$WABC
Westamerica Bancorp Stock $wabc

$wabc Overview Financials Valuation SEC Filings Company Website

2020 Q2 Form 10-Q Financial Statement

#000117184320005542 Filed on August 05, 2020

Income Statement

Concept	2020 Q2	2019 Q2	2019 Q1
Revenue	$41.54M	$39.63M	$39.48M
YoY Change	4.83%	6.11%	8.72%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$6.100M	$5.100M	$4.800M
YoY Change	19.61%	-53.64%	200.0%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense	$435.0K	$487.0K	$494.0K
YoY Change	-10.68%	6.1%	7.63%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$25.90M	$25.87M	$25.39M
YoY Change	0.15%	12.88%	16.5%
Income Tax	$6.342M	$6.241M	$5.739M
% Of Pretax Income	24.48%	24.13%	22.61%
Net Earnings	$19.56M	$19.63M	$19.65M
YoY Change	-0.32%	8.97%	12.22%
Net Earnings / Revenue	47.09%	49.53%	49.76%
Basic Earnings Per Share	$0.72	$0.73	$0.73
Diluted Earnings Per Share	$0.72	$0.73	$0.73
COMMON SHARES
Basic Shares Outstanding	26.94M	26.94M	26.84M
Diluted Shares Outstanding	26.95M	26.99M	26.91M

Balance Sheet

Concept	2020 Q2	2019 Q2	2019 Q1
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$500.8M	$418.6M
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets
YoY Change
LONG-TERM ASSETS
Property, Plant & Equipment	$34.06M	$34.01M	$33.93M
YoY Change	0.14%	-4.92%	-5.19%
Goodwill	$121.7M	$121.7M	$121.7M
YoY Change	0.0%	0.0%	0.0%
Intangibles
YoY Change
Long-Term Investments	$14.20M	$14.20M	$14.20M
YoY Change	0.0%	0.0%	0.0%
Other Assets	$0.00	$15.40M	$27.30M
YoY Change	-100.0%	-66.3%	-36.21%
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$6.464B	$5.523B	$5.556B
YoY Change	17.03%	-0.98%	0.09%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses	$15.80M	$20.50M	$17.90M
YoY Change	-22.93%
Deferred Revenue
YoY Change
Short-Term Debt	$86.17M	$54.58M	$58.32M
YoY Change	57.88%	-20.78%	-10.77%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$15.80M	$20.50M	$17.90M
YoY Change	-22.93%	-70.25%	-72.63%
LONG-TERM LIABILITIES
Long-Term Debt	$0.00	$0.00	$0.00
YoY Change
Other Long-Term Liabilities	$67.70M	$24.70M	$30.40M
YoY Change	174.09%	-30.81%	-14.85%
Total Long-Term Liabilities	$67.70M	$24.70M	$30.40M
YoY Change	174.09%	-30.81%	-14.85%
TOTAL LIABILITIES
Total Short-Term Liabilities	$15.80M	$20.50M	$17.90M
Total Long-Term Liabilities	$67.70M	$24.70M	$30.40M
Total Liabilities	$5.656B	$4.830B	$4.899B
YoY Change	17.1%	-3.24%	-1.4%
SHAREHOLDERS EQUITY
Retained Earnings	$247.0M	$220.2M	$211.9M
YoY Change	12.17%	15.17%	15.07%
Common Stock	$467.4M	$459.4M	$455.3M
YoY Change	1.74%	3.62%	3.52%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$808.1M	$693.4M	$656.8M
YoY Change
Total Liabilities & Shareholders Equity	$6.464B	$5.523B	$5.556B
YoY Change	17.03%	-0.98%	0.09%

Cashflow Statement

Concept	2020 Q2	2019 Q2	2019 Q1
OPERATING ACTIVITIES
Net Income	$19.56M	$19.63M	$19.65M
YoY Change	-0.32%	8.97%	12.22%
Depreciation, Depletion And Amortization	$6.100M	$5.100M	$4.800M
YoY Change	19.61%	-53.64%	200.0%
Cash From Operating Activities	$11.40M	$16.10M	$23.44M
YoY Change	-29.19%	-31.2%	-11.48%
INVESTING ACTIVITIES
Capital Expenditures	$400.0K	-$1.000M	$393.0K
YoY Change	-140.0%	11.11%	-72.19%
Acquisitions
YoY Change
Other Investing Activities	-$507.0M	$56.80M	$50.60M
YoY Change	-992.61%	51.87%	-157.18%
Cash From Investing Activities	-$506.6M	$55.80M	$50.23M
YoY Change	-1007.89%	52.88%	-155.85%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net			$0.00
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	691.3M	-75.00M	-$72.16M
YoY Change	-1021.73%	-655.56%	-263.76%
NET CHANGE
Cash From Operating Activities	11.40M	16.10M	$23.44M
Cash From Investing Activities	-506.6M	55.80M	$50.23M
Cash From Financing Activities	691.3M	-75.00M	-$72.16M
Net Change In Cash	196.1M	-3.100M	$1.504M
YoY Change	-6425.81%	-104.22%	-107.75%
FREE CASH FLOW
Cash From Operating Activities	$11.40M	$16.10M	$23.44M
Capital Expenditures	$400.0K	-$1.000M	$393.0K
Free Cash Flow	$11.00M	$17.10M	$23.04M
YoY Change	-35.67%	-29.63%	-8.06%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2020Q3	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	26932929
CY2020Q2	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	16000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	656390000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	744296000	USD
CY2020Q2	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2019Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2020Q2	us-gaap	Common Stock No Par Value CommonStockNoParValue	0
CY2019Q4	us-gaap	Common Stock No Par Value CommonStockNoParValue	0
CY2019Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	150000000
CY2020Q2	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	150000000
CY2020Q2	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	26933000
CY2020Q2	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	26933000
CY2019Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	27062000
CY2019Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	27062000
CY2020Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.41
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.82
CY2019Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.41
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.81
CY2019Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	0	USD
CY2020Q2	wabc	High Risk Collateralized Mortgage Obligations HighRiskCollateralizedMortgageObligations	0	USD
CY2019Q4	wabc	High Risk Collateralized Mortgage Obligations HighRiskCollateralizedMortgageObligations	0	USD
	us-gaap	Other Than Temporary Impairment Loss Debt Securities Available For Sale OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSale	0	USD
CY2019Q4	wabc	Loans And Leases Receivable Nonaccrual Commitment To Lend LoansAndLeasesReceivableNonaccrualCommitmentToLend	0	USD
CY2020Q2	wabc	Troubled Debt Restructurings During Period TroubledDebtRestructuringsDuringPeriod	0	pure
	wabc	Troubled Debt Restructurings During Period TroubledDebtRestructuringsDuringPeriod	0	pure
CY2019Q2	wabc	Troubled Debt Restructurings During Period TroubledDebtRestructuringsDuringPeriod	0	pure
	wabc	Troubled Debt Restructurings During Period TroubledDebtRestructuringsDuringPeriod	0	pure
	us-gaap	Financing Receivables Impaired Troubled Debt Restructuring Write Down FinancingReceivablesImpairedTroubledDebtRestructuringWriteDown	0	USD
CY2019Q2	us-gaap	Financing Receivables Impaired Troubled Debt Restructuring Write Down FinancingReceivablesImpairedTroubledDebtRestructuringWriteDown	0	USD
	us-gaap	Financing Receivables Impaired Troubled Debt Restructuring Write Down FinancingReceivablesImpairedTroubledDebtRestructuringWriteDown	0	USD
CY2020Q2	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	0	pure
	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	0	pure
CY2019Q2	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	0	pure
CY2020Q2	us-gaap	Loans Receivable Held For Sale Amount LoansReceivableHeldForSaleAmount	0	USD
CY2019Q4	us-gaap	Loans Receivable Held For Sale Amount LoansReceivableHeldForSaleAmount	0	USD
CY2019Q4	us-gaap	Other Real Estate OtherRealEstate	43000	USD
CY2020Q2	wabc	Other Real Estate Reserve OtherRealEstateReserve	0	USD
CY2019Q4	wabc	Other Real Estate Reserve OtherRealEstateReserve	0	USD
CY2020Q2	us-gaap	Lessee Operating Lease Term Of Contract LesseeOperatingLeaseTermOfContract	P5Y
CY2020Q2	us-gaap	Lessee Operating Lease Renewal Term LesseeOperatingLeaseRenewalTerm	P5Y
CY2020Q2	us-gaap	Goodwill And Intangible Asset Impairment GoodwillAndIntangibleAssetImpairment	0	USD
	us-gaap	Goodwill And Intangible Asset Impairment GoodwillAndIntangibleAssetImpairment	0	USD
CY2019	us-gaap	Goodwill And Intangible Asset Impairment GoodwillAndIntangibleAssetImpairment	0	USD
	wabc	Amortization Expense Adjustment Resulting From A Change In Estimates Of Useful Lives Or Residual Values AmortizationExpenseAdjustmentResultingFromAChangeInEstimatesOfUsefulLivesOrResidualValues	0	USD
CY2019	wabc	Amortization Expense Adjustment Resulting From A Change In Estimates Of Useful Lives Or Residual Values AmortizationExpenseAdjustmentResultingFromAChangeInEstimatesOfUsefulLivesOrResidualValues	0	USD
CY2020Q2	us-gaap	Cash And Due From Banks CashAndDueFromBanks	500820000	USD
CY2019Q4	us-gaap	Cash And Due From Banks CashAndDueFromBanks	373421000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	3708370000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	3078846000	USD
CY2020Q2	wabc	Held To Maturity Securities Net HeldToMaturitySecuritiesNet	638281000	USD
CY2019Q4	wabc	Held To Maturity Securities Net HeldToMaturitySecuritiesNet	738072000	USD
CY2020Q2	wabc	Loans And Leases Receivable Gross Carrying Amount Covered And Noncovered LoansAndLeasesReceivableGrossCarryingAmountCoveredAndNoncovered	1316359000	USD
CY2019Q4	wabc	Loans And Leases Receivable Gross Carrying Amount Covered And Noncovered LoansAndLeasesReceivableGrossCarryingAmountCoveredAndNoncovered	1126664000	USD
CY2020Q2	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	24529000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	19484000	USD
CY2020Q2	us-gaap	Noninterest Bearing Deposit Liabilities Domestic NoninterestBearingDepositLiabilitiesDomestic	2702885000	USD
CY2020Q2	us-gaap	Loans And Leases Receivable Net Reported Amount Covered And Not Covered LoansAndLeasesReceivableNetReportedAmountCoveredAndNotCovered	1291830000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Net Reported Amount Covered And Not Covered LoansAndLeasesReceivableNetReportedAmountCoveredAndNotCovered	1107180000	USD
CY2020Q2	us-gaap	Other Real Estate And Foreclosed Assets OtherRealEstateAndForeclosedAssets	43000	USD
CY2019Q4	us-gaap	Other Real Estate And Foreclosed Assets OtherRealEstateAndForeclosedAssets	43000	USD
CY2020Q2	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	34061000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	34597000	USD
CY2020Q2	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	1245000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	1391000	USD
CY2020Q2	us-gaap	Goodwill Goodwill	121673000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	121673000	USD
CY2020Q2	us-gaap	Other Assets OtherAssets	167566000	USD
CY2019Q4	us-gaap	Other Assets OtherAssets	164332000	USD
CY2020Q2	us-gaap	Assets Assets	6463889000	USD
CY2019Q4	us-gaap	Assets Assets	5619555000	USD
CY2019Q4	us-gaap	Noninterest Bearing Deposit Liabilities Domestic NoninterestBearingDepositLiabilitiesDomestic	2240112000	USD
CY2020Q2	us-gaap	Interest Bearing Deposit Liabilities Domestic InterestBearingDepositLiabilitiesDomestic	2765527000	USD
CY2019Q4	us-gaap	Interest Bearing Deposit Liabilities Domestic InterestBearingDepositLiabilitiesDomestic	2572509000	USD
CY2020Q2	us-gaap	Deposits Deposits	5468412000	USD
CY2019Q4	us-gaap	Deposits Deposits	4812621000	USD
CY2020Q2	us-gaap	Short Term Borrowings ShortTermBorrowings	86170000	USD
CY2019Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	30928000	USD
CY2020Q2	us-gaap	Other Liabilities OtherLiabilities	101231000	USD
CY2019Q4	us-gaap	Other Liabilities OtherLiabilities	44589000	USD
CY2020Q2	us-gaap	Liabilities Liabilities	5655813000	USD
CY2019Q4	us-gaap	Liabilities Liabilities	4888138000	USD
CY2020Q2	us-gaap	Common Stock Value CommonStockValue	467351000	USD
CY2019Q4	us-gaap	Common Stock Value CommonStockValue	465460000	USD
CY2020Q2	wabc	Deferred Compensation DeferredCompensation	35000	USD
CY2019Q4	wabc	Deferred Compensation DeferredCompensation	771000	USD
CY2020Q2	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	93732000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	26051000	USD
CY2020Q2	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	246958000	USD
CY2019Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	239135000	USD
CY2020Q2	us-gaap	Stockholders Equity StockholdersEquity	808076000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	731417000	USD
CY2020Q2	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	6463889000	USD
CY2019Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	5619555000	USD
CY2020Q2	us-gaap	Interest And Fee Income Loans And Leases Held In Portfolio InterestAndFeeIncomeLoansAndLeasesHeldInPortfolio	15278000	USD
CY2019Q2	us-gaap	Interest And Fee Income Loans And Leases Held In Portfolio InterestAndFeeIncomeLoansAndLeasesHeldInPortfolio	14822000	USD
	us-gaap	Interest And Fee Income Loans And Leases Held In Portfolio InterestAndFeeIncomeLoansAndLeasesHeldInPortfolio	29087000	USD
	us-gaap	Interest And Fee Income Loans And Leases Held In Portfolio InterestAndFeeIncomeLoansAndLeasesHeldInPortfolio	29619000	USD
CY2020Q2	wabc	Interest And Dividend Income Equity Securities Operating InterestAndDividendIncomeEquitySecuritiesOperating	103000	USD
CY2019Q2	wabc	Interest And Dividend Income Equity Securities Operating InterestAndDividendIncomeEquitySecuritiesOperating	99000	USD
	wabc	Interest And Dividend Income Equity Securities Operating InterestAndDividendIncomeEquitySecuritiesOperating	206000	USD
	wabc	Interest And Dividend Income Equity Securities Operating InterestAndDividendIncomeEquitySecuritiesOperating	197000	USD
CY2020Q2	us-gaap	Interest Income Debt Securities Available For Sale Operating InterestIncomeDebtSecuritiesAvailableForSaleOperating	22429000	USD
CY2019Q2	us-gaap	Interest Income Debt Securities Available For Sale Operating InterestIncomeDebtSecuritiesAvailableForSaleOperating	17823000	USD
	us-gaap	Interest Income Debt Securities Available For Sale Operating InterestIncomeDebtSecuritiesAvailableForSaleOperating	43744000	USD
	us-gaap	Interest Income Debt Securities Available For Sale Operating InterestIncomeDebtSecuritiesAvailableForSaleOperating	35344000	USD
CY2020Q2	us-gaap	Interest And Dividend Income Securities Held To Maturity InterestAndDividendIncomeSecuritiesHeldToMaturity	3616000	USD
CY2019Q2	us-gaap	Interest And Dividend Income Securities Held To Maturity InterestAndDividendIncomeSecuritiesHeldToMaturity	4924000	USD
	us-gaap	Interest And Dividend Income Securities Held To Maturity InterestAndDividendIncomeSecuritiesHeldToMaturity	7524000	USD
	us-gaap	Interest And Dividend Income Securities Held To Maturity InterestAndDividendIncomeSecuritiesHeldToMaturity	10253000	USD
CY2020Q2	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	113000	USD
CY2019Q2	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	1958000	USD
	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	969000	USD
	us-gaap	Interest Income Deposits With Financial Institutions InterestIncomeDepositsWithFinancialInstitutions	3696000	USD
CY2020Q2	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	41539000	USD
CY2019Q2	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	39626000	USD
	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	81530000	USD
	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	79109000	USD
CY2020Q2	us-gaap	Interest Expense Deposits InterestExpenseDeposits	424000	USD
CY2019Q2	us-gaap	Interest Expense Deposits InterestExpenseDeposits	478000	USD
	us-gaap	Interest Expense Deposits InterestExpenseDeposits	858000	USD
	us-gaap	Interest Expense Deposits InterestExpenseDeposits	963000	USD
CY2020Q2	us-gaap	Interest Expense Short Term Borrowings InterestExpenseShortTermBorrowings	10000	USD
CY2019Q2	us-gaap	Interest Expense Short Term Borrowings InterestExpenseShortTermBorrowings	9000	USD
	us-gaap	Interest Expense Short Term Borrowings InterestExpenseShortTermBorrowings	18000	USD
	us-gaap	Interest Expense Short Term Borrowings InterestExpenseShortTermBorrowings	18000	USD
CY2020Q2	us-gaap	Interest Expense Other InterestExpenseOther	1000	USD
CY2019Q2	us-gaap	Interest Expense Other InterestExpenseOther	0	USD
	us-gaap	Interest Expense Other InterestExpenseOther	1000	USD
	us-gaap	Interest Expense Other InterestExpenseOther	0	USD
CY2020Q2	us-gaap	Interest Expense InterestExpense	435000	USD
CY2019Q2	us-gaap	Interest Expense InterestExpense	487000	USD
	us-gaap	Interest Expense InterestExpense	877000	USD
	us-gaap	Interest Expense InterestExpense	981000	USD
CY2020Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	41104000	USD
CY2019Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	39139000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	80653000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	78128000	USD
CY2020Q2	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	0	USD
CY2019Q2	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	0	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	4300000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	0	USD
CY2020Q2	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	41104000	USD
CY2019Q2	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	39139000	USD
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	76353000	USD
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	78128000	USD
CY2020Q2	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	71000	USD
CY2019Q2	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	26000	USD
	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	71000	USD
	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	50000	USD
CY2020Q2	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	0	USD
CY2019Q2	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	433000	USD
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	0	USD
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	433000	USD
CY2020Q2	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	821000	USD
CY2019Q2	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	889000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	2408000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	1847000	USD
CY2020Q2	us-gaap	Noninterest Income NoninterestIncome	9554000	USD
CY2019Q2	us-gaap	Noninterest Income NoninterestIncome	12288000	USD
	us-gaap	Noninterest Income NoninterestIncome	21202000	USD
	us-gaap	Noninterest Income NoninterestIncome	23867000	USD
CY2020Q2	us-gaap	Labor And Related Expense LaborAndRelatedExpense	12900000	USD
CY2019Q2	us-gaap	Labor And Related Expense LaborAndRelatedExpense	13090000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	25918000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	26198000	USD
CY2020Q2	us-gaap	Occupancy Net OccupancyNet	4791000	USD
CY2019Q2	us-gaap	Occupancy Net OccupancyNet	4916000	USD
	us-gaap	Occupancy Net OccupancyNet	9723000	USD
	us-gaap	Occupancy Net OccupancyNet	9964000	USD
CY2020Q2	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	2324000	USD
CY2019Q2	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	2367000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	4729000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	4736000	USD
CY2020Q2	us-gaap	Professional Fees ProfessionalFees	643000	USD
CY2019Q2	us-gaap	Professional Fees ProfessionalFees	481000	USD
	us-gaap	Professional Fees ProfessionalFees	1032000	USD
	us-gaap	Professional Fees ProfessionalFees	1146000	USD
CY2020Q2	wabc	Contract Courier Expense ContractCourierExpense	508000	USD
CY2019Q2	wabc	Contract Courier Expense ContractCourierExpense	451000	USD
	wabc	Contract Courier Expense ContractCourierExpense	999000	USD
	wabc	Contract Courier Expense ContractCourierExpense	893000	USD
CY2020Q2	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	73000	USD
CY2019Q2	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	79000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	146000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	389000	USD
CY2020Q2	wabc	Noninterest Expense Loss Contingency NoninterestExpenseLossContingency	0	USD
CY2019Q2	wabc	Noninterest Expense Loss Contingency NoninterestExpenseLossContingency	553000	USD
	wabc	Noninterest Expense Loss Contingency NoninterestExpenseLossContingency	0	USD
	wabc	Noninterest Expense Loss Contingency NoninterestExpenseLossContingency	553000	USD
CY2020Q2	us-gaap	Other Noninterest Expense OtherNoninterestExpense	3515000	USD
CY2019Q2	us-gaap	Other Noninterest Expense OtherNoninterestExpense	3624000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	6871000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	6865000	USD
CY2020Q2	us-gaap	Noninterest Expense NoninterestExpense	24754000	USD
CY2019Q2	us-gaap	Noninterest Expense NoninterestExpense	25561000	USD
	us-gaap	Noninterest Expense NoninterestExpense	49418000	USD
	us-gaap	Noninterest Expense NoninterestExpense	50744000	USD
CY2020Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	25904000	USD
CY2019Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	25866000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	48137000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	51251000	USD
CY2020Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	6342000	USD
CY2019Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	6241000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	11613000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	11980000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	19562000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	19625000	USD
	us-gaap	Net Income Loss NetIncomeLoss	36524000	USD
	us-gaap	Net Income Loss NetIncomeLoss	39271000	USD
CY2020Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	26935000
CY2019Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	26942000
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	27001000
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	26892000
CY2020Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	26951000
CY2019Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	26987000
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	27024000
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	26950000
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.72
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.73
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.35
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.46
CY2020Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.72
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.73
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.35
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.46
CY2020Q2	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.41
CY2019Q2	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.41
	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.82
	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.81
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	19562000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	19625000	USD
	us-gaap	Net Income Loss NetIncomeLoss	36524000	USD
	us-gaap	Net Income Loss NetIncomeLoss	39271000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	132902000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	34602000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	96158000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	75415000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	39291000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	10229000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	28427000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	22295000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	-0	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	71000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	-0	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	71000	USD
CY2020Q2	us-gaap	Stockholders Equity StockholdersEquity	808076000	USD
CY2019Q1	us-gaap	Stockholders Equity StockholdersEquity	656767000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	615591000	USD
	us-gaap	Net Income Loss NetIncomeLoss	39271000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	19625000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	24373000	USD
CY2019Q2	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	2539000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	53120000	USD
	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	8310000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	21000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	0	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	21000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	0	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	93561000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	24373000	USD
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	67681000	USD
	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	53120000	USD
CY2020Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	113123000	USD
CY2019Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	43998000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	104205000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	92391000	USD
CY2020Q1	us-gaap	Stockholders Equity StockholdersEquity	705546000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	19562000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	93561000	USD
CY2020Q2	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	572000	USD
CY2020Q2	us-gaap	Stock Issued During Period Value Share Based Compensation Gross StockIssuedDuringPeriodValueShareBasedCompensationGross	525000	USD
CY2020Q2	us-gaap	Stock Granted During Period Value Sharebased Compensation StockGrantedDuringPeriodValueSharebasedCompensation	45000	USD
CY2020Q2	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	619000	USD
CY2020Q2	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	11116000	USD
CY2020Q2	us-gaap	Stockholders Equity StockholdersEquity	808076000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	731417000	USD
	us-gaap	Net Income Loss NetIncomeLoss	36524000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	67681000	USD
	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	2838000	USD
	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	534000	USD
	us-gaap	Stock Issued During Period Value Share Based Compensation Gross StockIssuedDuringPeriodValueShareBasedCompensationGross	1050000	USD
	us-gaap	Stock Granted During Period Value Sharebased Compensation StockGrantedDuringPeriodValueSharebasedCompensation	66000	USD
	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	9866000	USD
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	22220000	USD
CY2019Q2	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	1073000	USD
CY2019Q2	us-gaap	Stock Issued During Period Value Share Based Compensation Gross StockIssuedDuringPeriodValueShareBasedCompensationGross	541000	USD
CY2019Q2	us-gaap	Stock Granted During Period Value Sharebased Compensation StockGrantedDuringPeriodValueSharebasedCompensation	48000	USD
CY2019Q2	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	488000	USD
CY2019Q2	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	11041000	USD
CY2019Q2	us-gaap	Stockholders Equity StockholdersEquity	693437000	USD
	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	1073000	USD
	us-gaap	Stock Issued During Period Value Share Based Compensation Gross StockIssuedDuringPeriodValueShareBasedCompensationGross	1082000	USD
	us-gaap	Stock Granted During Period Value Sharebased Compensation StockGrantedDuringPeriodValueSharebasedCompensation	65000	USD
	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	488000	USD
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	21786000	USD
CY2019Q2	us-gaap	Stockholders Equity StockholdersEquity	693437000	USD
	us-gaap	Net Income Loss NetIncomeLoss	36524000	USD
	us-gaap	Net Income Loss NetIncomeLoss	39271000	USD
	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	12361000	USD
	us-gaap	Stock Option Plan Expense StockOptionPlanExpense	1050000	USD
	us-gaap	Stock Option Plan Expense StockOptionPlanExpense	1082000	USD
	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	71000	USD
	us-gaap	Equity Securities Fv Ni Gain Loss EquitySecuritiesFvNiGainLoss	50000	USD
	us-gaap	Depreciation Amortization And Accretion Net DepreciationAmortizationAndAccretionNet	9852000	USD
	wabc	Reversal Of Provision For Loan And Lease Losses ReversalOfProvisionForLoanAndLeaseLosses	-4300000	USD
	wabc	Reversal Of Provision For Loan And Lease Losses ReversalOfProvisionForLoanAndLeaseLosses	-0	USD
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	-0	USD
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	433000	USD
	us-gaap	Amortization Of Deferred Loan Origination Fees Net AmortizationOfDeferredLoanOriginationFeesNet	1057000	USD
	us-gaap	Amortization Of Deferred Loan Origination Fees Net AmortizationOfDeferredLoanOriginationFeesNet	215000	USD
	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	3526000	USD
	us-gaap	Increase Decrease In Accrued Interest Receivable Net IncreaseDecreaseInAccruedInterestReceivableNet	673000	USD
	us-gaap	Increase Decrease In Income Taxes Receivable IncreaseDecreaseInIncomeTaxesReceivable	-0	USD
	us-gaap	Increase Decrease In Income Taxes Receivable IncreaseDecreaseInIncomeTaxesReceivable	6549000	USD
	us-gaap	Increase Decrease In Income Taxes IncreaseDecreaseInIncomeTaxes	-585000	USD
	us-gaap	Increase Decrease In Income Taxes IncreaseDecreaseInIncomeTaxes	0	USD
	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	-478000	USD
	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	-4902000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	12478000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	20013000	USD
	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	52000	USD
	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	44000	USD
	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	28875000	USD
	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	12323000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	65923000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	39541000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	189704000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	-44721000	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	0	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	869942000	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	1273000	USD
	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	418223000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	343170000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	368216000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	97555000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	111099000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1389000	USD
	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	1425000	USD
	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	0	USD
	us-gaap	Proceeds From Sale Of Foreclosed Assets ProceedsFromSaleOfForeclosedAssets	307000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-620310000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	105968000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	655791000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	-136577000	USD
	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	55243000	USD
	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	3334000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	2838000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	8310000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	9866000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	488000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	22220000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	21786000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	681786000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-147207000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	127399000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-1698000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	373421000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	420284000	USD
CY2020Q2	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	500820000	USD
CY2019Q2	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations	418586000	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	1639000	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	23087000	USD
	wabc	Right Of Use Asset Obtained In Exchange For Operating Lease Liability Amount Recognized Upon Adoption Of Asu201602 RightOfUseAssetObtainedInExchangeForOperatingLeaseLiabilityAmountRecognizedUponAdoptionOfASU201602	0	USD
	wabc	Right Of Use Asset Obtained In Exchange For Operating Lease Liability Amount Recognized Upon Adoption Of Asu201602 RightOfUseAssetObtainedInExchangeForOperatingLeaseLiabilityAmountRecognizedUponAdoptionOfASU201602	15325000	USD
	us-gaap	Other Significant Noncash Transaction Value Of Consideration Given1 OtherSignificantNoncashTransactionValueOfConsiderationGiven1	13632000	USD
	us-gaap	Other Significant Noncash Transaction Value Of Consideration Given1 OtherSignificantNoncashTransactionValueOfConsiderationGiven1	0	USD
	us-gaap	Operating Lease Payments OperatingLeasePayments	3276000	USD
	us-gaap	Operating Lease Payments OperatingLeasePayments	3411000	USD
	us-gaap	Interest Paid Net InterestPaidNet	825000	USD
	us-gaap	Interest Paid Net InterestPaidNet	874000	USD
	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	11900000	USD
	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	12910000	USD
CY2020Q1	wabc	Allowance For Credit Losses For Unfunded Commitments AllowanceForCreditLossesForUnfundedCommitments	19484000	USD
CY2020Q1	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	0	USD
CY2020Q1	wabc	Reserve For Unfunded Commitments ReserveForUnfundedCommitments	2160000	USD
CY2020Q2	wabc	Lessee Operating Lease Liability To Be Paid After Year Four LesseeOperatingLeaseLiabilityToBePaidAfterYearFour	708000	USD
CY2019Q2	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	1797000	USD
	us-gaap	Unrealized Gain Loss On Securities UnrealizedGainLossOnSecurities	50000	USD
CY2020Q2	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	0	USD
CY2020Q2	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	3575297000	USD
CY2020Q2	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	134488000	USD
CY2020Q2	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	1415000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	3708370000	USD
CY2020Q2	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	638297000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	18138000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	45000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	656390000	USD
CY2020Q2	wabc	Debt Securities Availableforsale And Heldtomaturity Amortized Cost DebtSecuritiesAvailableforsaleAndHeldtomaturityAmortizedCost	4213594000	USD
CY2020Q2	wabc	Debt Securities Gross Unrecognized Gains DebtSecuritiesGrossUnrecognizedGains	152626000	USD
CY2020Q2	wabc	Debt Securities Gross Unrecognized Losses DebtSecuritiesGrossUnrecognizedLosses	1460000	USD
CY2020Q2	us-gaap	Debt Securities Available For Sale And Held To Maturity DebtSecuritiesAvailableForSaleAndHeldToMaturity	4364760000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	3041860000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	43857000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	6871000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	3078846000	USD
CY2019Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	738072000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	8460000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	2236000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	744296000	USD
CY2019Q4	wabc	Debt Securities Availableforsale And Heldtomaturity Amortized Cost DebtSecuritiesAvailableforsaleAndHeldtomaturityAmortizedCost	3779932000	USD
CY2019Q4	wabc	Debt Securities Gross Unrecognized Gains DebtSecuritiesGrossUnrecognizedGains	52317000	USD
CY2019Q4	wabc	Debt Securities Gross Unrecognized Losses DebtSecuritiesGrossUnrecognizedLosses	9107000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale And Held To Maturity DebtSecuritiesAvailableForSaleAndHeldToMaturity	3823142000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	528253000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	529421000	USD
CY2020Q2	us-gaap	Heldtomaturity Securities Debt Maturities Next Rolling Twelve Months Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCost	57015000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Fair Value HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue	57392000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	1062469000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	1116754000	USD
CY2020Q2	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Two Through Five Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCost	146003000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	149824000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	1142837000	USD
CY2020Q2	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCost	128728000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	1190058000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	133290000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	26769000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	28423000	USD
CY2020Q2	us-gaap	Heldtomaturity Securities Debt Maturities Rolling After Ten Years Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingAfterTenYearsAmortizedCost	0	USD
CY2020Q2	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue	0	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	2760328000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate	2864656000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Debt Maturities Single Maturity Date Amortized Cost Basis HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	331746000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Debt Maturities Single Maturity Date Fair Value HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValue	340506000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost	814969000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	843714000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Debt Maturities Without Single Maturity Date Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesWithoutSingleMaturityDateNetCarryingAmount	306551000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Debt Maturities Without Single Maturity Date Fair Value HeldToMaturitySecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	315884000	USD
CY2020Q2	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	3575297000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	3708370000	USD
CY2020Q2	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	638297000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	656390000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	294698000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	295255000	USD
CY2019Q4	us-gaap	Heldtomaturity Securities Debt Maturities Next Rolling Twelve Months Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesNextRollingTwelveMonthsAmortizedCost	70378000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Fair Value HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue	70602000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	1104775000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	1122391000	USD
CY2019Q4	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Two Through Five Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearTwoThroughFiveAmortizedCost	161911000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	165126000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	670595000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	683277000	USD
CY2019Q4	us-gaap	Heldtomaturity Securities Debt Maturities Rolling Year Six Through Ten Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingYearSixThroughTenAmortizedCost	149492000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Debt Maturities After Five Through Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	153724000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	33489000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	34465000	USD
CY2019Q4	us-gaap	Heldtomaturity Securities Debt Maturities Rolling After Ten Years Amortized Cost HeldtomaturitySecuritiesDebtMaturitiesRollingAfterTenYearsAmortizedCost	0	USD
CY2019Q4	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue	0	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	2103557000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate	2135388000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Debt Maturities Single Maturity Date Amortized Cost Basis HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	381781000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Debt Maturities Single Maturity Date Fair Value HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValue	389452000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost	938303000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	943458000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Debt Maturities Without Single Maturity Date Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesWithoutSingleMaturityDateNetCarryingAmount	356291000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Debt Maturities Without Single Maturity Date Fair Value HeldToMaturitySecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	354844000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	3041860000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	3078846000	USD
CY2019Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	738072000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	744296000	USD
CY2020Q2	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Number Of Positions DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions	16	pure
CY2020Q2	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	226864000	USD
CY2020Q2	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	1015000	USD
CY2020Q2	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Number Of Positions DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions	8	pure
CY2020Q2	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	22915000	USD
CY2020Q2	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	400000	USD
CY2020Q2	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Number Of Positions DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions	24	pure
CY2020Q2	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	249779000	USD
CY2020Q2	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	1415000	USD
CY2020Q2	wabc	Heldtomaturity Securities Less Than12 Months Number Of Positions HeldtomaturitySecuritiesLessThan12MonthsNumberOfPositions	4	pure
CY2020Q2	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	686000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	-0	USD
CY2020Q2	wabc	Heldtomaturity Securities12 Months Or Longer Number Of Positions HeldtomaturitySecurities12MonthsOrLongerNumberOfPositions	4	pure
CY2020Q2	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	1883000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	45000	USD
CY2020Q2	wabc	Heldtomaturity Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions1 HeldtomaturitySecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1	8	pure
CY2020Q2	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue	2569000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	45000	USD
CY2020Q2	us-gaap	Pledged Financial Instruments Not Separately Reported Securities Pledged PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesPledged	868665000	USD
CY2019Q4	us-gaap	Pledged Financial Instruments Not Separately Reported Securities Pledged PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesPledged	760365000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Number Of Positions DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions	16	pure
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	96910000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	314000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Number Of Positions DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions	70	pure
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	462348000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	6557000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Number Of Positions DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions	86	pure
CY2019Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	559258000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	6871000	USD
CY2019Q4	wabc	Heldtomaturity Securities Less Than12 Months Number Of Positions HeldtomaturitySecuritiesLessThan12MonthsNumberOfPositions	6	pure
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	12098000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	87000	USD
CY2019Q4	wabc	Heldtomaturity Securities12 Months Or Longer Number Of Positions HeldtomaturitySecurities12MonthsOrLongerNumberOfPositions	55	pure
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	277454000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	2149000	USD
CY2019Q4	wabc	Heldtomaturity Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions1 HeldtomaturitySecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1	61	pure
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue	289552000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	2236000	USD
CY2019Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	0	USD
	wabc	Debt Securities Heldtomaturity Allowance For Credit Loss Increase Decrease From Adoption Of Accounting Policies DebtSecuritiesHeldtomaturityAllowanceForCreditLossIncreaseDecreaseFromAdoptionOfAccountingPolicies	16000	USD
	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	0	USD
	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Writeoff DebtSecuritiesHeldToMaturityAllowanceForCreditLossWriteoff	0	USD
	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Recovery DebtSecuritiesHeldToMaturityAllowanceForCreditLossRecovery	0	USD
CY2020Q2	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	638297000	USD
CY2020Q2	us-gaap	Debt Securities Held To Maturity Nonaccrual DebtSecuritiesHeldToMaturityNonaccrual	0	USD
CY2020Q2	us-gaap	Interest Income Securities Taxable InterestIncomeSecuritiesTaxable	22920000	USD
CY2019Q2	us-gaap	Interest Income Securities Taxable InterestIncomeSecuritiesTaxable	18773000	USD
	us-gaap	Interest Income Securities Taxable InterestIncomeSecuritiesTaxable	44884000	USD
	us-gaap	Interest Income Securities Taxable InterestIncomeSecuritiesTaxable	37406000	USD
CY2020Q2	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	3228000	USD
CY2019Q2	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	4073000	USD
	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	6590000	USD
	us-gaap	Interest Income Securities Tax Exempt InterestIncomeSecuritiesTaxExempt	8388000	USD
CY2020Q2	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	26148000	USD
CY2019Q2	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	22846000	USD
	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	51474000	USD
	us-gaap	Interest And Dividend Income Securities InterestAndDividendIncomeSecurities	45794000	USD
CY2020Q2	wabc	Loans And Leases Receivable Gross Carrying Amount Covered And Noncovered LoansAndLeasesReceivableGrossCarryingAmountCoveredAndNoncovered	1316359000	USD
CY2019Q4	wabc	Loans And Leases Receivable Gross Carrying Amount Covered And Noncovered LoansAndLeasesReceivableGrossCarryingAmountCoveredAndNoncovered	1126664000	USD
CY2020Q1	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	24804000	USD
CY2020Q2	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	0	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	804000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	529000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	24529000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	19484000	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	4300000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	2377000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	1105000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	24529000	USD
CY2019Q1	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	20477000	USD
CY2019Q2	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	0	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	973000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	613000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	20117000	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	21351000	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	0	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	2364000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	1130000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	20117000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	2413000	USD
CY2020Q2	wabc	Loans And Leases Receivable Gross Carrying Amount Covered And Noncovered LoansAndLeasesReceivableGrossCarryingAmountCoveredAndNoncovered	1316359000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	17071000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	19484000	USD
CY2019Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	15824000	USD
CY2019Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	1110840000	USD
CY2019Q4	wabc	Loans And Leases Receivable Gross Carrying Amount Covered And Noncovered LoansAndLeasesReceivableGrossCarryingAmountCoveredAndNoncovered	1126664000	USD
CY2020Q2	wabc	Loans And Leases Receivable Gross Carrying Amount Covered And Noncovered LoansAndLeasesReceivableGrossCarryingAmountCoveredAndNoncovered	1316359000	USD
CY2019Q4	wabc	Loans And Leases Receivable Gross Carrying Amount Covered And Noncovered LoansAndLeasesReceivableGrossCarryingAmountCoveredAndNoncovered	1126664000	USD
CY2020Q2	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	1304707000	USD
CY2020Q2	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	4233000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	1114951000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	4440000	USD
CY2019Q4	wabc	Loans And Leases Receivable Gross Carrying Amount Covered And Noncovered LoansAndLeasesReceivableGrossCarryingAmountCoveredAndNoncovered	1126664000	USD
CY2020Q2	wabc	Loans And Leases Receivable Nonaccrual Commitment To Lend LoansAndLeasesReceivableNonaccrualCommitmentToLend	0	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	7662000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance	9140000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	8160000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance	8160000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	2413000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	15822000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Unpaid Principal Balance ImpairedFinancingReceivableUnpaidPrincipalBalance	17300000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	2413000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	16474000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	294000	USD
	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	16773000	USD
	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	611000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	7	pure
	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	8608000	USD
CY2020Q2	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	6324000	USD
CY2019	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	8886000	USD
CY2020Q2	wabc	Financing Receivable Modifications Period End Impairment Allowance FinancingReceivableModificationsPeriodEndImpairmentAllowance	0	USD
CY2019	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	9	pure
CY2020Q2	wabc	Lihtc Investments LIHTCInvestments	19535000	USD
CY2019Q4	us-gaap	Financing Receivable Modifications Recorded Investment FinancingReceivableModificationsRecordedInvestment	6713000	USD
CY2019Q4	wabc	Financing Receivable Modifications Period End Impairment Allowance FinancingReceivableModificationsPeriodEndImpairmentAllowance	11000	USD
CY2020Q2	us-gaap	Financing Receivables Impaired Troubled Debt Restructuring Write Down FinancingReceivablesImpairedTroubledDebtRestructuringWriteDown	0	USD
	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	0	pure
CY2020Q2	us-gaap	Other Real Estate OtherRealEstate	43000	USD
CY2020Q2	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	283000	USD
CY2019Q4	us-gaap	Mortgage Loans In Process Of Foreclosure Amount MortgageLoansInProcessOfForeclosureAmount	124000	USD
CY2020Q2	wabc	Unsecured Loan Limit Percentage Of Shareholders Equity California Financial Code UnsecuredLoanLimitPercentageOfShareholdersEquityCaliforniaFinancialCode	0.15	pure
CY2020Q2	wabc	Secured And Unsecured Loan Limit Percentage California Financial Code SecuredAndUnsecuredLoanLimitPercentageCaliforniaFinancialCode	0.25	pure
CY2020Q2	wabc	Loan Commitments And Standby Letters Of Credit Related To Real Estate Loans LoanCommitmentsAndStandbyLettersOfCreditRelatedToRealEstateLoans	40267000	USD
CY2019Q4	wabc	Loan Commitments And Standby Letters Of Credit Related To Real Estate Loans LoanCommitmentsAndStandbyLettersOfCreditRelatedToRealEstateLoans	43129000	USD
CY2020Q2	us-gaap	Federal Reserve Bank Stock FederalReserveBankStock	14069000	USD
CY2019Q4	us-gaap	Federal Reserve Bank Stock FederalReserveBankStock	14069000	USD
CY2020Q2	us-gaap	Other Investments And Securities At Cost OtherInvestmentsAndSecuritiesAtCost	158000	USD
CY2019Q4	us-gaap	Other Investments And Securities At Cost OtherInvestmentsAndSecuritiesAtCost	158000	USD
CY2020Q2	us-gaap	Cost Method Investments CostMethodInvestments	14227000	USD
CY2019Q4	us-gaap	Cost Method Investments CostMethodInvestments	14227000	USD
CY2020Q2	us-gaap	Bank Owned Life Insurance BankOwnedLifeInsurance	59182000	USD
CY2019Q4	us-gaap	Bank Owned Life Insurance BankOwnedLifeInsurance	57810000	USD
CY2020Q2	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	0	USD
CY2019Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	11085000	USD
CY2020Q2	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	15757000	USD
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	17136000	USD
CY2020Q2	wabc	Lihtc Investments LIHTCInvestments	19535000	USD
CY2019Q4	wabc	Lihtc Investments LIHTCInvestments	20773000	USD
CY2020Q2	us-gaap	Interest Receivable Current InterestReceivableCurrent	32322000	USD
CY2019Q4	us-gaap	Interest Receivable Current InterestReceivableCurrent	28797000	USD
CY2020Q2	us-gaap	Prepaid Expense Current And Noncurrent PrepaidExpenseCurrentAndNoncurrent	4140000	USD
CY2019Q4	us-gaap	Prepaid Expense Current And Noncurrent PrepaidExpenseCurrentAndNoncurrent	3737000	USD
CY2020Q2	us-gaap	Other Assets Miscellaneous OtherAssetsMiscellaneous	22403000	USD
CY2019Q4	us-gaap	Other Assets Miscellaneous OtherAssetsMiscellaneous	10767000	USD
CY2020Q2	us-gaap	Other Assets OtherAssets	167566000	USD
CY2019Q4	us-gaap	Other Assets OtherAssets	164332000	USD
CY2020Q2	us-gaap	Qualified Affordable Housing Project Investments Commitment QualifiedAffordableHousingProjectInvestmentsCommitment	15054000	USD
CY2019Q4	wabc	Lihtc Investments LIHTCInvestments	20773000	USD
CY2019Q4	us-gaap	Qualified Affordable Housing Project Investments Commitment QualifiedAffordableHousingProjectInvestmentsCommitment	16231000	USD
CY2020Q2	us-gaap	Qualified Affordable Housing Project Investments Commitment QualifiedAffordableHousingProjectInvestmentsCommitment	15054000	USD
CY2020Q2	us-gaap	Income Loss From Affordable Housing Projects Equity Method Investments IncomeLossFromAffordableHousingProjectsEquityMethodInvestments	600000	USD
CY2019Q2	us-gaap	Income Loss From Affordable Housing Projects Equity Method Investments IncomeLossFromAffordableHousingProjectsEquityMethodInvestments	600000	USD
	us-gaap	Income Loss From Affordable Housing Projects Equity Method Investments IncomeLossFromAffordableHousingProjectsEquityMethodInvestments	1200000	USD
	us-gaap	Income Loss From Affordable Housing Projects Equity Method Investments IncomeLossFromAffordableHousingProjectsEquityMethodInvestments	1200000	USD
CY2020Q2	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	225000	USD
CY2019Q2	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	225000	USD
	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	450000	USD
	us-gaap	Affordable Housing Tax Credits And Other Tax Benefits Amount AffordableHousingTaxCreditsAndOtherTaxBenefitsAmount	450000	USD
CY2020Q2	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	17821000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	0	USD
CY2020Q2	us-gaap	Operating Lease Liability OperatingLeaseLiability	15757000	USD
CY2019Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	17136000	USD
CY2020Q2	wabc	Securities Purchase Pending Settlement Liability SecuritiesPurchasePendingSettlementLiability	13632000	USD
CY2019Q4	wabc	Securities Purchase Pending Settlement Liability SecuritiesPurchasePendingSettlementLiability	0	USD
CY2020Q2	us-gaap	Other Sundry Liabilities OtherSundryLiabilities	54021000	USD
CY2019Q4	us-gaap	Other Sundry Liabilities OtherSundryLiabilities	27453000	USD
CY2020Q2	us-gaap	Other Liabilities OtherLiabilities	101231000	USD
CY2019Q4	us-gaap	Other Liabilities OtherLiabilities	44589000	USD
CY2020Q2	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	17821000	USD
	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	21789000	USD
CY2020Q2	us-gaap	Deferred Tax Liabilities Investments DeferredTaxLiabilitiesInvestments	39341000	USD
	us-gaap	Debt Securities Available For Sale Unrealized Gain Loss DebtSecuritiesAvailableForSaleUnrealizedGainLoss	133073000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	11085000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Unrealized Losses On Availablefor Sale Securities Gross DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross	10934000	USD
CY2020Q2	us-gaap	Operating Lease Liability OperatingLeaseLiability	15757000	USD
CY2020Q2	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	15757000	USD
CY2020Q2	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P3Y9M18D
CY2020Q2	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0280	pure
CY2020Q2	us-gaap	Operating Lease Cost OperatingLeaseCost	1657000	USD
	us-gaap	Operating Lease Cost OperatingLeaseCost	3317000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	3703000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	4645000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Remainder Of Fiscal Year LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear	3046000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	2980000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	1565000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	16647000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	890000	USD
CY2020Q2	us-gaap	Operating Lease Liability OperatingLeaseLiability	15757000	USD
CY2020Q2	wabc	Amortization Expense Adjustment Resulting From A Change In Estimates Of Useful Lives Or Residual Values AmortizationExpenseAdjustmentResultingFromAChangeInEstimatesOfUsefulLivesOrResidualValues	0	USD
CY2020Q2	us-gaap	Goodwill Goodwill	121673000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	121673000	USD
CY2020Q2	us-gaap	Noninterest Bearing Deposit Liabilities Domestic NoninterestBearingDepositLiabilitiesDomestic	2702885000	USD
CY2019Q4	us-gaap	Noninterest Bearing Deposit Liabilities Domestic NoninterestBearingDepositLiabilitiesDomestic	2240112000	USD
CY2020Q2	us-gaap	Demand Deposit Accounts DemandDepositAccounts	997593000	USD
CY2019Q4	us-gaap	Demand Deposit Accounts DemandDepositAccounts	931888000	USD
CY2020Q2	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	1605169000	USD
CY2019Q4	us-gaap	Deposits Savings Deposits DepositsSavingsDeposits	1471284000	USD
CY2020Q2	us-gaap	Time Deposits Less Than100000 TimeDepositsLessThan100000	84717000	USD
CY2019Q4	us-gaap	Time Deposits Less Than100000 TimeDepositsLessThan100000	88355000	USD
CY2020Q2	wabc	Time Deposits100 Thousand Through250 Thousand TimeDeposits100ThousandThrough250Thousand	52084000	USD
CY2019Q4	wabc	Time Deposits100 Thousand Through250 Thousand TimeDeposits100ThousandThrough250Thousand	54874000	USD
CY2020Q2	wabc	Time Deposits More Than250 Thousand TimeDepositsMoreThan250Thousand	25964000	USD
CY2019Q4	wabc	Time Deposits More Than250 Thousand TimeDepositsMoreThan250Thousand	26108000	USD
CY2020Q2	us-gaap	Deposits Deposits	5468412000	USD
CY2019Q4	us-gaap	Deposits Deposits	4812621000	USD
CY2020Q2	wabc	Demand Deposit Overdrafts DemandDepositOverdrafts	1517000	USD
CY2019Q4	wabc	Demand Deposit Overdrafts DemandDepositOverdrafts	1055000	USD
CY2020Q2	us-gaap	Interest Expense Time Deposits100000 Or More InterestExpenseTimeDeposits100000OrMore	79000	USD
	us-gaap	Interest Expense Time Deposits100000 Or More InterestExpenseTimeDeposits100000OrMore	158000	USD
CY2019Q2	us-gaap	Interest Expense Time Deposits100000 Or More InterestExpenseTimeDeposits100000OrMore	82000	USD
	us-gaap	Interest Expense Time Deposits100000 Or More InterestExpenseTimeDeposits100000OrMore	164000	USD
CY2020Q2	us-gaap	Guarantee Obligations Current Carrying Value GuaranteeObligationsCurrentCarryingValue	580000	USD
	us-gaap	Schedule Of Repurchase Agreements ScheduleOfRepurchaseAgreements	<table border="0" cellpadding="0" cellspacing="0" class="finTable" style="margin-right: 15%; width: 85%; font-size: 10pt; font-family: "Times New Roman", Times, serif; text-indent: 0px;"><tbody><tr style="vertical-align: bottom;"><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td colspan="6" style="text-align: center; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt; border-bottom: 1px solid rgb(0, 0, 0);"> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:center;">Repurchase Agreements (Sweep)<br/> Accounted for as Secured Borrowings</p> </td><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt; border-bottom: 1px solid rgb(0, 0, 0);"> </td></tr> <tr style="vertical-align: bottom;"><td style="border-bottom: 1px none rgb(0, 0, 0); font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="border-bottom: 1px none rgb(0, 0, 0); font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td colspan="6" style="border-bottom: 1px none rgb(0, 0, 0); text-align: center; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;"> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:center;">Remaining Contractual Maturity of the Agreements</p> </td><td style="border-bottom: 1px none rgb(0, 0, 0); font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td></tr> <tr style="vertical-align: bottom;"><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td colspan="6" style="text-align: center; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt; border-bottom: 1px solid rgb(0, 0, 0);"> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:center;">Overnight and Continuous</p> </td><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt; border-bottom: 1px solid rgb(0, 0, 0);"> </td></tr> <tr style="vertical-align: bottom;"><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td colspan="2" style="text-align: center; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;"> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:center;">At June 30,</p> </td><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td colspan="2" style="text-align: center; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;"> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:center;">At December 31,</p> </td><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td></tr> <tr style="vertical-align: bottom;"><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td colspan="2" style="text-align: center; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt; border-bottom: 1px solid rgb(0, 0, 0);"> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:center;">2020</p> </td><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt; border-bottom: 1px solid rgb(0, 0, 0);"> </td><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td colspan="2" style="text-align: center; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt; border-bottom: 1px solid rgb(0, 0, 0);"> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:center;">2019</p> </td><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt; border-bottom: 1px solid rgb(0, 0, 0);"> </td></tr> <tr style="vertical-align: bottom; background-color: rgb(204, 238, 255);"><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt; width: 64%;"> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-top: 0pt; margin-bottom: 0pt;">Repurchase agreements:</p> </td><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td colspan="6" style="text-align: center; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;"> <p style="font-family:'Times New Roman', Times, serif;font-size:10pt;margin:0pt;text-align:center;"><em style="font: inherit;"><em style="font: inherit;">(In thousands)</em></em></p> </td><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td></tr> <tr style="vertical-align: bottom; background-color: rgb(255, 255, 255);"><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-top: 0pt; margin-bottom: 0pt; margin-left: 9pt;">Collateral securing borrowings:</p> </td><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="text-align: left; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="text-align: left; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td></tr> <tr style="vertical-align: bottom; background-color: rgb(204, 238, 255);"><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-top: 0pt; margin-bottom: 0pt; margin-left: 18pt;">Securities of U.S. Government sponsored entities</p> </td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">$</td><td style="width: 15%; text-align: right; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">-</td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;"> </td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">$</td><td style="width: 15%; text-align: right; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">65,833</td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;"> </td></tr> <tr style="vertical-align: bottom; background-color: rgb(255, 255, 255);"><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-top: 0pt; margin-bottom: 0pt; margin-left: 18pt;">Agency residential MBS</p> </td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="width: 15%; text-align: right; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">86,143</td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;"> </td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="width: 15%; text-align: right; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;">52,485</td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt;"> </td></tr> <tr style="vertical-align: bottom; background-color: rgb(204, 238, 255);"><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-top: 0pt; margin-bottom: 0pt; margin-left: 18pt;">Corporate securities</p> </td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; border-bottom: 1px solid black;"> </td><td style="width: 15%; text-align: right; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt; border-bottom: 1px solid black;">182,308</td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt; border-bottom: 1px solid black;"> </td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; border-bottom: 1px solid black;"> </td><td style="width: 15%; text-align: right; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt; border-bottom: 1px solid black;">146,253</td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt; border-bottom: 1px solid black;"> </td></tr> <tr style="vertical-align: bottom; background-color: rgb(255, 255, 255);"><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-top: 0pt; margin-bottom: 0pt; margin-left: 27pt;">Total collateral carrying value</p> </td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt; border-bottom: 3px double rgb(0, 0, 0);">$</td><td style="width: 15%; text-align: right; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt; border-bottom: 3px double rgb(0, 0, 0);">268,451</td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; border-bottom: 3px double rgb(0, 0, 0); margin-left: 0pt;"> </td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt; border-bottom: 3px double rgb(0, 0, 0);">$</td><td style="width: 15%; text-align: right; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt; border-bottom: 3px double rgb(0, 0, 0);">264,571</td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; border-bottom: 3px double rgb(0, 0, 0); margin-left: 0pt;"> </td></tr> <tr style="vertical-align: bottom; background-color: rgb(204, 238, 255);"><td style="font-family: "Times New Roman", Times, serif; font-size: 10pt;"> <p style="font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-top: 0pt; margin-bottom: 0pt;">Total short-term borrowed funds</p> </td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt; border-bottom: 3px double rgb(0, 0, 0);">$</td><td style="width: 15%; text-align: right; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt; border-bottom: 3px double rgb(0, 0, 0);">86,170</td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; border-bottom: 3px double rgb(0, 0, 0); margin-left: 0pt;"> </td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt;"> </td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt; border-bottom: 3px double rgb(0, 0, 0);">$</td><td style="width: 15%; text-align: right; font-family: "Times New Roman", Times, serif; font-size: 10pt; margin-left: 0pt; border-bottom: 3px double rgb(0, 0, 0);">30,928</td><td style="width: 1%; font-family: "Times New Roman", Times, serif; font-size: 10pt; border-bottom: 3px double rgb(0, 0, 0); margin-left: 0pt;"> </td></tr> </tbody></table>
CY2020Q2	us-gaap	Carrying Value Of Securities Sold Under Repurchase Agreements And Deposits Received For Securities Loaned CarryingValueOfSecuritiesSoldUnderRepurchaseAgreementsAndDepositsReceivedForSecuritiesLoaned	268451000	USD
CY2019Q4	us-gaap	Carrying Value Of Securities Sold Under Repurchase Agreements And Deposits Received For Securities Loaned CarryingValueOfSecuritiesSoldUnderRepurchaseAgreementsAndDepositsReceivedForSecuritiesLoaned	264571000	USD
CY2020Q2	us-gaap	Short Term Borrowings ShortTermBorrowings	86170000	USD
CY2019Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	30928000	USD
CY2020Q2	wabc	Loan Commitments Not Unconditionally Cancellable LoanCommitmentsNotUnconditionallyCancellable	40267000	USD
CY2020Q2	wabc	Unfunded Loan Commitments UnfundedLoanCommitments	289785000	USD
CY2019Q4	wabc	Unfunded Loan Commitments UnfundedLoanCommitments	265311000	USD
CY2019Q4	us-gaap	Guarantee Obligations Current Carrying Value GuaranteeObligationsCurrentCarryingValue	550000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	19562000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	19625000	USD
	us-gaap	Net Income Loss NetIncomeLoss	36524000	USD
	us-gaap	Net Income Loss NetIncomeLoss	39271000	USD
CY2020Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	26935000
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.73
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.35
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.46
CY2019Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	26942000
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	27001000
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	26892000
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.72
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.73
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.35
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.46
CY2020Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	26935000
CY2019Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	26942000
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	27001000
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	26892000
CY2020Q2	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	16000
CY2019Q2	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	45000
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	23000
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	58000
CY2020Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	26951000
CY2019Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	26987000
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	27024000
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	26950000
CY2020Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.72

Files In Submission

Name	View Source	Status
0001171843-20-005542-index-headers.html	Edgar Link	pending
0001171843-20-005542-index.html	Edgar Link	pending
0001171843-20-005542.txt	Edgar Link	pending
0001171843-20-005542-xbrl.zip	Edgar Link	pending
ex_196370.htm	Edgar Link	pending
ex_196371.htm	Edgar Link	pending
ex_196372.htm	Edgar Link	pending
ex_196373.htm	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
Financial_Report.xlsx	Edgar Link	pending
MetaLinks.json	Edgar Link	pending
R1.htm	Edgar Link	pending
R10.htm	Edgar Link	pending
R11.htm	Edgar Link	pending
R12.htm	Edgar Link	pending
R13.htm	Edgar Link	pending
R14.htm	Edgar Link	pending
R15.htm	Edgar Link	pending
R16.htm	Edgar Link	pending
R17.htm	Edgar Link	pending
R18.htm	Edgar Link	pending
R19.htm	Edgar Link	pending
R2.htm	Edgar Link	pending
R20.htm	Edgar Link	pending
R21.htm	Edgar Link	pending
R22.htm	Edgar Link	pending
R23.htm	Edgar Link	pending
R24.htm	Edgar Link	pending
R25.htm	Edgar Link	pending
R26.htm	Edgar Link	pending
R27.htm	Edgar Link	pending
R28.htm	Edgar Link	pending
R29.htm	Edgar Link	pending
R3.htm	Edgar Link	pending
R30.htm	Edgar Link	pending
R31.htm	Edgar Link	pending
R32.htm	Edgar Link	pending
R33.htm	Edgar Link	pending
R34.htm	Edgar Link	pending
R35.htm	Edgar Link	pending
R36.htm	Edgar Link	pending
R37.htm	Edgar Link	pending
R38.htm	Edgar Link	pending
R39.htm	Edgar Link	pending
R4.htm	Edgar Link	pending
R40.htm	Edgar Link	pending
R41.htm	Edgar Link	pending
R42.htm	Edgar Link	pending
R43.htm	Edgar Link	pending
R44.htm	Edgar Link	pending
R45.htm	Edgar Link	pending
R46.htm	Edgar Link	pending
R47.htm	Edgar Link	pending
R48.htm	Edgar Link	pending
R49.htm	Edgar Link	pending
R5.htm	Edgar Link	pending
R50.htm	Edgar Link	pending
R51.htm	Edgar Link	pending
R52.htm	Edgar Link	pending
R53.htm	Edgar Link	pending
R54.htm	Edgar Link	pending
R55.htm	Edgar Link	pending
R56.htm	Edgar Link	pending
R57.htm	Edgar Link	pending
R58.htm	Edgar Link	pending
R59.htm	Edgar Link	pending
R6.htm	Edgar Link	pending
R60.htm	Edgar Link	pending
R61.htm	Edgar Link	pending
R62.htm	Edgar Link	pending
R63.htm	Edgar Link	pending
R64.htm	Edgar Link	pending
R65.htm	Edgar Link	pending
R66.htm	Edgar Link	pending
R67.htm	Edgar Link	pending
R68.htm	Edgar Link	pending
R69.htm	Edgar Link	pending
R7.htm	Edgar Link	pending
R8.htm	Edgar Link	pending
R9.htm	Edgar Link	pending
report.css	Edgar Link	pending
Show.js	Edgar Link	pending
wabc-20200630.xsd	Edgar Link	pending
wabc-20200630_cal.xml	Edgar Link	unprocessable
wabc-20200630_def.xml	Edgar Link	unprocessable
wabc-20200630_lab.xml	Edgar Link	unprocessable
wabc-20200630_pre.xml	Edgar Link	unprocessable
wabc20200630_10q.htm	Edgar Link	pending
wabc20200630_10q_htm.xml	Edgar Link	completed

Create your account

Find Stocks Worth Researching

Deeply Understand Businesses

Value Businesses Intelligently

$WABC
Westamerica Bancorp Stock $wabc

2020 Q2 Form 10-Q Financial Statement

#000117184320005542 Filed on August 05, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WABC Westamerica Bancorp Stock $wabc

2020 Q2 Form 10-Q Financial Statement

#000117184320005542 Filed on August 05, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WABC
Westamerica Bancorp Stock $wabc