Employee Benefit Plan, Description of Plan (Details) - EBP 001	12 Months Ended
Dec. 31, 2025 USD ($)
EBP, Description of Plan [Line Items]
EBP, Participant Contribution, Pretax, Maximum Annual Compensation to Total Compensation, Percentage	100.00%
EBP, Employer Contribution, Participant Compensation Matched, Percentage	100.00%
EBP, Employer Contribution, Matching Percentage	6.00%
Employee Benefit Plan, Employer Contribution, Matching Amount	$ 1,043,126
Defined Contribution Plan, Employer Discretionary Contribution percent	4.00%
EBP, Employer Discretionary Contribution, Amount	$ 670,933
EBP, Note Receivable from Participant, Account, Minimum Borrowing, Amount	1,000
EBP, Note Receivable from Participant, Account, Maximum Borrowing, Amount	$ 50,000
EBP, Note Receivable from Participant, Account, Maximum Borrowing, to Total Account, Percentage	50.00%
EBP, Payment of Benefit, Lump Sum Payout Requirement Maximum	$ 7,000
EBP, Minimum Amount of Vested Benefits For Installment Payments	7,000
EBP, Forfeited Nonvested Account, Decrease from Administrative Expense	$ 500
Minimum
EBP, Description of Plan [Line Items]
EBP, Asset Held for Investment, Participant Loan, Interest Rate	5.25%
Maximum
EBP, Description of Plan [Line Items]
EBP, Asset Held for Investment, Participant Loan, Interest Rate	10.50%

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.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

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Period Type:	duration

- Definition

Percentage of employer matching contribution on eligible participant contribution to employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 962
-SubTopic 325
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478873/962-325-55-17

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Percentage of participant compensation eligible for employer matching contribution for participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

+ Details

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Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of decrease in forfeited nonvested account of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) from administrative expense.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (j)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6A-04(5)(c))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477804/962-205-S99-1

+ Details

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Period Type:	duration

- Definition

Amount of maximum account balance that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) can borrow.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage of maximum account balance that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) can borrow to total participant account balance.

+ References

+ Details

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- Definition

Amount of minimum account balance that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) can borrow.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

Percentage of maximum pretax annual compensation that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), is permitted to contribute to total pretax annual compensation.

+ References

+ Details

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Period Type:	duration

- Definition

Interest rate on participant loan in schedule of asset held for investment of employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Employee Retirement Income Security Act of 1974
-Number 2520
-Section 103
-Subsection 10
-Paragraph b
-Subparagraph (1)(i)(D)
-Publisher DOL-EBSA

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6A-05(a)(Schedule I))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477804/962-205-S99-1

+ Details

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Period Type:	duration

- Definition

Amount of employer matching contribution on eligible participant contribution to employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

No definition available.

+ Details

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Namespace Prefix:	wtba_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

EBP, Employer Discretionary Contribution, Amount

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

EBP, Employer Discretionary Contribution, percent of salaries

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The minimum vested balance required where a participant may elect to receive the benefit as a lump sum or in installment payments

+ References

No definition available.

+ Details

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Namespace Prefix:	wtba_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The maximum amount of vested account benefit balance which is required to be paid out in a lump sum

+ References

No definition available.

+ Details

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Balance Type:	debit
Period Type:	instant

- Details

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