Fair Value Measurements - Carrying Value and Estimated Fair Value of Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities held-to-maturity, Carrying/Notional Amount	$ 28,154us-gaap_HeldToMaturitySecurities	$ 28,123us-gaap_HeldToMaturitySecurities
Loans, net, Carrying/Notional Amount	1,355,781	1,329,865
Mortgage loans held-for-sale, Carrying/Notional Amount	11,983	9,466
Deposits and securities sold under agreements to repurchase, Carrying/Notional Amount	1,704,954	1,663,707
Commitments to extend credit, Carrying/Notional Amount	0us-gaap_UnusedCommitmentsToExtendCredit	0us-gaap_UnusedCommitmentsToExtendCredit
Standby letters of credit, Carrying/Notional Amount	0	0
Securities held-to-maturity	28,389	28,400
Loans, net, Estimated Fair Value	1,373,614	1,346,569
Mortgage loans held-for-sale	11,983us-gaap_LoansReceivableHeldForSaleNet	9,466us-gaap_LoansReceivableHeldForSaleNet
Deposits and securities sold under agreements to repurchase, Estimated Fair Value	1,581,942	1,530,607
Commitments to extend credit, Estimated Fair Value	0	0
Standby letters of credit, Estimated Fair Value	0wbhc_StandbyLettersOfCreditAtFairValue	0wbhc_StandbyLettersOfCreditAtFairValue
Quoted Market Prices in an Active Market (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commitments to extend credit, Estimated Fair Value	0	0
Standby letters of credit, Estimated Fair Value	0	0
Models with Significant Observable Market Parameters (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities held-to-maturity	28,389	28,400
Commitments to extend credit, Estimated Fair Value	0	0
Standby letters of credit, Estimated Fair Value	0	0
Models with Significant Unobservable Market Parameters (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net, Estimated Fair Value	1,373,614	1,346,569
Mortgage loans held-for-sale	11,983	9,466
Deposits and securities sold under agreements to repurchase, Estimated Fair Value	1,581,942	1,530,607
Commitments to extend credit, Estimated Fair Value	0	0
Standby letters of credit, Estimated Fair Value	$ 0	$ 0

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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 5

-Subparagraph (f)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (c)

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 5

-Subparagraph (a)

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.1)

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.6)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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- Definition

Fair value of investments in debt securities classified as held-to-maturity.

+ References

+ Details

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- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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- Definition

Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

+ References

+ Details

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- Definition

Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

+ References

No definition available.

+ Details

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- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Glossary Loan

-URI http://asc.fasb.org/extlink&oid=6517073

+ Details

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- Definition

Amount classified as loans attributable to disposal group held for sale or disposed of. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4428-111522

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 7

-Subparagraph a

-Article 9

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.7(a))

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 948

-SubTopic 310

-Section 30

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- Definition

Unused amount of commitments to extend credit to customers.

+ References

No definition available.

+ Details

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

- Definition

Unused amount of commitments to extend credit to customers, measured at fair value.

+ References

No definition available.

+ Details

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- Definition

Deposits and securities sold under agreements to repurchase carrying amount.

+ References

No definition available.

+ Details

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Namespace Prefix:	wbhc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents deposits and securities sold under agreements to repurchase as of the balance sheet date.

+ References

No definition available.

+ Details

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

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date, stated at fair value.

+ References

No definition available.

+ Details

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