Allowance for Credit Losses - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated	$ 16,268	$ 20,261
Collectively evaluated	7,766,319	5,954,950
Acquired with deteriorated credit quality	83,463	937
Loans	7,866,050	5,976,148
Individually evaluated	4,091	4,251
Collectively evaluated	66,173	53,796
Total	70,264	58,047	$ 71,124
Non-owner occupied commercial
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated	0	3,063
Collectively evaluated	2,871,950	2,313,047
Acquired with deteriorated credit quality	34,064	174
Loans	2,906,014	2,316,284
Individually evaluated	753	0
Collectively evaluated	22,709	20,071
Total	23,462	20,071	25,910
Owner occupied commercial
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated	12,041	6,678
Collectively evaluated	1,202,919	901,638
Acquired with deteriorated credit quality	31,229	133
Loans	1,246,189	908,449
Individually evaluated	983	69
Collectively evaluated	5,713	3,895
Total	6,696	3,964	3,955
Multifamily
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated	0	0
Collectively evaluated	1,254,412	972,233
Acquired with deteriorated credit quality	6,402	0
Loans	1,260,814	972,233
Individually evaluated	5	0
Collectively evaluated	9,420	8,309
Total	9,425	8,309	7,253
Non-owner occupied residential
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated	441	2,567
Collectively evaluated	216,516	174,463
Acquired with deteriorated credit quality	1,069	67
Loans	218,026	177,097
Individually evaluated	16	0
Collectively evaluated	2,627	2,380
Total	2,643	2,380	3,321
Commercial, industrial and other
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated	2,806	6,537
Collectively evaluated	594,568	455,306
Acquired with deteriorated credit quality	9,337	563
Loans	606,711	462,406
Individually evaluated	2,150	4,182
Collectively evaluated	6,686	5,709
Total	8,836	9,891	13,665
Construction
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated	980	0
Collectively evaluated	379,120	302,228
Acquired with deteriorated credit quality	0	0
Loans	380,100	302,228
Individually evaluated	0	0
Collectively evaluated	2,968	838
Total	2,968	838	786
Equipment finance
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated	0	0
Collectively evaluated	151,574	123,212
Acquired with deteriorated credit quality	0	0
Loans	151,574	123,212
Individually evaluated	0	0
Collectively evaluated	3,445	3,663
Total	3,445	3,663	6,552
Residential mortgage
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated	0	1,416
Collectively evaluated	764,340	437,294
Acquired with deteriorated credit quality	1,212	0
Loans	765,552	438,710
Individually evaluated	181	0
Collectively evaluated	7,860	3,914
Total	8,041	3,914	3,623
Consumer
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated	0	0
Collectively evaluated	330,920	275,529
Acquired with deteriorated credit quality	150	0
Loans	331,070	275,529
Individually evaluated	3	0
Collectively evaluated	4,745	5,017
Total	$ 4,748	$ 5,017	$ 6,059

Financing Receivable, Acquired With Credit Deterioration

No definition available.

Name:	lbai_FinancingReceivableAcquiredWithCreditDeterioration
Namespace Prefix:	lbai_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The balance of financing receivables that were collectively evaluated for impairment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524

+ Details

Name:	us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919230-210447

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 3B
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL120267963-210447

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The balance of financing receivables that were individually evaluated for impairment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524

+ Details

Name:	us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=lbai_NonOwnerOccupiedCommercialMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=lbai_OwnerOccupiedCommercialMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=srt_MultifamilyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=lbai_NonOwnerOccupiedResidentialMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=lbai_CommercialIndustrialAndOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConstructionLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=lbai_EquipmentFinancingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ResidentialMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConsumerLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: