Loans and Allowance for Loan Losses - Schedule of Details on Loans of Company (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Mortgage Loans on real estate
Total mortgage loans on real estate	$ 1,299,439us-gaap_MortgageLoansOnRealEstate	$ 1,273,553us-gaap_MortgageLoansOnRealEstate
Commercial loans	30,357	30,000
Agricultural loans	1,559wbhc_AgricultureLoans	1,670wbhc_AgricultureLoans
Consumer installment loans
Total consumer installment loans	40,812	41,025
Other loans	10,615	10,530
Gross Loan and Leases Receivable	1,382,782	1,356,778
Net deferred loan fees	(4,503)	(4,341)
Total loans	1,378,279	1,352,437
Less: Allowance for loan losses	(22,498)	(22,572)	(22,935)
Net Loans	1,355,781	1,329,865
Residential 1-4 Family [Member]
Mortgage Loans on real estate
Total mortgage loans on real estate	352,539	350,758
Consumer installment loans
Gross Loan and Leases Receivable	352,539	350,758
Less: Allowance for loan losses	(5,561)	(5,582)	(4,935)
Multifamily [Member]
Mortgage Loans on real estate
Total mortgage loans on real estate	40,546	31,242
Consumer installment loans
Gross Loan and Leases Receivable	40,546	31,242
Less: Allowance for loan losses	(223)	(172)	(77)
Commercial Real Estate [Member]
Mortgage Loans on real estate
Total mortgage loans on real estate	564,943	564,965
Consumer installment loans
Gross Loan and Leases Receivable	564,943	564,965
Less: Allowance for loan losses	(8,644)	(9,578)	(10,918)
Construction [Member]
Mortgage Loans on real estate
Total mortgage loans on real estate	257,936	245,830
Consumer installment loans
Gross Loan and Leases Receivable	257,936	245,830
Less: Allowance for loan losses	(6,315)	(5,578)	(5,159)
Farmland [Member]
Mortgage Loans on real estate
Total mortgage loans on real estate	30,879	30,236
Consumer installment loans
Gross Loan and Leases Receivable	30,879	30,236
Less: Allowance for loan losses	(710)	(795)	(618)
Second Mortgages [Member]
Mortgage Loans on real estate
Total mortgage loans on real estate	8,868	9,026
Consumer installment loans
Gross Loan and Leases Receivable	8,868	9,026
Less: Allowance for loan losses	(93)	(61)	(205)
Equity Lines of Credit [Member]
Mortgage Loans on real estate
Total mortgage loans on real estate	43,728	41,496
Consumer installment loans
Gross Loan and Leases Receivable	43,728	41,496
Less: Allowance for loan losses	(339)	(304)	(300)
Personal [Member]
Consumer installment loans
Total consumer installment loans	37,825	37,745
Credit Cards [Member]
Consumer installment loans
Total consumer installment loans	$ 2,987	$ 3,280

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount of deferred interest and fee income, unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of acquired loans. Excludes amounts for loans and leases covered under loss sharing agreements.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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Reflects the aggregate gross carrying amount of all commercial loans and leases held in portfolio, prior to deducting deferred income and the allowance for losses on commercial loans and leases.

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Reflects the aggregate gross carrying amount of all consumer loans and leases held in portfolio, prior to deducting deferred income and the allowance for losses on consumer loans and leases.

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Reflects the aggregate gross carrying amount of all loans and leases held in portfolio, not otherwise categorized (such as commercial, consumer, or foreign), prior to deducting deferred income and the allowance for losses on loans and leases, not otherwise categorized (such as commercial, consumer, or foreign).

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Amount before allowance and after 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.

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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.

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Total carrying amount of mortgage loans as of the balance sheet date.

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Agriculture loans.

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