342				74,676	61,709	62,342
Real estate loans | One-to-four family
Allowance for loan losses:
Beginning balance				13,780				15,232				19,991	13,780	15,232	19,991
Provision charged													1,299	(429)	(4,503)
Recoveries													438	30	334
Charge-offs													(1,931)	(1,053)	(590)
Ending balance	13,586				13,780				15,232				13,586	13,780	15,232
Real estate loans | Multifamily and commercial
Allowance for loan losses:
Beginning balance				22,980				23,251				19,933	22,980	23,251	19,933
Provision charged													7,713	(178)	3,445
Recoveries													16	10	2
Charge-offs													(28)	(103)	(129)
Ending balance	30,681				22,980				23,251				30,681	22,980	23,251
Real estate loans | Construction
Allowance for loan losses:
Beginning balance				7,435				7,217				5,217	7,435	7,217	5,217
Provision charged													3,835	216	1,997
Recoveries													1	2	3
Charge-offs													0	0	0
Ending balance	11,271				7,435				7,217				11,271	7,435	7,217
Commercial business loans
Allowance for loan losses:
Beginning balance				15,836				14,176				8,275	15,836	14,176	8,275
Provision charged													5,360	5,250	7,860
Recoveries													308	404	240
Charge-offs													(4,120)	(3,994)	(2,199)
Ending balance	17,384				15,836				14,176				17,384	15,836	14,176
Consumer loans | Home equity loans and advances
Allowance for loan losses:
Beginning balance				1,669				2,458				4,576	1,669	2,458	4,576
Provision charged													239	(638)	(1,949)
Recoveries													60	50	122
Charge-offs													(220)	(201)	(291)
Ending balance	1,748				1,669				2,458				1,748	1,669	2,458
Consumer loans | Other consumer loans
Allowance for loan losses:
Beginning balance				$ 9				8				8	9	8	8
Provision charged													1	3	5
Recoveries													0	0	6
Charge-offs													(4)	(2)	(11)
Ending balance	$ 6				$ 9				8				$ 6	9	8
Unallocated
Allowance for loan losses:
Beginning balance								$ 0				$ 178		$ 0	178
Provision charged															(178)
Recoveries															0
Charge-offs															0
Ending balance									$ 0						$ 0

Loans Receivable and Allowan_11

Loans Receivable and Allowance for Loan Losses - Loans Individually Evaluated for Impairment (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Recorded Investment
With no allowance recorded	$ 19,061	$ 10,747
With a specific allowance recorded	26,086	8,064
Recorded investment	45,147	18,811
Unpaid Principal Balance
With no allowance recorded	19,788	12,929
With a specific allowance recorded	26,708	11,088
Unpaid principal balance	46,496	24,017
Specific Allowance
Specific allowance	1,088	1,621
Real estate loans | One-to-four family
Recorded Investment
With no allowance recorded	3,344	4,314
With a specific allowance recorded	3,913	4,577
Recorded investment	7,257	8,891
Unpaid Principal Balance
With no allowance recorded	3,898	5,473
With a specific allowance recorded	3,919	4,613
Unpaid principal balance	7,817	10,086
Specific Allowance
Specific allowance	391	484
Real estate loans | Multifamily and commercial
Recorded Investment
With no allowance recorded	13,058	1,494
With a specific allowance recorded	19,734	1,105
Recorded investment	32,792	2,599
Unpaid Principal Balance
With no allowance recorded	13,094	2,191
With a specific allowance recorded	20,350	1,105
Unpaid principal balance	33,444	3,296
Specific Allowance
Specific allowance	601	2
Commercial business loans
Recorded Investment
With no allowance recorded	1,945	3,859
With a specific allowance recorded	1,502	1,319
Recorded investment	3,447	5,178
Unpaid Principal Balance
With no allowance recorded	1,945	4,048
With a specific allowance recorded	1,502	4,307
Unpaid principal balance	3,447	8,355
Specific Allowance
Specific allowance	84	1,121
Consumer loans | Home equity loans and advances
Recorded Investment
With no allowance recorded	714	1,080
With a specific allowance recorded	937	1,063
Recorded investment	1,651	2,143
Unpaid Principal Balance
With no allowance recorded	851	1,217
With a specific allowance recorded	937	1,063
Unpaid principal balance	1,788	2,280
Specific Allowance
Specific allowance	$ 12	$ 14

Loans Receivable and Allowan_12

Loans Receivable and Allowance for Loan Losses - Interest Income on Impaired Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Recorded Investment
Average Recorded Investment	$ 38,519	$ 21,240	$ 19,357
Interest Income Recognized	1,712	1,203	891
Real estate loans | One-to-four family
Recorded Investment
Average Recorded Investment	7,946	8,811	10,224
Interest Income Recognized	305	434	445
Real estate loans | Multifamily and commercial
Recorded Investment
Average Recorded Investment	23,701	2,639	2,712
Interest Income Recognized	1,091	147	155
Real estate loans | Construction
Recorded Investment
Average Recorded Investment	0	850	0
Interest Income Recognized	0	0	0
Commercial business loans
Recorded Investment
Average Recorded Investment	4,963	6,378	3,060
Interest Income Recognized	216	479	118
Consumer loans | Home equity loans and advances
Recorded Investment
Average Recorded Investment	1,909	2,562	3,361
Interest Income Recognized	$ 100	$ 143	$ 173

Loans Receivable and Allowan_13

Loans Receivable and Allowance for Loan Losses - Credit Quality Indicators (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	$ 6,168,892	$ 6,176,329
Real estate loans | One-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	1,940,636	2,077,508
Real estate loans | Multifamily and commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	2,822,858	2,924,851
Real estate loans | Construction
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	328,711	298,942
Commercial business loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	754,013	484,941
Consumer loans | Home equity loans and advances
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	321,177	388,127
Consumer loans | Other consumer loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	1,497	1,960
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	6,162,547	6,169,308
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	6,084,247	6,115,500
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	47,514	25,313
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	30,786	28,495
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	0	0
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | One-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	1,940,327	2,077,079
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | One-to-four family | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	1,935,032	2,072,878
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | One-to-four family | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	404	419
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | One-to-four family | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	4,891	3,782
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | One-to-four family | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	0	0
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Multifamily and commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	2,817,965	2,919,985
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Multifamily and commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	2,758,905	2,900,286
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Multifamily and commercial | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	40,392	4,724
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Multifamily and commercial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	18,668	14,975
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Multifamily and commercial | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	0	0
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Construction
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	328,711	298,942
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Construction | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	328,711	298,942
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Construction | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	0	0
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Construction | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	0	0
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Real estate loans | Construction | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	0	0
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Commercial business loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	752,870	483,215
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Commercial business loans | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	740,010	454,183
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Commercial business loans | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	6,718	20,170
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Commercial business loans | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	6,142	8,862
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Commercial business loans | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	0	0
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Home equity loans and advances
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	321,177	388,127
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Home equity loans and advances | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	320,092	387,251
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Home equity loans and advances | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	0	0
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Home equity loans and advances | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	1,085	876
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Home equity loans and advances | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	0	0
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Other consumer loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	1,497	1,960
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Other consumer loans | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	1,497	1,960
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Other consumer loans | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	0	0
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Other consumer loans | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	0	0
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration | Consumer loans | Other consumer loans | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total gross loans	$ 0	$ 0

Office Properties and Equipme_3

Office Properties and Equipment, net - Schedule of Office Properties and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Office property and equipment, gross	$ 133,141	$ 130,795
Less accumulated depreciation and amortization	57,167	57,828
Total office properties and equipment, net	75,974	72,967
Land
Property, Plant and Equipment [Line Items]
Office property and equipment, gross	10,174	11,069
Buildings
Property, Plant and Equipment [Line Items]
Office property and equipment, gross	31,523	27,340
Land and building improvements
Property, Plant and Equipment [Line Items]
Office property and equipment, gross	35,307	31,520
Leasehold improvements
Property, Plant and Equipment [Line Items]
Office property and equipment, gross	22,166	24,038
Furniture and equipment
Property, Plant and Equipment [Line Items]
Office property and equipment, gross	$ 33,971	$ 36,828

Office Properties and Equipme_4

Office Properties and Equipment, net - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Depreciation and amortization	$ 6.5	$ 4.9	$ 3.8
Land and building improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, additions	$ 2.6	$ 1.3

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
Total lease liability	$ 20,072
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssets
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilities
Operating lease, weighted average remaining lease term	7 years 6 months
Operating lease, weighted average discount rate	2.26%
Lease, cost	$ 2,400
Operating lease commitments due, next twelve months		$ 4,900
Operating lease commitments due, 2021		4,500
Operating lease commitments due, 2022		4,000
Operating lease commitments due, 2023		3,500
Operating lease commitments due, 2024		2,700
Operating lease commitments due thereafter		$ 5,000
Minimum
Lessee, Lease, Description [Line Items]
Lessee, operating lease, renewal term	3 years
Maximum
Lessee, Lease, Description [Line Items]
Lessee, operating lease, renewal term	10 years
Accounting Standards Update 2016-02
Lessee, Lease, Description [Line Items]
Operating lease, right-of-use asset			$ 22,200
Total lease liability			$ 23,300

Leases - Operating Lease Paymen

Leases - Operating Lease Payment Obligations (Details) $ in Thousands	Dec. 31, 2020USD ($)
Leases [Abstract]
2021	$ 4,010
2022	3,624
2023	3,310
2024	2,586
2025	1,914
Thereafter	6,620
Total undiscounted cash flows	22,064
Discount on cash flows	(1,992)
Total lease liability	$ 20,072

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Schedule of Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 80,285	$ 60,763
Finite-lived intangible assets	6,197
Goodwill and intangible assets	87,384	68,582
Core Deposits
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets	6,197	7,245
Mortgage Servicing Rights
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets	$ 902	$ 574

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 1,048,000	$ 222,000	$ 0
Mortgage Servicing Rights
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	128,000	109,000	73,000
Core Deposits
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 1,000,000	$ 222,000	$ 0

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Schedule of Amortization of Core Deposit Intangibles (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Acquired Finite-Lived Intangible Assets [Line Items]
Total	$ 6,197
Core Deposits
Acquired Finite-Lived Intangible Assets [Line Items]
2021	1,024
2022	961
2023	892
2024	819
2025	737
Thereafter	1,764
Total	$ 6,197	$ 7,245

Deposits - Schedule of Deposits

Deposits - Schedule of Deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Balance
Non-interest-bearing demand	$ 1,354,605	$ 958,442
Interest-bearing demand	2,189,164	1,720,383
Money market accounts	588,180	410,392
Savings and club deposits	688,309	543,480
Certificates of deposit	1,958,366	2,013,145
Total deposits	$ 6,778,624	$ 5,645,842
Weighted Average Rate
Interest-bearing demand	0.40%	1.03%
Money market accounts	0.36%	0.91%
Savings and club deposits	0.16%	0.15%
Certificates of deposit	1.44%	2.25%
Total deposits	0.59%	1.20%

Deposits - Narrative (Details)

Deposits - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Time Deposits [Line Items]
Interest-bearing demand	$ 2,189,164	$ 1,720,383
Aggregate amount of certificates of deposit exceeding threshold amount	1,000,000	1,100,000
Stewardship Financial Corporation
Time Deposits [Line Items]
Interest-bearing demand	$ 26,300	$ 31,600

Deposits - Schedule of Deposit

Deposits - Schedule of Deposit Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deposits [Abstract]
One year or less	$ 1,494,129	$ 1,293,613
After one year to two years	337,579	548,995
After two years to three years	52,809	142,458
After three years to four years	23,018	11,362
After four years	50,831	16,717
Total term certificate accounts	$ 1,958,366	$ 2,013,145

Deposits - Interest Expense on

Deposits - Interest Expense on Deposits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Assets Sold under Agreements to Repurchase [Line Items]
Interest expense on deposits	$ 55,246	$ 61,551	$ 39,523
Demand (including money market accounts)
Assets Sold under Agreements to Repurchase [Line Items]
Interest expense on deposits	15,556	19,922	12,933
Savings and club deposits
Assets Sold under Agreements to Repurchase [Line Items]
Interest expense on deposits	1,023	770	993
Certificates of deposit
Assets Sold under Agreements to Repurchase [Line Items]
Interest expense on deposits	$ 38,667	$ 40,859	$ 25,597

Borrowings - Schedule of borrow

Borrowings - Schedule of borrowed funds (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Balance	$ 799,364,000	$ 1,407,022,000
Weighted Average Interest Rate	1.20%	2.14%
Overnight lines of credit
Debt Instrument [Line Items]
Balance	$ 0	$ 107,800,000
Weighted Average Interest Rate	0.00%	1.81%
FHLB advances
Debt Instrument [Line Items]
Balance	$ 792,412,000	$ 1,275,391,000
Weighted Average Interest Rate	1.18%	2.09%
Subordinated notes
Debt Instrument [Line Items]
Balance	$ 0	$ 16,899,000
Weighted Average Interest Rate	0.00%	6.75%
Junior subordinated debt
Debt Instrument [Line Items]
Balance	$ 6,952,000	$ 6,932,000
Weighted Average Interest Rate	3.20%	5.09%

Borrowings - Narrative (Details

Borrowings - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Balance	$ 799,364,000	$ 1,407,022,000
Unused line of credit	250,000,000	250,000,000
Advances from federal home loan banks	2,100,000,000	1,900,000,000
Line of Credit
Debt Instrument [Line Items]
Balance	0	107,800,000
Interest expense, debt	425,000	1,800,000	$ 2,200,000
FHLB advances
Debt Instrument [Line Items]
Balance	792,412,000	1,275,391,000
Interest expense, debt	17,700,000	25,200,000	17,100,000
Junior subordinated debt
Debt Instrument [Line Items]
Balance	6,952,000	6,932,000
Interest expense, debt	$ 295,000	$ 65,000	3,500,000
Interest rate, effective percentage	3.20%	5.09%
Subordinated notes
Debt Instrument [Line Items]
Balance	$ 0	$ 16,899,000
Interest expense, debt	448,000	113,000	$ 0
Securities sold under agreements to repurchase
Debt Instrument [Line Items]
Advances from federal home loan banks	222,400,000	246,200,000
Interest rate swaps | FHLB advances
Debt Instrument [Line Items]
Notional amount of derivative	$ 430,000,000	$ 410,000,000
London Interbank Offered Rate (LIBOR) | Junior subordinated debt
Debt Instrument [Line Items]
Basis spread on variable rate	3.20%

Borrowings - Schedule of contra

Borrowings - Schedule of contractual maturity of borrowings (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Total FHLB advances	$ 799,364	$ 1,407,022
Line of Credit and FHLB Advances
Debt Instrument [Line Items]
One year or less	496,042
After one year to two years	179,706
After two years to three years	40,391
After three years to four years	51,273
After four years	25,000
Total FHLB advances	$ 792,412

Stockholders' Equity - Actual C

Stockholders' Equity - Actual Capital Amounts and Ratios (Details) $ in Thousands	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Parent Company
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital conservation buffer, ratio	2.50%
Actual, Amount
Total capital	$ 1,070,361	$ 1,061,555
Tier one capital	998,172	988,172
Common equity tier one capital	990,955	980,995
Tier one leverage capital	$ 998,172	$ 988,172
Ratio, Actual
Capital to risk weighted assets	0.1854	0.1725
Tier one risk based capital to risk weighted assets	0.1729	0.1605
Common equity tier one capital	0.1717	0.1594
Tier one leverage capital to average assets	0.1138	0.1292
Minimum Capital Adequacy Requirements, Amount
Capital required for capital adequacy	$ 461,766	$ 492,438
Tier one risk based capital required for capital adequacy	346,325	369,328
Common equity tier one capital required for capital adequacy	259,744	276,996
Tier one leverage capital required for capital adequacy	$ 350,923	$ 305,824
Minimum Capital Adequacy Requirements, Ratio
Capital required for capital adequacy to risk weighted assets	0.0800	0.0800
Tier one risk based capital required for capital adequacy to risk weighted assets	0.0600	0.0600
Common equity tier one capital required for capital adequacy to risk weighted assets	0.045	0.0450
Tier one leverage capital required for capital adequacy to average assets	0.040	0.0400
Minimum Capital Adequacy Requirements With Capital Conservation Buffer, Amount
Capital required for capital adequacy with capital buffer	$ 606,068	$ 646,324
Tier one risk based capital required for capital adequacy with capital buffer	490,627	523,215
Common equity tier one risk based capital required for capital adequacy with capital buffer	404,046	430,883
Tier one leverage capital required for capital adequacy with capital buffer to average assets	$ 350,923	$ 305,824
Minimum Capital Adequacy Requirements With Capital Conservation Buffer, Ratio
Capital required for capital adequacy with capital buffer to risk weighted assets	0.1050	0.1050
Tier one risk based capital required for capital adequacy with capital buffer to risk weighted assets	0.0850	0.0850
Common equity tier one risk based capital requirement for capital adequacy with capital buffer to risk weighted assets	0.0700	0.0700
Tier one leverage capital requirement for capital adequacy with capital buffer to average assets	4.00%	4.00%
Subsidiaries
Actual, Amount
Total capital	$ 924,959	$ 844,664
Tier one capital	852,897	782,881
Common equity tier one capital	852,897	782,881
Tier one leverage capital	$ 852,897	$ 782,881
Ratio, Actual
Capital to risk weighted assets	0.1605	0.1425
Tier one risk based capital to risk weighted assets	0.1480	0.1321
Common equity tier one capital	0.1480	0.1321
Tier one leverage capital to average assets	0.0972	0.1025
Minimum Capital Adequacy Requirements, Amount
Capital required for capital adequacy	$ 460,944	$ 474,125
Tier one risk based capital required for capital adequacy	345,708	355,594
Common equity tier one capital required for capital adequacy	259,281	266,696
Tier one leverage capital required for capital adequacy	$ 350,815	$ 305,423
Minimum Capital Adequacy Requirements, Ratio
Capital required for capital adequacy to risk weighted assets	0.0800	0.0800
Tier one risk based capital required for capital adequacy to risk weighted assets	0.0600	0.0600
Common equity tier one capital required for capital adequacy to risk weighted assets	0.0450	0.0450
Tier one leverage capital required for capital adequacy to average assets	0.0400	0.0400
Minimum Capital Adequacy Requirements With Capital Conservation Buffer, Amount
Capital required for capital adequacy with capital buffer	$ 604,989	$ 622,290
Tier one risk based capital required for capital adequacy with capital buffer	489,753	503,758
Common equity tier one risk based capital required for capital adequacy with capital buffer	403,326	414,860
Tier one leverage capital required for capital adequacy with capital buffer to average assets	$ 350,815	$ 305,423
Minimum Capital Adequacy Requirements With Capital Conservation Buffer, Ratio
Capital required for capital adequacy with capital buffer to risk weighted assets	0.1050	0.1050
Tier one risk based capital required for capital adequacy with capital buffer to risk weighted assets	0.0850	0.0850
Common equity tier one risk based capital requirement for capital adequacy with capital buffer to risk weighted assets	0.0700	0.0700
Tier one leverage capital requirement for capital adequacy with capital buffer to average assets	4.00%	4.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount
Capital required to be well capitalized, amount	$ 576,180	$ 592,657
Tier one risk based capital required to be well capitalized, amount	460,944	474,125
Common equity tier one capital required to be well-capitalized, amount	374,517	385,227
Tier one leverage capital required to be well capitalized, amount	$ 438,519	$ 381,779
To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio
Capital required to be well capitalized to risk weighted assets, ratio	0.1000	0.1000
Tier one risk based capital required to be well capitalized to risk weighted assets, ratio	0.0800	0.0800
Common equity tier one capital required to be well-capitalized to risk weighted assets, ratio	0.0650	0.0650
Tier one leverage capital required to be well capitalized to average assets, ratio	0.0500	0.0500

Stockholders' Equity - Narrativ

Stockholders' Equity - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	Sep. 10, 2020	Dec. 05, 2019	Jun. 13, 2019	Dec. 31, 2020	Dec. 31, 2019
Equity [Abstract]
Number of shares authorized to be repurchased (in shares)	5,000,000		4,000,000
Stock repurchase program, percent of common stock	4.30%		3.50%
Additional shares acquired in stock repurchase program (in shares)		3,000,000
Treasury stock, shares purchased (in shares)				7,587,142	3,543,800
Cost method of shares repurchase				$ 108,166	$ 55,309
Cost method of shares repurchased (in dollars per share)				$ 14.26	$ 15.61

Employee Benefit Plans - Schedu

Employee Benefit Plans - Schedule of Change in Benefit Obligation and Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Plan
Change in benefit obligation:
Benefit obligation, beginning balance	$ 263,826	$ 209,205
Acquired	0	0
Service cost	7,985	6,494	$ 7,805
Interest cost	7,608	8,569	8,489
Actuarial (gain) loss	40,281	46,001
Benefits paid	(7,260)	(6,443)
Benefit obligation, ending balance	312,440	263,826	209,205
Change in plan assets:
Fair value of plan assets, beginning balance	356,347	272,974
Actuarial return on plan assets	50,820	54,816
Employer contributions	12,000	35,000
Benefits paid	(7,260)	(6,443)
Fair value of plan assets, ending balance	411,907	356,347	272,974
Funded status at end of year	99,467	92,521
RIM Plan
Change in benefit obligation:
Benefit obligation, beginning balance	13,696	11,285
Acquired	0	0
Service cost	267	210	282
Interest cost	405	466	443
Actuarial (gain) loss	2,506	2,074
Benefits paid	(344)	(339)
Benefit obligation, ending balance	16,530	13,696	11,285
Change in plan assets:
Fair value of plan assets, beginning balance	0	0
Actuarial return on plan assets	0	0
Employer contributions	344	339
Benefits paid	(344)	(339)
Fair value of plan assets, ending balance	0	0	0
Funded status at end of year	(16,530)	(13,696)
Post-retirement Plan
Change in benefit obligation:
Benefit obligation, beginning balance	24,603	20,964
Acquired	0	0
Service cost	394	339	417
Interest cost	683	826	796
Actuarial (gain) loss	5,506	3,141
Benefits paid	(565)	(667)
Benefit obligation, ending balance	30,621	24,603	20,964
Change in plan assets:
Fair value of plan assets, beginning balance	0	0
Actuarial return on plan assets	0	0
Employer contributions	565	667
Benefits paid	(565)	(667)
Fair value of plan assets, ending balance	0	0	0
Funded status at end of year	(30,621)	(24,603)
Split-Dollar Life Insurance
Change in benefit obligation:
Benefit obligation, beginning balance	14,100	10,462
Acquired	1,981	310
Service cost	467	354	374
Interest cost	507	457	428
Actuarial (gain) loss	3,137	2,649
Benefits paid	(211)	(132)
Benefit obligation, ending balance	19,981	14,100	10,462
Change in plan assets:
Fair value of plan assets, beginning balance	0	0
Actuarial return on plan assets	0	0
Employer contributions	211	132
Benefits paid	(211)	(132)
Fair value of plan assets, ending balance	0	0	$ 0
Funded status at end of year	$ (19,981)	$ (14,100)

Employee Benefit Plans - Narrat

Employee Benefit Plans - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
	Apr. 30, 2018	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Bank-owned life insurance			$ 232,824	$ 211,415
Bank-owned life insurance income		$ 5,200	6,620	5,846	$ 5,208
Employee stock ownership plan, compensation expense			$ 3,161	$ 3,566	$ 2,594
Exercises in period (in shares)			0	0	0
RIM Plan
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, funded (unfunded) status of plan			$ (16,530)	$ (13,696)
Defined contribution plan, cost			4	11	$ 9
Employee stock ownership plan, compensation expense			215	267	165
Defined benefit plan, net periodic benefit cost (credit)			1,069	920	1,138
RIM Plan | Roselle Entities
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, net periodic benefit cost (credit)			11
Post-retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, funded (unfunded) status of plan			(30,621)	(24,603)
Defined benefit plan, net periodic benefit cost (credit)			1,386	1,312	1,430
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, funded (unfunded) status of plan			99,467	92,521
Defined contribution plan, cost			1,700	1,400	1,300
Defined benefit plan, net periodic benefit cost (credit)			$ (2,880)	(2,925)	(1,383)
Maximum
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent of match			4.50%
Maximum | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent of match			4.50%
Minimum
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent of match			3.00%
Minimum | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent of match			3.00%
Columbia Bank Employee Stock Ownership Plan
Defined Benefit Plan Disclosure [Line Items]
Proceeds from repayments of loans by employee stock ownership plans	$ 45,400
Loan term	20 years		20 years
Shares contributed to ESOP (in shares)	4,542,855
Fixed interest rate	4.75%
Employee stock ownership plan, compensation expense			$ 3,200	$ 3,600	$ 2,600

Employee Benefit Plans - Sche_2

Employee Benefit Plans - Schedule of Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Unrecognized prior service costs	$ 0	$ 0	$ 0
Unrecognized net actuarial income	76,686	68,752	59,579
Total accumulated other comprehensive income	76,686	68,752	59,579
RIM Plan
Defined Benefit Plan Disclosure [Line Items]
Unrecognized prior service costs	0	0	0
Unrecognized net actuarial income	7,686	5,777	3,748
Total accumulated other comprehensive income	7,686	5,777	3,748
Post-retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Unrecognized prior service costs	0	0	0
Unrecognized net actuarial income	12,417	7,221	4,226
Total accumulated other comprehensive income	12,417	7,221	4,226
Split-Dollar Life Insurance
Defined Benefit Plan Disclosure [Line Items]
Unrecognized prior service costs	405	461	517
Unrecognized net actuarial income	8,741	6,058	3,658
Total accumulated other comprehensive income	$ 9,146	$ 6,519	$ 4,175

Employee Benefit Plans - Sche_3

Employee Benefit Plans - Schedule of Net Periodic Benefit Cost (Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 7,985	$ 6,494	$ 7,805
Interest cost	7,608	8,569	8,489
Expected return on plan assets	(23,375)	(21,058)	(20,794)
Amortization of Prior service cost	0	0	0
Amortization of Net loss	4,902	3,070	3,117
Net periodic (income) benefit cost	(2,880)	(2,925)	(1,383)
RIM Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	267	210	282
Interest cost	405	466	443
Expected return on plan assets	0	0	0
Amortization of Prior service cost	0	0	0
Amortization of Net loss	397	244	413
Net periodic (income) benefit cost	1,069	920	1,138
Post-retirement Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	394	339	417
Interest cost	683	826	796
Expected return on plan assets	0	0	0
Amortization of Prior service cost	0	0	(106)
Amortization of Net loss	309	147	323
Net periodic (income) benefit cost	1,386	1,312	1,430
Split-Dollar Life Insurance
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	467	354	374
Interest cost	507	457	428
Expected return on plan assets	0	0	0
Amortization of Prior service cost	56	56	32
Amortization of Net loss	454	247	506
Net periodic (income) benefit cost	$ 1,484	$ 1,114	$ 1,340

Employee Benefit Plans - Retros

Employee Benefit Plans - Retrospective Application of the Statement of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Compensation and employee benefits	$ 100,687	$ 84,256	$ 77,226
Other non-interest expense	$ 21,499	$ 11,769	5,597
Accounting Standards Update 2017-07
Defined Benefit Plan Disclosure [Line Items]
Compensation and employee benefits			77,226
Other non-interest expense			5,597
Accounting Standards Update 2017-07 | Previously Reported
Defined Benefit Plan Disclosure [Line Items]
Compensation and employee benefits			69,907
Other non-interest expense			$ 12,916

Employee Benefit Plans - Sche_4

Employee Benefit Plans - Schedule of Weighted Average Actuarial Assumptions (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.92%	3.49%	4.57%
Rate of compensation increase	3.75%	3.50%	3.50%
Benefit obligation	3.49%	4.57%	3.75%
Remeasurement rate	2.74%	3.85%
Service cost	3.66%	4.70%
Remeasurement rate	2.97%	4.04%
Interest cost	3.12%	4.25%
Remeasurement rate	2.22%	3.44%
Expected rate of return on plan assets	6.50%	7.00%	7.25%
Rate of compensation increase	3.50%	3.50%	3.50%
RIM Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.67%	3.33%	4.47%
Rate of compensation increase	3.75%	3.50%	3.50%
Benefit obligation	3.33%	4.47%	4.47%
Service cost	3.46%	4.57%	4.57%
Interest cost	3.00%	4.18%	4.18%
Rate of compensation increase	3.50%	3.50%	3.50%
Post-retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.59%	3.27%	4.41%
Benefit obligation	3.27%	4.41%	3.625%
Service cost	3.52%	4.60%
Interest cost	2.85%	4.05%
Split-Dollar Life Insurance
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.01%	3.54%	4.63%
Rate of compensation increase	3.75%	3.50%	3.50%
Benefit obligation	3.54%	4.63%	3.75%
Service cost	3.71%	4.74%
Interest cost	3.28%	4.39%
Rate of compensation increase	3.50%	3.50%	3.50%

Employee Benefit Plans - Sche_5

Employee Benefit Plans - Schedule of Assumed Health Care Cost Trend Rates (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Retirement Benefits [Abstract]
Effect on total service cost and interest cost, increase	$ 19
Effect on post-retirement benefit obligations, increase	175
Effect on total service cost and interest cost, decrease	(16)
Effect on post-retirement benefit obligations, decrease	$ (154)

Employee Benefit Plans - Sche_6

Employee Benefit Plans - Schedule of Estimated Future Benefit Payments (Details) $ in Thousands	Dec. 31, 2020USD ($)
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
2021	$ 8,568
2022	9,141
2023	9,847
2024	10,592
2025	11,388
2026 - 2030	68,978
RIM Plan
Defined Benefit Plan Disclosure [Line Items]
2021	384
2022	436
2023	534
2024	673
2025	778
2026 - 2030	4,415
Post-retirement Plan
Defined Benefit Plan Disclosure [Line Items]
2021	1,490
2022	1,525
2023	1,559
2024	1,622
2025	1,675
2026 - 2030	8,820
Split-Dollar Life Insurance
Defined Benefit Plan Disclosure [Line Items]
2021	270
2022	312
2023	363
2024	412
2025	461
2026 - 2030	$ 3,179

Employee Benefit Plans - Sche_7

Employee Benefit Plans - Schedule of Weighted Average and Target Allocations of Pension Assets (Details) - Pension Plan	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Weighted average assets allocations, percentage	100.00%	100.00%
Domestic equities
Defined Benefit Plan Disclosure [Line Items]
Weighted average assets allocations, percentage	44.10%	39.60%
Foreign equities
Defined Benefit Plan Disclosure [Line Items]
Weighted average assets allocations, percentage	13.40%	9.60%
Fixed income
Defined Benefit Plan Disclosure [Line Items]
Weighted average assets allocations, percentage	37.80%	44.30%
Commingled real estate funds
Defined Benefit Plan Disclosure [Line Items]
Weighted average assets allocations, percentage	4.40%	6.10%
Money market mutual funds
Defined Benefit Plan Disclosure [Line Items]
Weighted average assets allocations, percentage	0.30%	0.40%
Minimum | Equities
Defined Benefit Plan Disclosure [Line Items]
Plan assets, target allocation, percent	40.00%
Minimum | Fixed income
Defined Benefit Plan Disclosure [Line Items]
Plan assets, target allocation, percent	40.00%
Minimum | Commingled real estate funds
Defined Benefit Plan Disclosure [Line Items]
Plan assets, target allocation, percent	0.00%
Minimum | Money market mutual funds
Defined Benefit Plan Disclosure [Line Items]
Plan assets, target allocation, percent	0.00%
Maximum | Equities
Defined Benefit Plan Disclosure [Line Items]
Plan assets, target allocation, percent	60.00%
Maximum | Fixed income
Defined Benefit Plan Disclosure [Line Items]
Plan assets, target allocation, percent	60.00%
Maximum | Commingled real estate funds
Defined Benefit Plan Disclosure [Line Items]
Plan assets, target allocation, percent	10.00%
Maximum | Money market mutual funds
Defined Benefit Plan Disclosure [Line Items]
Plan assets, target allocation, percent	15.00%

Employee Benefit Plans - Sche_8

Employee Benefit Plans - Schedule of Fair Value of Plan Assets (Details) - Pension Plan - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 411,907	$ 356,347	$ 272,974
Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	393,948	334,751
Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	17,959	21,596
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Money market mutual funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,434	1,462
Money market mutual funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,434	1,462
Money market mutual funds | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Money market mutual funds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mutual funds - value stock fund
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	29,914	27,827
Mutual funds - value stock fund | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	29,914	27,827
Mutual funds - value stock fund | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mutual funds - value stock fund | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mutual funds - fixed income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	155,864	158,030
Mutual funds - fixed income | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	155,864	158,030
Mutual funds - fixed income | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mutual funds - fixed income | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mutual funds - international stock
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	55,300	34,332
Mutual funds - international stock | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	55,300	34,332
Mutual funds - international stock | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mutual funds - international stock | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mutual funds - institutional stock index
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	151,436	113,100
Mutual funds - institutional stock index | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	151,436	113,100
Mutual funds - institutional stock index | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Mutual funds - institutional stock index | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Commingled real estate funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	17,959	21,596
Commingled real estate funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Commingled real estate funds | Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	17,959	21,596
Commingled real estate funds | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0	$ 0

Employee Benefit Plans - Sche_9

Employee Benefit Plans - Schedule of Employee Stock Ownership Plan (Details) - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Retirement Benefits [Abstract]
Allocated shares (in shares)	606	385
Unearned shares (in shares)	3,929	4,156
Total ESOP shares (in shares)	4,535	4,541
Fair value of unearned ESOP shares	$ 61,139	$ 70,409

Employee Benefit Plans - Stock

Employee Benefit Plans - Stock Based Compensation Narrative (Details) - USD ($)	Dec. 14, 2020	Dec. 16, 2019	Jul. 23, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jun. 06, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)							7,949,996
Grants in period (in shares)		184,378	3,707,901	10,457	3,892,279
Grants in period (in dollars per share)		$ 4.59	$ 4.25
Grants in period (in dollars per share)		$ 17	$ 15.60	$ 15.98	$ 15.60
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)							2,271,427
Equity instruments other than options, grants in period (in shares)	33,160	74,673	1,389,570	33,160	1,464,243
Equity instruments other than options, grants in period (in dollars per share)	$ 15.08	$ 17	$ 15.60	$ 15.08	$ 15.67
Share-based payment expense				$ 5,600,000	$ 2,300,000	$ 0
Equity instrument other than options, nonvested (in shares)				1,263,169	1,420,012	0
Nonvested award, excluding option, cost not yet recognized				$ 14,600,000
Cost not yet recognized, period for recognition				3 years
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)							5,678,569
Award vesting period (in years)		5 years	5 years
Share-based payment expense				$ 3,200,000	$ 1,400,000	$ 0
Equity instrument other than options, nonvested (in shares)				2,965,330
Nonvested award, excluding option, cost not yet recognized				$ 11,300,000
Cost not yet recognized, period for recognition				3 years 7 months 6 days
Expiration period (in years)		10 years	10 years
Expected term		6 years 6 months	6 years 6 months
Risk free interest rate		1.79%	1.90%
Expected volatility rate		22.23%	22.12%
Expected dividend rate		0.00%	0.00%
Minimum | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)				1 year
Maximum | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)				5 years
Share-based Payment Arrangement, Tranche One | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)				1 year
Share-based Payment Arrangement, Tranche One | Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)		1 year	1 year

Employee Benefit Plans - Restri

Employee Benefit Plans - Restricted Stock Activity (Details) - $ / shares	Dec. 14, 2020	Dec. 16, 2019	Jul. 23, 2019	Dec. 31, 2020	Dec. 31, 2019
Number of Restricted Shares
Vested (in shares)				(172,756)
Weighted Average Grant Date Fair Value
Vested (in dollars per share)				$ 15.66
Restricted Stock
Number of Restricted Shares
Beginning balance (in shares)				1,420,012	0
Granted (in shares)	33,160	74,673	1,389,570	33,160	1,464,243
Forfeited (in shares)				(17,247)	(44,231)
Ending balance (in shares)				1,263,169	1,420,012
Weighted Average Grant Date Fair Value
Beginning balance (in dollars per share)				$ 15.67	$ 0
Granted (in dollars per share)	$ 15.08	$ 17	$ 15.60	15.08	15.67
Forfeited (in dollars per share)				16.02	15.60
Ending balance (in dollars per share)				$ 15.66	$ 15.67

Employee Benefit Plans - Stoc_2

Employee Benefit Plans - Stock Option Activity (Details) - USD ($)	Dec. 16, 2019	Jul. 23, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Number of Stock Options
Beginning balance (in shares)			3,784,044	0
Granted (in shares)	(184,378)	(3,707,901)	(10,457)	(3,892,279)
Forfeited (in shares)			(64,959)	(108,235)
Ending balance (in shares)			3,708,628	3,784,044
Options exercisable (in shares)			743,298
Weighted Average Exercise Price
Beginning balance (in dollars per share)			$ 15.67	$ 0
Granted (in dollars per share)	$ 17	$ 15.60	15.98	15.60
Forfeited (in dollars per share)			15.84
Ending balance (in dollars per share)			15.66	$ 15.67
Options exercisable (in dollars per share)			$ 15.66
Weighted Average Remaining Contractual Term (in years)
Granted				9 years 7 months 6 days
Outstanding			8 years 7 months 6 days	9 years 7 months 6 days
Options exercisable			8 years 6 months
Aggregate Intrinsic Value
Outstanding			$ 0	$ 4,812,490	$ 0

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Contingency [Line Items]
Deferred income tax expense (benefit), related to unrealized gain (losses) on available-for-sale securities	$ (5,600)	$ (5,500)	$ 1,400
Reclassification adjustment of actuarial net (loss) gain included in net income	900	779	(530)
Deferred tax expense (benefit)	9,738	7,527	$ (5,490)
Included in retained earnings, no provision for income tax	21,500	21,500
Valuation allowance	3,411	7,442
Operating loss carryforwards	108,400	99,800
Stewardship Financial Corporation
Income Tax Contingency [Line Items]
Deferred tax expense (benefit)	5,400	2,300
Operating loss carryforwards		$ 5,800
Operating loss carryforwards, net	1,100
Deferred tax assets, operating loss carryforwards, subject to expiration	1,000
Roselle Entities
Income Tax Contingency [Line Items]
Operating loss carryforwards	11,900
New Jersey Division of Taxation
Income Tax Contingency [Line Items]
Tax credit carryforward, amount	$ 2,200

Income Taxes - Schedule of Inco

Income Taxes - Schedule of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
Federal													$ 5,072	$ 5,933	$ 11,284
State													3,844	2,905	5,129
Total current													8,916	8,838	16,413
Deferred:
Federal													9,847	8,275	(4,901)
State													(109)	(748)	(589)
Total deferred													9,738	7,527	(5,490)
Total income tax expense	$ 6,547	$ 5,252	$ 4,603	$ 2,252	$ 3,832	$ 5,392	$ 3,634	$ 3,507	$ 3,123	$ 6,956	$ (2,961)	$ 3,805	$ 18,654	$ 16,365	$ 10,923

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Tax expense at applicable statutory rate													$ 16,013	$ 14,927	$ 7,067
Increase (decrease) in taxes resulting from:
State tax, net of federal income tax benefit													2,951	1,704	3,587
ESOP fair market value adjustment													187	272	202
Tax exempt interest income													(11)	(6)	(4)
Income from Bank-owned life insurance													(1,075)	(1,246)	(812)
Dividend received deduction													(9)	(8)	(16)
Non-deductible merger-related expenses													42	222	0
Non-deductible compensation expense													0	398	0
Other, net													556	102	899
Total income tax expense	$ 6,547	$ 5,252	$ 4,603	$ 2,252	$ 3,832	$ 5,392	$ 3,634	$ 3,507	$ 3,123	$ 6,956	$ (2,961)	$ 3,805	$ 18,654	$ 16,365	$ 10,923

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Allowance for loan losses	$ 20,878	$ 13,114
Post-retirement benefits	5,928	4,089
Deferred compensation	2,779	2,085
Depreciation	0	1,002
Retirement Income Maintenance plan	2,471	1,725
ESOP	624	301
Stock-based compensation	2,724	788
Reserve for uncollected interest	126	54
Net unrealized losses on debt securities and defined benefit plans	18,511	18,374
Federal and State NOLs	9,719	2,063
Alternative minimum assessment carryforwards	2,156	2,156
Charitable contribution carryforward	6,359	5,981
Purchase accounting	1,024	0
Lease liability	5,609
Other items	3,215	332
Gross deferred tax assets	82,123	58,999
Valuation allowance	(3,411)	(7,442)
Total deferred tax assets, net	78,712	51,557
Deferred tax liabilities:
Pension expense	49,225	33,856
Deferred Tax Liabilities, Depreciation	6,118	0
Deferred loan costs	8,555	5,911
Intangible assets	1,597	1,215
Deferred Tax Liabilities, Leasing Arrangements	5,317
Other items	716	266
Total gross deferred tax liabilities	71,528	41,248
Net deferred tax asset	$ 7,184	$ 10,309

Financial Transactions with O_3

Financial Transactions with Off-Balance-Sheet Risk and Concentrations of Credit Risk - Schedule of Loan Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Concentration Risk [Line Items]
Loan commitments	$ 282,198	$ 270,881
Residential real estate
Concentration Risk [Line Items]
Loan commitments	149,847	91,141
Multifamily and commercial
Concentration Risk [Line Items]
Loan commitments	98,910	95,025
Commercial business loans
Concentration Risk [Line Items]
Loan commitments	16,842	18,737
Construction
Concentration Risk [Line Items]
Loan commitments	13,335	59,990
Home equity loans and advances
Concentration Risk [Line Items]
Loan commitments	$ 3,264	$ 5,988

Financial Transactions with O_4

Financial Transactions with Off-Balance-Sheet Risk and Concentrations of Credit Risk - Narrative (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Loss Contingencies [Line Items]
Derivative (liabilities), at fair value, net	$ (23,000,000)	$ (11,400,000)
Unused lines of Credit
Loss Contingencies [Line Items]
Fair value disclosure, off-balance sheet risk, amount, liability	894,500,000	910,000,000
Mortgages
Loss Contingencies [Line Items]
Fair value disclosure, off-balance sheet risk, amount, liability	0
Letter of Credit
Loss Contingencies [Line Items]
Fair value disclosure, off-balance sheet risk, amount, liability	$ 9,400,000	$ 8,400,000

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	$ 1,316,952	$ 1,098,336
Equity securities, at fair value	5,418	2,855
U.S. government and agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	25,549	42,386
Mortgage-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	1,200,394	979,881
Municipal obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	16,862	2,284
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	69,477	69,180
Trust preferred securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	4,670	4,605
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value		42,386
Equity securities, at fair value	5,072	2,587
Derivative assets	0	0
Derivative liabilities	0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value		1,055,950
Equity securities, at fair value	346	268
Derivative assets	19,425	185
Derivative liabilities	42,384	11,546
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	0	0
Equity securities, at fair value		0
Derivative assets	0	0
Derivative liabilities	0	0
Measured on recurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	1,316,952	1,098,336
Equity securities, at fair value	5,418	2,855
Derivative assets	19,425	185
Assets	1,341,795	1,101,376
Derivative liabilities	42,384	11,546
Measured on recurring basis | U.S. government and agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	25,549	42,386
Measured on recurring basis | Mortgage-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	1,200,394	979,881
Measured on recurring basis | Municipal obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	16,862	2,284
Measured on recurring basis | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	69,477	69,180
Measured on recurring basis | Trust preferred securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	4,670	4,605
Measured on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	25,549	42,386
Equity securities, at fair value	5,072	2,587
Derivative assets	0	0
Assets	30,621	44,973
Derivative liabilities	0	0
Measured on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. government and agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	25,549	42,386
Measured on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Mortgage-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	0	0
Measured on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Municipal obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	0	0
Measured on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	0	0
Measured on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Trust preferred securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	0	0
Measured on recurring basis | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	1,291,403	1,055,950
Equity securities, at fair value	346	268
Derivative assets	19,425	185
Assets	1,311,174	1,056,403
Derivative liabilities	42,384	11,546
Measured on recurring basis | Significant Other Observable Inputs (Level 2) | U.S. government and agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	0	0
Measured on recurring basis | Significant Other Observable Inputs (Level 2) | Mortgage-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	1,200,394	979,881
Measured on recurring basis | Significant Other Observable Inputs (Level 2) | Municipal obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	16,862	2,284
Measured on recurring basis | Significant Other Observable Inputs (Level 2) | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	69,477	69,180
Measured on recurring basis | Significant Other Observable Inputs (Level 2) | Trust preferred securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	4,670	4,605
Measured on recurring basis | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	0	0
Equity securities, at fair value	0	0
Derivative assets	0	0
Assets	0	0
Derivative liabilities	0	0
Measured on recurring basis | Significant Unobservable Inputs (Level 3) | U.S. government and agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	0	0
Measured on recurring basis | Significant Unobservable Inputs (Level 3) | Mortgage-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	0	0
Measured on recurring basis | Significant Unobservable Inputs (Level 3) | Municipal obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	0	0
Measured on recurring basis | Significant Unobservable Inputs (Level 3) | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	0	0
Measured on recurring basis | Significant Unobservable Inputs (Level 3) | Trust preferred securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale, at fair value	$ 0	$ 0

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details)	12 Months Ended
	Dec. 31, 2020
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Adjustments for estimated costs to sell collateral dependent impaired loans	6.00%
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Adjustments for estimated costs to sell collateral dependent impaired loans	8.00%

Fair Value Measurements - Ass_2

Fair Value Measurements - Assets and Liabilities Measured on Non-Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, at fair value	$ 0	$ 0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, at fair value	0	0
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, at fair value	6,394,524	6,219,008
Measured on non-recurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, at fair value		1,063
Mortgage servicing rights	1,338	681
Assets	1,338	1,744
Measured on non-recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, at fair value		0
Mortgage servicing rights	0	0
Assets	0	0
Measured on non-recurring basis | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, at fair value		0
Mortgage servicing rights	0	0
Assets	0	0
Measured on non-recurring basis | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-sale, at fair value		1,063
Mortgage servicing rights	1,338	681
Assets	$ 1,338	$ 1,744

Fair Value Measurements - Quali

Fair Value Measurements - Qualitative Valuation (Details) $ in Thousands	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Measured on non-recurring basis
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Loans held-for-sale, at fair value		$ 1,063
Mortgage servicing rights	$ 1,338	681
Significant Unobservable Inputs (Level 3)
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Loans held-for-sale, at fair value	6,394,524	6,219,008
Significant Unobservable Inputs (Level 3) | Measured on non-recurring basis
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Loans held-for-sale, at fair value		1,063
Mortgage servicing rights	$ 1,338	$ 681
Significant Unobservable Inputs (Level 3) | Discount Rate | Measured on non-recurring basis | Estimated Cash Flow
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired financing receivable, measurement input		0
Significant Unobservable Inputs (Level 3) | Discount Rate | Measured on non-recurring basis | Weighted Average | Estimated Cash Flow
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired financing receivable, measurement input		0
Servicing asset, measurement input	0.1025	0.1175
Significant Unobservable Inputs (Level 3) | Prepayments Speeds and Discount Rates | Measured on non-recurring basis | Minimum | Estimated Cash Flow
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing asset, measurement input	0.097	0.036
Significant Unobservable Inputs (Level 3) | Prepayments Speeds and Discount Rates | Measured on non-recurring basis | Maximum | Estimated Cash Flow
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing asset, measurement input	0.262	0.240
Significant Unobservable Inputs (Level 3) | Prepayments Speeds and Discount Rates | Measured on non-recurring basis | Weighted Average | Estimated Cash Flow
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Servicing asset, measurement input	0.167	0.127

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value on Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Financial assets:
Debt securities available for sale, at fair value	$ 1,316,952	$ 1,098,336
Debt securities held to maturity	277,091	289,505
Equity securities, at fair value	5,418	2,855
Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets:
Cash and cash equivalents	422,957	75,547
Debt securities available for sale, at fair value		42,386
Debt securities held to maturity	5,001	19,960
Equity securities, at fair value	5,072	2,587
Federal Home Loan Bank stock	0	0
Loans receivable, net	0	0
Derivative assets	0	0
Financial liabilities:
Deposits	0	0
Borrowings	0	0
Derivative liabilities	0	0
Significant Other Observable Inputs (Level 2)
Financial assets:
Cash and cash equivalents	0	0
Debt securities available for sale, at fair value		1,055,950
Debt securities held to maturity	272,090	269,545
Equity securities, at fair value	346	268
Federal Home Loan Bank stock	43,759	69,579
Loans receivable, net	0	0
Derivative assets	19,425	185
Financial liabilities:
Deposits	6,793,034	5,654,075
Borrowings	808,853	1,411,962
Derivative liabilities	42,384	11,546
Significant Unobservable Inputs (Level 3)
Financial assets:
Cash and cash equivalents	0	0
Debt securities available for sale, at fair value	0	0
Debt securities held to maturity	0	0
Equity securities, at fair value		0
Federal Home Loan Bank stock	0	0
Loans receivable, net	6,394,524	6,219,008
Derivative assets	0	0
Financial liabilities:
Deposits	0	0
Borrowings	0	0
Derivative liabilities	0	0
Carrying Value
Financial assets:
Cash and cash equivalents	422,957	75,547
Debt securities available for sale, at fair value	1,316,952	1,098,336
Debt securities held to maturity	262,720	285,756
Equity securities, at fair value	5,418	2,855
Federal Home Loan Bank stock	43,759	69,579
Loans receivable, net	6,107,094	6,135,857
Derivative assets	19,425	185
Financial liabilities:
Deposits	6,778,624	5,645,842
Borrowings	799,364	1,407,022
Derivative liabilities	42,384	11,546
Total Fair Value
Financial assets:
Cash and cash equivalents	422,957	75,547
Debt securities available for sale, at fair value	1,316,952	1,098,336
Debt securities held to maturity	277,091	289,505
Equity securities, at fair value	5,418	2,855
Federal Home Loan Bank stock	43,759	69,579
Loans receivable, net	6,394,524	6,219,008
Derivative assets	19,425	185
Financial liabilities:
Deposits	6,793,034	5,654,075
Borrowings	808,853	1,411,962
Derivative liabilities	$ 42,384	$ 11,546

Selected Quarterly Financial _3

Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Total interest income	$ 72,501	$ 72,933	$ 75,587	$ 74,690	$ 71,026	$ 64,438	$ 62,732	$ 62,887	$ 61,785	$ 57,695	$ 55,019	$ 51,791	$ 295,711	$ 261,083	$ 226,290
Total interest expense	13,825	16,609	19,716	23,988	23,598	22,722	21,889	20,503	18,410	17,112	14,004	12,730	74,138	88,712	62,256
Net interest income	58,676	56,324	55,871	50,702	47,428	41,716	40,843	42,384	43,375	40,583	41,015	39,061	221,573	172,371	164,034
Provision charged	627	2,516	5,736	9,568	2,519	1,157	112	436	777	1,500	2,400	2,000	18,447	4,224	6,677
Net interest income after provision for credit losses	58,049	53,808	50,135	41,134	44,909	40,559	40,731	41,948	42,598	39,083	38,615	37,061	203,126	168,147	157,357
Total non-interest income	9,962	7,909	7,008	6,391	8,709	10,115	6,775	6,037	6,405	5,290	5,450	4,543	31,270	31,636	21,688
Total non-interest expense	40,810	41,378	37,443	38,508	36,237	31,064	31,841	29,559	31,013	26,590	61,768	26,015	158,139	128,701	145,386
Income before income tax expense	27,201	20,339	19,700	9,017	17,381	19,610	15,665	18,426	17,990	17,783	(17,703)	15,589	76,257	71,082	33,659
Income tax expense	6,547	5,252	4,603	2,252	3,832	5,392	3,634	3,507	3,123	6,956	(2,961)	3,805	18,654	16,365	10,923
Net income	$ 20,654	$ 15,087	$ 15,097	$ 6,765	$ 13,549	$ 14,218	$ 12,031	$ 14,919	$ 14,867	$ 10,827	$ (14,742)	$ 11,784	$ 57,603	$ 54,717	$ 22,736
Earnings per share - basic and diluted (in dollars per share)	$ 0.19	$ 0.14	$ 0.14	$ 0.06	$ 0.12	$ 0.13	$ 0.11	$ 0.13	$ 0.13	$ 0.10	$ (0.13)		$ 0.52	$ 0.49	$ 0.20
Weighted average shares outstanding - basic and diluted (in shares)	108,499,658	110,983,871	111,102,306	108,438,173	109,958,999	111,371,754	111,553,203	111,536,577	111,423,361	111,389,951	111,360,278		109,755,924	111,101,246	111,395,723

Earnings per Share (Details)

Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Net income	$ 20,654	$ 15,087	$ 15,097	$ 6,765	$ 13,549	$ 14,218	$ 12,031	$ 14,919	$ 14,867	$ 10,827	$ (14,742)	$ 11,784	$ 57,603	$ 54,717	$ 22,736
Shares:
Weighted average shares outstanding - basic (in shares)													109,755,924	111,101,246	111,395,723
Weighted average dilutive shares outstanding (in shares)													0	0	0
Weighted average shares outstanding - diluted (in shares)													109,755,924	111,101,246	111,395,723
Earnings per share:
Basic (in dollars per share)													$ 0.52	$ 0.49	$ 0.20
Diluted (in dollars per share)													$ 0.52	$ 0.49	$ 0.20

Earnings per Share - Narrative

Earnings per Share - Narrative (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Antidilutive securities excluded from computation of earnings per share (in shares)	1,413,818	1,111,650	0

Parent-only Financial Informa_3

Parent-only Financial Information - Statement of Financial Condition (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Assets
Cash and due from banks	$ 422,787	$ 75,420
Short-term investments	170	127
Total cash and cash equivalents	422,957	75,547
Debt securities available for sale, at fair value	1,316,952	1,098,336
Equity securities, at fair value	5,418	2,855
Other assets	209,852	145,708
Total assets	8,798,536	8,188,694
Liabilities:
Balance	799,364	1,407,022
Accrued expenses and other liabilities	176,691	117,806
Total liabilities	7,787,249	7,206,177
Stockholders' equity	1,011,287	982,517	$ 972,060	$ 472,070
Total liabilities and stockholders' equity	8,798,536	8,188,694
Parent Company
Assets
Cash and due from banks	94,053	168,242
Short-term investments	170	127
Total cash and cash equivalents	94,223	168,369
Debt securities available for sale, at fair value	0	1,496
Equity securities, at fair value	1,167	1,282
Investment in subsidiaries	873,629	785,964
Loans receivable, net	41,461	42,982
Other assets	9,803	8,431
Total assets	1,020,283	1,008,524
Liabilities:
Balance	6,953	23,831
Accrued expenses and other liabilities	2,043	2,176
Total liabilities	8,996	26,007
Stockholders' equity	1,011,287	982,517
Total liabilities and stockholders' equity	$ 1,020,283	$ 1,008,524

Parent-only Financial Informa_4

Parent-only Financial Information - Statement of Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest income:
Loans receivable													$ 255,236	$ 217,774	$ 189,869
Unrealized gain (loss) on debt securities available for sale													21,236	21,067	(5,778)
Interest expense on borrowings													18,892	27,161	22,733
Net interest income	$ 58,676	$ 56,324	$ 55,871	$ 50,702	$ 47,428	$ 41,716	$ 40,843	$ 42,384	$ 43,375	$ 40,583	$ 41,015	$ 39,061	221,573	172,371	164,034
Non-interest income:
Gain on securities transactions													370	2,612	116
Change in fair value of equity securities													767	305	0
Other non-interest income													6,983	5,922	4,943
Total non-interest income	9,962	7,909	7,008	6,391	8,709	10,115	6,775	6,037	6,405	5,290	5,450	4,543	31,270	31,636	21,688
Non-interest expense:
Charitable contribution to foundation													0	0	34,767
Merger-related expenses													1,931	2,755	0
Other non-interest expense													21,499	11,769	5,597
Total non-interest expense	40,810	41,378	37,443	38,508	36,237	31,064	31,841	29,559	31,013	26,590	61,768	26,015	158,139	128,701	145,386
Income before income tax expense	27,201	20,339	19,700	9,017	17,381	19,610	15,665	18,426	17,990	17,783	(17,703)	15,589	76,257	71,082	33,659
Income tax benefit	(6,547)	(5,252)	(4,603)	(2,252)	(3,832)	(5,392)	(3,634)	(3,507)	(3,123)	(6,956)	2,961	(3,805)	(18,654)	(16,365)	(10,923)
Net income	$ 20,654	$ 15,087	$ 15,097	$ 6,765	$ 13,549	$ 14,218	$ 12,031	$ 14,919	$ 14,867	$ 10,827	$ (14,742)	$ 11,784	57,603	54,717	22,736
Other comprehensive income (loss)													(890)	3,710	(6,487)
Total comprehensive income, net of tax													56,713	58,427	16,249
Parent Company
Condensed Financial Statements, Captions [Line Items]
Dividends from subsidiary													50,000	179,000	0
Interest income:
Loans receivable													2,047	2,111	1,513
Unrealized gain (loss) on debt securities available for sale													51	51	123
Interest-earning deposits													1	173	871
Total interest income													52,099	181,335	2,507
Interest expense on borrowings													863	176	3,468
Net interest income													51,236	181,159	(961)
Equity earnings (loss) in subsidiary													8,027	(123,142)	51,401
Non-interest income:
Gain on securities transactions													2	236	0
Change in fair value of equity securities													(115)	65	0
Other non-interest income													0	139	0
Total non-interest income													(113)	440	0
Non-interest expense:
Charitable contribution to foundation													0	0	34,767
Merger-related expenses													280	1,807	0
Other non-interest expense													1,377	1,955	425
Total non-interest expense													1,657	3,762	35,192
Income before income tax expense													57,493	54,695	15,248
Income tax benefit													110	22	7,488
Net income													57,603	54,717	22,736
Other comprehensive income (loss)													(890)	3,710	(6,487)
Total comprehensive income, net of tax													$ 56,713	$ 58,427	$ 16,249

Parent-only Financial Informa_5

Parent-only Financial Information - Statement of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net income	$ 20,654	$ 15,087	$ 15,097	$ 6,765	$ 13,549	$ 14,218	$ 12,031	$ 14,919	$ 14,867	$ 10,827	$ (14,742)	$ 11,784	$ 57,603	$ 54,717	$ 22,736
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of debt issuance costs													0	0	890
Amortization of intangible assets													1,048	222	0
Gain on securities transactions													(370)	(2,612)	(116)
Change in fair value of equity securities													(767)	(305)	0
Deferred tax expense (benefit)													9,738	7,527	(5,490)
(Increase) in other assets													(75,127)	(51,856)	(11,053)
Increase in accrued expenses and other liabilities													32,891	3,032	7,980
Contribution of common stock to Columbia Bank Foundation													0	0	34,767
Net cash provided by operating activities													47,886	21,824	56,594
Cash flows from investing activities:
Proceeds from sales of equity securities													0	1,065	0
Proceeds from paydown/maturities/calls of debt securities available for sale													247,908	149,683	69,977
Purchases of debt securities available for sale													(292,809)	(176,171)	(413,804)
Purchases of equity securities													0	(416)	0
Repayment of loan receivable from Bank													35,613	11,671	32,039
Net cash acquired in acquisitions													155,248	(31,288)	0
Net cash provided by (used in) investing activities													257,645	(521,014)	(943,149)
Cash flows from financing activities:
Purchase of treasury stock													(108,166)	(55,309)	0
Restricted stock forfeitures													(24)	(736)	0
Restricted stock repurchased on vesting to pay taxes													(174)	0	0
Issuance of treasury stock allocated to restricted stock award grants													0	1,095	0
Net cash provided by financing activities													41,879	532,536	863,258
Net increase (decrease) in cash and cash equivalents													347,410	33,346	(23,297)
Cash and cash equivalents at beginning of period				75,547				42,201				65,498	75,547	42,201	65,498
Cash and cash equivalents at end of period	422,957				75,547				42,201				422,957	75,547	42,201
Non-cash assets acquired:
Equity securities													1,796	1,073	0
Other assets													1,489	767	0
Total non-cash assets acquired													271,958	856,640	0
Liabilities assumed:
Borrowings													37,728	82,761	0
Total liabilities assumed													377,344	880,399	0
Net non-cash liabilities acquired													(105,386)	(23,759)	0
Net cash and cash equivalents acquired in acquisitions													155,248	105,006	0
Parent Company
Cash flows from operating activities:
Net income													57,603	54,717	22,736
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of debt issuance costs													0	0	890
Amortization of intangible assets													(278)	(71)	0
Gain on securities transactions													(2)	(236)	0
Change in fair value of equity securities													115	(65)	0
Deferred tax expense (benefit)													1,411	1,453	(6,086)
(Increase) in other assets													(2,675)	(2,026)	1,515
Increase in accrued expenses and other liabilities													(647)	3,515	(1,498)
Contribution of common stock to Columbia Bank Foundation													0	0	34,767
Equity in undistributed (earnings) loss of subsidiary													(8,027)	123,142	(51,401)
Net cash provided by operating activities													47,500	180,429	923
Cash flows from investing activities:
Capital contribution to subsidiary													0	0	(246,420)
Proceeds from sales of equity securities													0	1,065	0
Proceeds from paydown/maturities/calls of debt securities available for sale													1,498	500	1,601
Purchases of debt securities available for sale													0	0	(414)
Purchases of equity securities													0	(416)	0
Loan to ESOP													0	0	(45,428)
Repayment of loan receivable from Bank													1,521	1,457	989
Net cash acquired in acquisitions													0	(135,410)	0
Net cash provided by (used in) investing activities													3,019	(132,804)	(289,672)
Cash flows from financing activities:
Payments of subordinated debt and trust preferred securities													(16,600)	0	(51,547)
Issuance of common stock in initial public offering													0	0	492,428
Purchase of treasury stock													(108,166)	(55,309)	0
Issuance of common stock allocated to restricted stock award grants													0	21,687	0
Restricted stock forfeitures													(199)	(736)	0
Restricted stock repurchased on vesting to pay taxes													(181)	0	0
Issuance of treasury stock allocated to restricted stock award grants													481	1,269	0
Net cash provided by financing activities													(124,665)	(33,089)	440,881
Net increase (decrease) in cash and cash equivalents													(74,146)	14,536	152,132
Cash and cash equivalents at beginning of period				$ 168,369				$ 153,833				$ 1,701	168,369	153,833	1,701
Cash and cash equivalents at end of period	$ 94,223				$ 168,369				$ 153,833				94,223	168,369	153,833
Non-cash assets acquired:
Debt securities available for sale													0	1,998	0
Equity securities													0	208	0
Other assets													0	1,492	0
Total non-cash assets acquired													0	3,698	0
Liabilities assumed:
Borrowings													0	23,901	0
Total liabilities assumed													0	23,901	0
Net non-cash liabilities acquired													0	(20,203)	0
Net cash and cash equivalents acquired in acquisitions													$ 0	$ 884	$ 0

Other Comprehensive Income (L_3

Other Comprehensive Income (Loss) - Tax effects of components in other comprehensive income (loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Before Tax
Other comprehensive income (loss)	$ (1,122)	$ 4,690	$ (7,378)
Tax Effect
Other comprehensive income (loss)	232	(980)	891
After Tax
Total other comprehensive (loss) income	(890)	3,710	(6,487)
Unrealized Gains on Debt Securities Available for Sale
Before Tax
Other comprehensive income (loss), before reclassifications	26,876	26,601	(7,224)
Other comprehensive income (loss)	27,406	29,224	(7,353)
Tax Effect
Other comprehensive income (loss), before reclassifications	(5,640)	(5,534)	1,446
Other comprehensive income (loss)	(5,755)	(6,137)	1,470
After Tax
Other comprehensive income (loss), before reclassifications	21,236	21,067	(5,778)
Total other comprehensive (loss) income	21,651	23,087	(5,883)
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Accretion Of Unrealized Gains (Losses), Parent
Before Tax
Reclassification from AOCI, current period	160	11	(13)
Tax Effect
Reclassification from AOCI, current period	(34)	(2)	0
After Tax
Reclassification from AOCI, current period	126	9	(13)
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Other Reclassifications, Parent
Before Tax
Reclassification from AOCI, current period	370	2,612	(116)
Tax Effect
Reclassification from AOCI, current period	(81)	(601)	24
After Tax
Reclassification from AOCI, current period	289	2,011	(92)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
Before Tax
Other comprehensive income (loss), before reclassifications	(10,605)	(8,193)	(2,825)
Tax Effect
Other comprehensive income (loss), before reclassifications	2,223	1,725	595
After Tax
Other comprehensive income (loss), before reclassifications	(8,382)	(6,468)	(2,230)
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent
Before Tax
Reclassification from AOCI, current period	(56)	(56)	(623)
Tax Effect
Reclassification from AOCI, current period	12	12	132
After Tax
Reclassification from AOCI, current period	(44)	(44)	(491)
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent
Before Tax
Reclassification from AOCI, current period	(4,284)	(3,709)	2,526
Tax Effect
Reclassification from AOCI, current period	900	779	(530)
After Tax
Reclassification from AOCI, current period	(3,384)	(2,930)	1,996
Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Before Tax
Other comprehensive income (loss), before reclassifications	(13,583)	(12,576)	897
Other comprehensive income (loss)	(17,923)	(16,341)	2,800
Tax Effect
Other comprehensive income (loss), before reclassifications	2,852	2,641	(776)
Other comprehensive income (loss)	3,764	3,432	(1,174)
After Tax
Other comprehensive income (loss), before reclassifications	(10,731)	(9,935)	121
Total other comprehensive (loss) income	$ (14,159)	$ (12,909)	$ 1,626

Other Comprehensive Income (L_4

Other Comprehensive Income (Loss) - Changes in components of other comprehensive income (loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	$ 982,517	$ 972,060	$ 472,070
Current period changes in other comprehensive income (loss)	(890)	3,710	(6,487)
Balance at end of year	1,011,287	982,517	972,060
Cumulative Effect, Period of Adoption, Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period		0
Balance at end of year			0
Cumulative Effect, Period of Adoption, Adjusted Balance
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period		972,060
Balance at end of year			972,060
Accumulated Other Comprehensive (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(68,735)	(71,897)	(65,410)
Current period changes in other comprehensive income (loss)	(890)	3,710	(6,487)
Current period changes in other comprehensive (loss) income			(6,487)
Balance at end of year	(69,625)	(68,735)	(71,897)
Accumulated Other Comprehensive (Loss) | Cumulative Effect, Period of Adoption, Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period		(548)
Balance at end of year			(548)
Accumulated Other Comprehensive (Loss) | Cumulative Effect, Period of Adoption, Adjusted Balance
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(68,735)	(72,445)
Balance at end of year		(68,735)	(72,445)
Unrealized Gains on Debt Securities Available for Sale
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	9,377	(13,162)	(7,279)
Current period changes in other comprehensive income (loss)	21,651	23,087	(5,883)
Current period changes in other comprehensive (loss) income			(5,883)
Balance at end of year	31,028	9,377	(13,162)
Unrealized Gains on Debt Securities Available for Sale | Cumulative Effect, Period of Adoption, Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period		(548)
Balance at end of year			(548)
Unrealized Gains on Debt Securities Available for Sale | Cumulative Effect, Period of Adoption, Adjusted Balance
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	9,377	(13,710)
Balance at end of year		9,377	(13,710)
Unrealized (Losses) on Swaps
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(8,474)	(2,006)	224
Current period changes in other comprehensive income (loss)	(8,382)	(6,468)
Current period changes in other comprehensive (loss) income			(2,230)
Balance at end of year	(16,856)	(8,474)	(2,006)
Unrealized (Losses) on Swaps | Cumulative Effect, Period of Adoption, Adjusted Balance
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(8,474)	(2,006)
Balance at end of year		(8,474)	(2,006)
Employee Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(69,638)	(56,729)	(58,355)
Current period changes in other comprehensive income (loss)	(14,159)	(12,909)	1,626
Current period changes in other comprehensive (loss) income			1,626
Balance at end of year	(83,797)	(69,638)	(56,729)
Employee Benefit Plans | Cumulative Effect, Period of Adoption, Adjusted Balance
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	$ (69,638)	(56,729)
Balance at end of year		$ (69,638)	$ (56,729)

Other Comprehensive Income (L_5

Other Comprehensive Income (Loss) - Reclassification out of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Gain on securities transactions													$ 370	$ 2,612	$ 116
Other non-interest expense													21,499	11,769	5,597
Income before income tax expense	$ 27,201	$ 20,339	$ 19,700	$ 9,017	$ 17,381	$ 19,610	$ 15,665	$ 18,426	$ 17,990	$ 17,783	$ (17,703)	$ 15,589	76,257	71,082	33,659
Income (tax) benefit	(6,547)	(5,252)	(4,603)	(2,252)	(3,832)	(5,392)	(3,634)	(3,507)	(3,123)	(6,956)	2,961	(3,805)	(18,654)	(16,365)	(10,923)
Net income	$ 20,654	$ 15,087	$ 15,097	$ 6,765	$ 13,549	$ 14,218	$ 12,031	$ 14,919	$ 14,867	$ 10,827	$ (14,742)	$ 11,784	57,603	54,717	22,736
Accumulated Other Comprehensive (Loss) Income Components
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income before income tax expense													(3,914)	(1,097)	2,410
Income (tax) benefit													819	178	(506)
Net income													(3,095)	(919)	1,904
Accumulated Other Comprehensive (Loss) Income Components | Reclassification adjustment for gains (losses) included in net income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Gain on securities transactions													370	2,612	(116)
Accumulated Other Comprehensive (Loss) Income Components | Reclassification adjustment of actuarial net (loss) gain included in net income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other non-interest expense													$ (4,284)	$ (3,709)	$ 2,526

Derivatives and Hedging Activ_3

Derivatives and Hedging Activities - Narrative (Details)	12 Months Ended
	Dec. 31, 2020USD ($)swap	Dec. 31, 2019USD ($)swap	Dec. 31, 2018USD ($)
Derivative [Line Items]
Accrued interest on derivative, at fair value	$ 1,000,000	$ 344,000
Net liability position	21,900,000
Collateral against obligations	41,200,000
Interest rate swaps
Derivative [Line Items]
Derivative gains (losses) recorded in the Statements of Income	(306,000)	204,000	$ (52,000)
FHLB advances | Interest rate swaps
Derivative [Line Items]
Notional amount of derivative	430,000,000	410,000,000
Not-designated hedge | Currency forward contract - non-designated hedge
Derivative [Line Items]
Notional amount of derivative	0	0
Not-designated hedge | Interest rate swaps
Derivative [Line Items]
Notional amount of derivative	$ 175,100,000	$ 169,900,000
Number of commercial banking customers | swap	48	22
Designated as hedging instrument | FHLB advances | Interest rate swaps
Derivative [Line Items]
Notional amount of derivative	$ 430,000,000	$ 410,000,000
Number of interest rate derivatives held | swap	31	29

Derivatives and Hedging Activ_4

Derivatives and Hedging Activities - Derivative Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Interest rate swaps | Designated as hedging instrument | Other Assets
Derivatives, Fair Value [Line Items]
Derivative assets	$ 19,425	$ 185
Interest rate swaps | Designated as hedging instrument | Other Liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	42,384	11,546
Carrying Value
Derivatives, Fair Value [Line Items]
Derivative assets	19,425	185
Derivative liabilities	$ 42,384	$ 11,546

Revenue Recognition (Details)

Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Total out-of-scope non-interest income													$ 16,131	$ 17,333	$ 8,725
Total non-interest income	$ 9,962	$ 7,909	$ 7,008	$ 6,391	$ 8,709	$ 10,115	$ 6,775	$ 6,037	$ 6,405	$ 5,290	$ 5,450	$ 4,543	31,270	31,636	21,688
Deposit Account, Title Insurance And Other Non-Interest Income
Disaggregation of Revenue [Line Items]
Revenue													15,139	14,303	12,963
Demand deposit account fees
Disaggregation of Revenue [Line Items]
Revenue													3,633	4,478	3,987
Title insurance fees
Disaggregation of Revenue [Line Items]
Revenue													5,034	4,981	4,297
Other non-interest income
Disaggregation of Revenue [Line Items]
Revenue													$ 6,472	$ 4,844	$ 4,679