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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-6

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-5

+ Details

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

- Definition

Amortized cost excluding accrued interest, of financing receivable originated more than five years prior to current fiscal year. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 79
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-79

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-6

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B

+ Details

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

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable originated more than five years before current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amortized cost excluding accrued interest, of financing receivable that can be withdrawn, repaid, and redrawn.

+ References

+ Details

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

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable that can be withdrawn, repaid, and redrawn.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amortized cost excluding accrued interest, of financing receivable originated four years prior to current fiscal year. Excludes net investment in lease.

+ References

+ Details

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

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable originated four years before current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amortized cost excluding accrued interest, of financing receivable originated three years prior to current fiscal year. Excludes net investment in lease.

+ References

+ Details

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

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable originated three years before current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amortized cost excluding accrued interest, of financing receivable originated in current fiscal year. Excludes net investment in lease.

+ References

+ Details

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

- Definition

Amortized cost excluding accrued interest, of financing receivable originated two years prior to current fiscal year. Excludes net investment in lease.

+ References

+ Details

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

- Definition

Amortized cost excluding accrued interest of financing receivable originated in fiscal year prior to current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 29
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-29

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-5

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 79
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-79

+ Details

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

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancialAssetNotPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=bcml_ConstructionAndLandPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InternalCreditAssessmentAxis=us-gaap_PassMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InternalCreditAssessmentAxis=us-gaap_SpecialMentionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InternalCreditAssessmentAxis=us-gaap_SubstandardMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

LOANS - Risk Grade (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
LOANS - Risk Grade (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
LOANS
2025/2024	$ 321,064		$ 321,064		$ 283,164
2024/2023	265,456		265,456		109,753
2023/2022	91,266		91,266		398,356
2022/2021	372,597		372,597		501,684
2021/2020	424,800		424,800		133,453
2020/Prior	535,443		535,443		499,496
Revolving loans amortized cost	31,057		31,057		26,841
Loans Receivable, Gross, Commercial, Real Estate, Total	2,041,683		2,041,683		1,952,747
Total	839	$ 1,598	1,040	$ 5,161
Financial asset, not past due
LOANS
2022/2021					3,434
Loans Receivable, Gross, Commercial, Real Estate, Total	2,016,846		2,016,846		1,918,635
2021/2020					45
2020/Prior			1,040		1,685
Revolving loans amortized cost					1
Total			1,040		5,165
Commercial and industrial
LOANS
2025/2024	29,078		29,078		54,870
2024/2023	51,084		51,084		20,468
2023/2022	15,821		15,821		20,759
2022/2021	17,741		17,741		11,879
2021/2020	8,028		8,028		14,617
2020/Prior	31,228		31,228		31,148
Revolving loans amortized cost	24,270		24,270		20,207
Loans Receivable, Gross, Commercial, Real Estate, Total	177,250		177,250		173,948
Total		1,031	193	1,387
Commercial and industrial \| Financial asset, not past due
LOANS
2022/2021					1,021
Loans Receivable, Gross, Commercial, Real Estate, Total	175,681		175,681		172,704
2021/2020					45
2020/Prior			193		324
Total			193		1,390
Construction and land
LOANS
2025/2024					10
2024/2023	4,742		4,742
2022/2021					128
2021/2020	119		119		1,090
2020/Prior	263		263		287
Loans Receivable, Gross, Commercial, Real Estate, Total	5,124		5,124		1,515
Construction and land \| Financial asset, not past due
LOANS
Loans Receivable, Gross, Commercial, Real Estate, Total	5,124		5,124		1,509
Commercial real estate
LOANS
2025/2024	247,443		247,443		196,303
2024/2023	182,898		182,898		89,231
2023/2022	75,417		75,417		377,562
2022/2021	354,835		354,835		452,154
2021/2020	384,510		384,510		116,292
2020/Prior	496,299		496,299		434,179
Revolving loans amortized cost	1,866		1,866		1,510
Loans Receivable, Gross, Commercial, Real Estate, Total	1,743,268		1,743,268		1,667,231
Total	839	566	839	3,772
Commercial real estate \| Financial asset, not past due
LOANS
Loans Receivable, Gross, Commercial, Real Estate, Total	1,720,840		1,720,840		1,635,499
2022/2021					2,413
2020/Prior			839		1,359
Total			839		3,772
Residential
LOANS
2025/2024	44,227		44,227		31,828
2024/2023	26,603		26,603
2022/2021					37,513
2021/2020	32,133		32,133		1,452
2020/Prior	7,541		7,541		33,748
Revolving loans amortized cost	4,788		4,788		5,121
Loans Receivable, Gross, Commercial, Real Estate, Total	115,292		115,292		109,662
Total			1
Residential \| Financial asset, not past due
LOANS
Loans Receivable, Gross, Commercial, Real Estate, Total	114,452		114,452		108,538
2020/Prior			1
Total			1
Consumer
LOANS
2025/2024	316		316		153
2024/2023	129		129		54
2023/2022	28		28		35
2022/2021	21		21		10
2021/2020	10		10		2
2020/Prior	112		112		134
Revolving loans amortized cost	133		133		3
Loans Receivable, Gross, Commercial, Real Estate, Total	749		749		391
Total		$ 1	7	$ 2
Consumer \| Financial asset, not past due
LOANS
Loans Receivable, Gross, Commercial, Real Estate, Total	749		749		385
2020/Prior			7		2
Revolving loans amortized cost					1
Total			7		3
Pass
LOANS
2025/2024	321,064		321,064		283,014
2024/2023	265,456		265,456		108,967
2023/2022	85,649		85,649		392,113
2022/2021	341,027		341,027		481,214
2021/2020	391,184		391,184		113,023
2020/Prior	449,609		449,609		432,196
Revolving loans amortized cost	30,694		30,694		26,253
Loans Receivable, Gross, Commercial, Real Estate, Total	1,884,683		1,884,683		1,836,780
Pass \| Commercial and industrial
LOANS
2025/2024	29,078		29,078		54,720
2024/2023	51,084		51,084		20,314
2023/2022	15,667		15,667		20,759
2022/2021	17,741		17,741		11,823
2021/2020	7,973		7,973		13,433
2020/Prior	29,228		29,228		28,708
Revolving loans amortized cost	23,984		23,984		19,699
Loans Receivable, Gross, Commercial, Real Estate, Total	174,755		174,755		169,456
Pass \| Construction and land
LOANS
2025/2024					10
2024/2023	4,742		4,742
2022/2021					128
2021/2020	119		119		1,090
2020/Prior	263		263		287
Loans Receivable, Gross, Commercial, Real Estate, Total	5,124		5,124		1,515
Pass \| Commercial real estate
LOANS
2025/2024	247,443		247,443		196,303
2024/2023	182,898		182,898		88,599
2023/2022	69,954		69,954		371,319
2022/2021	323,265		323,265		432,629
2021/2020	350,993		350,993		97,046
2020/Prior	413,211		413,211		370,828
Revolving loans amortized cost	1,866		1,866		1,510
Loans Receivable, Gross, Commercial, Real Estate, Total	1,589,630		1,589,630		1,558,234
Pass \| Residential
LOANS
2025/2024	44,227		44,227		31,828
2024/2023	26,603		26,603
2022/2021					36,624
2021/2020	32,089		32,089		1,452
2020/Prior	6,795		6,795		32,245
Revolving loans amortized cost	4,711		4,711		5,041
Loans Receivable, Gross, Commercial, Real Estate, Total	114,425		114,425		107,190
Pass \| Consumer
LOANS
2025/2024	316		316		153
2024/2023	129		129		54
2023/2022	28		28		35
2022/2021	21		21		10
2021/2020	10		10		2
2020/Prior	112		112		128
Revolving loans amortized cost	133		133		3
Loans Receivable, Gross, Commercial, Real Estate, Total	749		749		385
Special mention
LOANS
2024/2023					632
2023/2022					6,243
2022/2021	31,570		31,570		11,377
2021/2020	18,793		18,793		18,250
2020/Prior	52,511		52,511		46,470
Revolving loans amortized cost	13		13		280
Loans Receivable, Gross, Commercial, Real Estate, Total	102,887		102,887		83,252
Special mention \| Commercial and industrial
LOANS
2022/2021					56
2020/Prior	1,122		1,122		1,969
Revolving loans amortized cost					200
Loans Receivable, Gross, Commercial, Real Estate, Total	1,122		1,122		2,225
Special mention \| Commercial real estate
LOANS
2024/2023					632
2023/2022					6,243
2022/2021	31,570		31,570		10,462
2021/2020	18,793		18,793		18,250
2020/Prior	51,389		51,389		44,089
Loans Receivable, Gross, Commercial, Real Estate, Total	101,752		101,752		79,676
Special mention \| Residential
LOANS
2022/2021					859
2020/Prior					410
Revolving loans amortized cost	13		13		80
Loans Receivable, Gross, Commercial, Real Estate, Total	13		13		1,349
Special mention \| Consumer
LOANS
2020/Prior					2
Loans Receivable, Gross, Commercial, Real Estate, Total					2
Substandard
LOANS
2025/2024					150
2024/2023					154
2023/2022	5,617		5,617
2022/2021					9,093
2021/2020	14,823		14,823		2,180
2020/Prior	33,323		33,323		20,830
Revolving loans amortized cost	350		350		308
Loans Receivable, Gross, Commercial, Real Estate, Total	54,113		54,113		32,715
Substandard \| Commercial and industrial
LOANS
2025/2024					150
2024/2023					154
2023/2022	154		154
2021/2020	55		55		1,184
2020/Prior	878		878		471
Revolving loans amortized cost	286		286		308
Loans Receivable, Gross, Commercial, Real Estate, Total	1,373		1,373		2,267
Substandard \| Commercial real estate
LOANS
2023/2022	5,463		5,463
2022/2021					9,063
2021/2020	14,724		14,724		996
2020/Prior	31,699		31,699		19,262
Loans Receivable, Gross, Commercial, Real Estate, Total	51,886		51,886		29,321
Substandard \| Residential
LOANS
2022/2021					30
2021/2020	44		44
2020/Prior	746		746		1,093
Revolving loans amortized cost	64		64
Loans Receivable, Gross, Commercial, Real Estate, Total	$ 854		$ 854		1,123
Substandard \| Consumer
LOANS
2020/Prior					4
Loans Receivable, Gross, Commercial, Real Estate, Total					$ 4