Commitments and Contingent Liabilities - Total Contractual Amount for All Off-Balance Sheet Commitments (Detail) $ in Thousands	Sep. 30, 2018 USD ($)
Standby letters of credit
Loss Contingencies [Line Items]
Contractual amount for off-balance sheet commitments	$ 89,331
Commitments to extend credit
Loss Contingencies [Line Items]
Contractual amount for off-balance sheet commitments	$ 595,450

The contractual amount associated with the obligations, contingent liabilities, and other exposures relating to off-balance sheet arrangements such as unfunded loan commitments, contractual obligations, and recourse from loans securitized.

No definition available.

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