$WAL
WESTERN ALLIANCE BANCORPORATION Stock $wal

$wal Overview Financials Valuation SEC Filings Company Website

2020 Q2 Form 10-Q Financial Statement

#000121254520000163 Filed on July 31, 2020

Income Statement

Concept	2020 Q2	2019 Q2	2019 Q1
Revenue	$318.2M	$302.9M	$291.1M
YoY Change	5.05%	20.39%	24.03%
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	$4.500M	$4.600M	$4.200M
YoY Change	-2.17%	35.29%	23.53%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense	$19.80M	$48.20M	$43.80M
YoY Change	-58.92%	75.31%	113.9%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$112.9M	$147.8M	$146.3M
YoY Change	-23.61%	13.69%	20.2%
Income Tax	$19.60M	$24.80M	$25.50M
% Of Pretax Income	17.36%	16.78%	17.43%
Net Earnings	$93.30M	$123.0M	$120.8M
YoY Change	-24.15%	17.5%	19.72%
Net Earnings / Revenue	29.32%	40.61%	41.5%
Basic Earnings Per Share	$0.93	$1.19	$1.16
Diluted Earnings Per Share	$0.93	$1.19	$1.16
COMMON SHARES
Basic Shares Outstanding	99.80M shares	103.0M shares	104.0M shares
Diluted Shares Outstanding	100.0M shares	103.5M shares	104.5M shares

Balance Sheet

Concept	2020 Q2	2019 Q2	2019 Q1
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$1.519B	$1.068B	$785.6M
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	$127.8M	$123.1M	$119.8M
YoY Change	3.85%	6.68%	2.68%
Goodwill		$289.9M	$289.9M
YoY Change		0.0%	0.0%
Intangibles		$8.486M	$8.873M
YoY Change		-15.61%	-15.13%
Long-Term Investments	$138.0M	$115.0M	$118.0M
YoY Change	20.0%	-19.58%
Other Assets	$34.00M	$9.000M	$22.00M
YoY Change	277.78%	-76.92%	-18.52%
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$31.91B	$25.31B	$23.79B
YoY Change	26.04%	18.47%	14.61%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses	$77.00M	$76.00M	$78.00M
YoY Change	1.32%
Deferred Revenue
YoY Change
Short-Term Debt	$10.00M	$0.00	$0.00
YoY Change		-100.0%	-100.0%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$77.00M	$76.00M	$78.00M
YoY Change	1.32%	322.22%	254.55%
LONG-TERM LIABILITIES
Long-Term Debt	$618.0M	$387.0M	$374.0M
YoY Change	59.69%	-11.24%	-43.67%
Other Long-Term Liabilities	$529.0M	$546.0M	$397.0M
YoY Change	-3.11%	25.81%	-7.03%
Total Long-Term Liabilities	$1.147B	$933.0M	$771.0M
YoY Change	22.94%	7.24%	-29.33%
TOTAL LIABILITIES
Total Short-Term Liabilities	$77.00M	$76.00M	$78.00M
Total Long-Term Liabilities	$1.147B	$933.0M	$771.0M
Total Liabilities	$28.80B	$22.46B	$21.07B
YoY Change	28.23%	18.38%	14.11%
SHAREHOLDERS EQUITY
Retained Earnings	$1.722B	$1.514B	$1.399B
YoY Change	13.77%	43.49%	47.22%
Common Stock	$10.00K	$10.00K	$10.00K
YoY Change	0.0%	0.0%	0.0%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$70.58M	$61.13M	$60.98M
YoY Change	15.46%	19.94%	31.23%
Treasury Stock Shares
Shareholders Equity	$3.102B	$2.851B	$2.721B
YoY Change
Total Liabilities & Shareholders Equity	$31.91B	$25.31B	$23.79B
YoY Change	26.04%	18.47%	14.61%

Cashflow Statement

Concept	2020 Q2	2019 Q2	2019 Q1
OPERATING ACTIVITIES
Net Income	$93.30M	$123.0M	$120.8M
YoY Change	-24.15%	17.5%	19.72%
Depreciation, Depletion And Amortization	$4.500M	$4.600M	$4.200M
YoY Change	-2.17%	35.29%	23.53%
Cash From Operating Activities	$159.4M	$179.0M	$151.3M
YoY Change	-10.95%	12.51%	71.33%
INVESTING ACTIVITIES
Capital Expenditures	-$3.100M	-$6.000M	-$3.200M
YoY Change	-48.33%	400.0%	433.33%
Acquisitions
YoY Change
Other Investing Activities	-$1.659B	-$1.087B	-$348.3M
YoY Change	52.68%	84.03%	0.46%
Cash From Investing Activities	-$1.662B	-$1.093B	-$351.5M
YoY Change	52.14%	84.67%	1.21%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net			$37.95M
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	2.606B	1.196B	$487.2M
YoY Change	117.9%	139.11%	73.02%
NET CHANGE
Cash From Operating Activities	159.4M	179.0M	$151.3M
Cash From Investing Activities	-1.662B	-1.093B	-$351.5M
Cash From Financing Activities	2.606B	1.196B	$487.2M
Net Change In Cash	1.103B	282.1M	$287.0M
YoY Change	290.89%	317.93%	1169.92%
FREE CASH FLOW
Cash From Operating Activities	$159.4M	$179.0M	$151.3M
Capital Expenditures	-$3.100M	-$6.000M	-$3.200M
Free Cash Flow	$162.5M	$185.0M	$154.5M
YoY Change	-12.16%	15.41%	73.78%

Facts In Submission

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	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
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	dei	Entity Central Index Key EntityCentralIndexKey	0001212545
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	dei	Document Type DocumentType	10-Q
	dei	Document Quarterly Report DocumentQuarterlyReport	true
	dei	Document Period End Date DocumentPeriodEndDate	2020-06-30
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	dei	Entity File Number EntityFileNumber	001-32550
	dei	Entity Registrant Name EntityRegistrantName	WESTERN ALLIANCE BANCORPORATION
	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	DE
	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	88-0365922
	dei	Entity Address Address Line1 EntityAddressAddressLine1	One E. Washington Street, Suite 1400
	dei	Entity Address City Or Town EntityAddressCityOrTown	Phoenix
	dei	Entity Address State Or Province EntityAddressStateOrProvince	AZ
	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	85004
	dei	City Area Code CityAreaCode	602
	dei	Local Phone Number LocalPhoneNumber	389-3500
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	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
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CY2020Q2	us-gaap	Derivative Instruments Not Designated As Hedging Instruments Gain Loss Net DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet	1159000	USD
CY2020Q2	us-gaap	Occupancy Net OccupancyNet	8101000	USD
CY2019Q2	us-gaap	Fees And Commissions Mortgage Banking And Servicing FeesAndCommissionsMortgageBankingAndServicing	5821000	USD
	us-gaap	Fees And Commissions Mortgage Banking And Servicing FeesAndCommissionsMortgageBankingAndServicing	11534000	USD
CY2019Q2	wal	Incomefrom Equity Investments IncomefromEquityInvestments	868000	USD
	wal	Incomefrom Equity Investments IncomefromEquityInvestments	5077000	USD
	us-gaap	Fees And Commissions Mortgage Banking And Servicing FeesAndCommissionsMortgageBankingAndServicing	11233000	USD
CY2020Q2	wal	Incomefrom Equity Investments IncomefromEquityInvestments	1311000	USD
	wal	Incomefrom Equity Investments IncomefromEquityInvestments	2877000	USD
CY2020Q2	wal	Card Income CardIncome	1178000	USD
	us-gaap	Derivative Instruments Not Designated As Hedging Instruments Gain Loss Net DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet	2487000	USD
	us-gaap	Derivative Instruments Not Designated As Hedging Instruments Gain Loss Net DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet	2243000	USD
CY2020Q2	wal	Lendingrelatedfees Lendingrelatedfees	719000	USD
CY2019Q2	wal	Lendingrelatedfees Lendingrelatedfees	553000	USD
	wal	Lendingrelatedfees Lendingrelatedfees	1367000	USD
	wal	Lendingrelatedfees Lendingrelatedfees	804000	USD
CY2020Q2	us-gaap	Realized Gain Loss On Marketable Securities Cost Method Investments And Other Investments RealizedGainLossOnMarketableSecuritiesCostMethodInvestmentsAndOtherInvestments	158000	USD
CY2019Q2	us-gaap	Realized Gain Loss On Marketable Securities Cost Method Investments And Other Investments RealizedGainLossOnMarketableSecuritiesCostMethodInvestmentsAndOtherInvestments	0	USD
	us-gaap	Realized Gain Loss On Marketable Securities Cost Method Investments And Other Investments RealizedGainLossOnMarketableSecuritiesCostMethodInvestmentsAndOtherInvestments	230000	USD
	us-gaap	Realized Gain Loss On Marketable Securities Cost Method Investments And Other Investments RealizedGainLossOnMarketableSecuritiesCostMethodInvestmentsAndOtherInvestments	0	USD
CY2020Q2	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	4432000	USD
CY2019Q2	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	1572000	USD
	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	-6868000	USD
	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	4406000	USD
CY2020Q2	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	513000	USD
CY2019Q2	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	1653000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	2025000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	2640000	USD
CY2020Q2	us-gaap	Noninterest Income NoninterestIncome	21270000	USD
CY2019Q2	us-gaap	Noninterest Income NoninterestIncome	14218000	USD
	us-gaap	Noninterest Income NoninterestIncome	26379000	USD
	us-gaap	Noninterest Income NoninterestIncome	29628000	USD
CY2020Q2	us-gaap	Labor And Related Expense LaborAndRelatedExpense	69634000	USD
CY2019Q2	us-gaap	Labor And Related Expense LaborAndRelatedExpense	65794000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	141698000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	134350000	USD
CY2020Q2	wal	Legal Professional And Director Fees LegalProfessionalAndDirectorFees	10669000	USD
CY2019Q2	wal	Legal Professional And Director Fees LegalProfessionalAndDirectorFees	11105000	USD
	wal	Legal Professional And Director Fees LegalProfessionalAndDirectorFees	21071000	USD
	wal	Legal Professional And Director Fees LegalProfessionalAndDirectorFees	18637000	USD
CY2020Q2	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	8577000	USD
CY2019Q2	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	6793000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	17180000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	13468000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	174000	USD
CY2019Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	147686000	USD
CY2020Q2	us-gaap	General Insurance Expense GeneralInsuranceExpense	3444000	USD
	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	-7262000	USD
	us-gaap	Noninterest Expense NoninterestExpense	226127000	USD
CY2020Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	112871000	USD
CY2019Q2	us-gaap	Occupancy Net OccupancyNet	7761000	USD
	us-gaap	Occupancy Net OccupancyNet	16326000	USD
	us-gaap	Occupancy Net OccupancyNet	15988000	USD
CY2020Q2	wal	Non Interest Expense Deposit Costs NonInterestExpenseDepositCosts	3514000	USD
CY2019Q2	wal	Non Interest Expense Deposit Costs NonInterestExpenseDepositCosts	7669000	USD
	wal	Non Interest Expense Deposit Costs NonInterestExpenseDepositCosts	10852000	USD
	wal	Non Interest Expense Deposit Costs NonInterestExpenseDepositCosts	13393000	USD
CY2019Q2	us-gaap	General Insurance Expense GeneralInsuranceExpense	2811000	USD
	us-gaap	General Insurance Expense GeneralInsuranceExpense	6442000	USD
	us-gaap	General Insurance Expense GeneralInsuranceExpense	5620000	USD
CY2020Q2	wal	Loan And Repossessed Asset Expense LoanAndRepossessedAssetExpense	2047000	USD
CY2019Q2	wal	Loan And Repossessed Asset Expense LoanAndRepossessedAssetExpense	1460000	USD
	wal	Loan And Repossessed Asset Expense LoanAndRepossessedAssetExpense	3509000	USD
	wal	Loan And Repossessed Asset Expense LoanAndRepossessedAssetExpense	3466000	USD
CY2020Q2	us-gaap	Marketing Expense MarketingExpense	869000	USD
CY2019Q2	us-gaap	Marketing Expense MarketingExpense	1057000	USD
	us-gaap	Marketing Expense MarketingExpense	1773000	USD
	us-gaap	Marketing Expense MarketingExpense	1798000	USD
CY2020Q2	us-gaap	Business Development BusinessDevelopment	831000	USD
CY2019Q2	us-gaap	Business Development BusinessDevelopment	1444000	USD
	us-gaap	Business Development BusinessDevelopment	3112000	USD
	us-gaap	Business Development BusinessDevelopment	3529000	USD
CY2020Q2	wal	Cardexpense Cardexpense	383000	USD
CY2019Q2	wal	Cardexpense Cardexpense	710000	USD
	wal	Cardexpense Cardexpense	1126000	USD
	wal	Cardexpense Cardexpense	1344000	USD
CY2020Q2	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	374000	USD
CY2019Q2	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	387000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	747000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	774000	USD
CY2020Q2	wal	Net Loss Gain On Sales Valuations Of Repossessed Assets And Bank Premises Net NetLossGainOnSalesValuationsOfRepossessedAssetsAndBankPremisesNet	-6000	USD
CY2019Q2	wal	Net Loss Gain On Sales Valuations Of Repossessed Assets And Bank Premises Net NetLossGainOnSalesValuationsOfRepossessedAssetsAndBankPremisesNet	-620000	USD
	wal	Net Loss Gain On Sales Valuations Of Repossessed Assets And Bank Premises Net NetLossGainOnSalesValuationsOfRepossessedAssetsAndBankPremisesNet	-1458000	USD
	wal	Net Loss Gain On Sales Valuations Of Repossessed Assets And Bank Premises Net NetLossGainOnSalesValuationsOfRepossessedAssetsAndBankPremisesNet	-523000	USD
CY2020Q2	us-gaap	Other Noninterest Expense OtherNoninterestExpense	6362000	USD
CY2019Q2	us-gaap	Other Noninterest Expense OtherNoninterestExpense	7878000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	12902000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	14283000	USD
CY2020Q2	us-gaap	Noninterest Expense NoninterestExpense	114799000	USD
CY2019Q2	us-gaap	Noninterest Expense NoninterestExpense	114249000	USD
	us-gaap	Noninterest Expense NoninterestExpense	235280000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	215343000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	294018000	USD
CY2020Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	19599000	USD
	us-gaap	Net Income Loss NetIncomeLoss	177236000	USD
	us-gaap	Net Income Loss NetIncomeLoss	243732000	USD
CY2019Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	24750000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	120000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	0	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	38107000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	50286000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	93272000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	122936000	USD
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.93
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.19
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.76
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.35
CY2020Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.93
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.19
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.76
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.34
CY2020Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	99792000	shares
CY2019Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	103019000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	100560000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	103523000	shares
CY2020Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	99993000	shares
CY2019Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	103501000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	100834000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	103985000	shares
CY2020Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.25
CY2019Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.50
	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	93272000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	122936000	USD
	us-gaap	Net Income Loss NetIncomeLoss	177236000	USD
	us-gaap	Net Income Loss NetIncomeLoss	243732000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	39308000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	35923000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	45584000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	67300000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	3000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	17000	USD
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	293000	USD
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	35000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	-3005000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	-1334000	USD
	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	3552000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	60003000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	230729000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	34572000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	48669000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	0	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	36180000	USD
CY2020Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	129452000	USD
CY2019Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	157508000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	225905000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	303735000	USD
CY2019Q1	us-gaap	Stockholders Equity StockholdersEquity	2720620000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	122936000	USD
CY2019Q2	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	7251000	USD
CY2019Q2	us-gaap	Restricted Stock Award Forfeitures RestrictedStockAwardForfeitures	151000	USD
CY2019Q2	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	-33964000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	34572000	USD
CY2019Q2	us-gaap	Stockholders Equity StockholdersEquity	2851264000	USD
CY2020Q1	us-gaap	Stockholders Equity StockholdersEquity	2999633000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	93272000	USD
CY2020Q2	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	27000	USD
CY2020Q2	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	8061000	USD
CY2020Q2	us-gaap	Restricted Stock Award Forfeitures RestrictedStockAwardForfeitures	397000	USD
CY2020Q2	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	-9149000	USD
CY2020Q2	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	-25213000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	36180000	USD
CY2020Q2	us-gaap	Stockholders Equity StockholdersEquity	3102414000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	2613734000	USD
	us-gaap	Net Income Loss NetIncomeLoss	243732000	USD
	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	36000	USD
	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	13723000	USD
	us-gaap	Restricted Stock Award Forfeitures RestrictedStockAwardForfeitures	8051000	USD
	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	-71913000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	60003000	USD
CY2019Q2	us-gaap	Stockholders Equity StockholdersEquity	2851264000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	3016748000	USD
CY2020Q1	us-gaap	Stockholders Equity StockholdersEquity	2991801000	USD
	us-gaap	Net Income Loss NetIncomeLoss	177236000	USD
	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	97000	USD
	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	14955000	USD
	us-gaap	Restricted Stock Award Forfeitures RestrictedStockAwardForfeitures	7855000	USD
	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	71669000	USD
	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	-50820000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	618903000	USD
	us-gaap	Net Income Loss NetIncomeLoss	177236000	USD
	us-gaap	Net Income Loss NetIncomeLoss	243732000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	48669000	USD
CY2020Q2	us-gaap	Stockholders Equity StockholdersEquity	3102414000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	143176000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	11500000	USD
	us-gaap	Depreciation And Amortization DepreciationAndAmortization	9526000	USD
	us-gaap	Depreciation And Amortization DepreciationAndAmortization	8798000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	14955000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	13723000	USD
	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	-23197000	USD
	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	3117000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-12129000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-6428000	USD
	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	19709000	USD
	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	20573000	USD
	us-gaap	Operating Lease Expense OperatingLeaseExpense	2846000	USD
	us-gaap	Operating Lease Expense OperatingLeaseExpense	2585000	USD
	us-gaap	Amortization Of Deferred Loan Origination Fees Net AmortizationOfDeferredLoanOriginationFeesNet	32561000	USD
	us-gaap	Amortization Of Deferred Loan Origination Fees Net AmortizationOfDeferredLoanOriginationFeesNet	21040000	USD
	us-gaap	Life Insurance Corporate Or Bank Owned Change In Value LifeInsuranceCorporateOrBankOwnedChangeInValue	2025000	USD
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	1959000	USD
	us-gaap	Debt And Equity Securities Realized Gain Loss DebtAndEquitySecuritiesRealizedGainLoss	230000	USD
	us-gaap	Debt And Equity Securities Realized Gain Loss DebtAndEquitySecuritiesRealizedGainLoss	0	USD
	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	-6868000	USD
	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	4406000	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	0	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	-513000	USD
	wal	Bank Owned Life Insurance Enhancement BankOwnedLifeInsuranceEnhancement	5607000	USD
	wal	Bank Owned Life Insurance Enhancement BankOwnedLifeInsuranceEnhancement	0	USD
	wal	Gain Loss On Foreclosed Assets GainLossOnForeclosedAssets	1472000	USD
	wal	Gain Loss On Foreclosed Assets GainLossOnForeclosedAssets	627000	USD
	wal	Valuation Adjustments Of Other Repossessed Assets Net ValuationAdjustmentsOfOtherRepossessedAssetsNet	-14000	USD
	wal	Valuation Adjustments Of Other Repossessed Assets Net ValuationAdjustmentsOfOtherRepossessedAssetsNet	-99000	USD
	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	0	USD
	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	-5000	USD
	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	37965000	USD
	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-47239000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	283402000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	330280000	USD
	us-gaap	Payments To Acquire Available For Sale Securities PaymentsToAcquireAvailableForSaleSecurities	895699000	USD
	us-gaap	Payments To Acquire Available For Sale Securities PaymentsToAcquireAvailableForSaleSecurities	123848000	USD
	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	56060000	USD
	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	49174000	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	50820000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities ProceedsFromSaleOfAvailableForSaleSecurities	156629000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities ProceedsFromSaleOfAvailableForSaleSecurities	0	USD
	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	0	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	8329000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	4660000	USD
	us-gaap	Proceeds From Sale Of Held To Maturity Securities ProceedsFromSaleOfHeldToMaturitySecurities	0	USD
	us-gaap	Proceeds From Sale Of Held To Maturity Securities ProceedsFromSaleOfHeldToMaturitySecurities	10000000	USD
	wal	Paymentsto Acquire Securities Equity PaymentstoAcquireSecuritiesEquity	7915000	USD
	wal	Paymentsto Acquire Securities Equity PaymentstoAcquireSecuritiesEquity	283000	USD
	us-gaap	Proceeds From Dividends Received ProceedsFromDividendsReceived	4118000	USD
	us-gaap	Proceeds From Dividends Received ProceedsFromDividendsReceived	4695000	USD
	wal	Purchase Of Investment Tax Credits PurchaseOfInvestmentTaxCredits	62535000	USD
	wal	Purchase Of Investment Tax Credits PurchaseOfInvestmentTaxCredits	38607000	USD
	wal	Purchaseof Sbic Investments PurchaseofSBICInvestments	-3065000	USD
	wal	Purchaseof Sbic Investments PurchaseofSBICInvestments	3137000	USD
	wal	Proceedsfrom Sale Paymentsto Purchase Investment In Money Market ProceedsfromSalePaymentstoPurchaseInvestmentInMoneyMarket	0	USD
	wal	Proceedsfrom Sale Paymentsto Purchase Investment In Money Market ProceedsfromSalePaymentstoPurchaseInvestmentInMoneyMarket	-137000	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	5607000	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	0	USD
	us-gaap	Payments To Acquire Restricted Investments PaymentsToAcquireRestrictedInvestments	152000	USD
	us-gaap	Payments To Acquire Restricted Investments PaymentsToAcquireRestrictedInvestments	85000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	3826106000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	1463570000	USD
	us-gaap	Payments For Proceeds From Productive Assets PaymentsForProceedsFromProductiveAssets	19718000	USD
	us-gaap	Payments For Proceeds From Productive Assets PaymentsForProceedsFromProductiveAssets	9164000	USD
	us-gaap	Proceeds From Sale Of Wholly Owned Real Estate And Real Estate Acquired In Settlement Of Loans ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans	6413000	USD
	us-gaap	Proceeds From Sale Of Wholly Owned Real Estate And Real Estate Acquired In Settlement Of Loans ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans	628000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-4058235000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-1444179000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	4748093000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	2262452000	USD
	us-gaap	Proceeds From Issuance Of Subordinated Long Term Debt ProceedsFromIssuanceOfSubordinatedLongTermDebt	222093000	USD
	us-gaap	Proceeds From Issuance Of Subordinated Long Term Debt ProceedsFromIssuanceOfSubordinatedLongTermDebt	0	USD
	us-gaap	Proceeds From Repayments Of Debt ProceedsFromRepaymentsOfDebt	18761000	USD
	us-gaap	Proceeds From Repayments Of Debt ProceedsFromRepaymentsOfDebt	-499490000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	97000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	36000	USD
	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	7855000	USD
	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	8051000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	71669000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	71913000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	4858700000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	1683034000	USD
	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	1083867000	USD
	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	569135000	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	434596000	USD
CY2018Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	498572000	USD
CY2020Q2	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	1518463000	USD
CY2019Q2	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	1067707000	USD
	us-gaap	Interest Paid InterestPaid	61534000	USD
	us-gaap	Interest Paid InterestPaid	90507000	USD
	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	16357000	USD
	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	-26994000	USD
	wal	Number Of Wholly Owned Subsidiaries Non Bank Subsidiaries NumberOfWhollyOwnedSubsidiariesNonBankSubsidiaries	2	Subsidiary
CY2019Q4	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	0	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	167797000	USD
CY2019Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	18025000	USD
CY2019Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	8955000	USD
CY2019Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	1680317000	USD
	us-gaap	Use Of Estimates UseOfEstimates	<div style="line-height:120%;padding-top:12px;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;font-weight:bold;">Use of estimates</span></div><div style="line-height:120%;padding-top:12px;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Management's estimates and judgments are ongoing and are based on experience, current and expected future conditions, third-party evaluations and various other assumptions that management believes are reasonable under the circumstances. The results of these estimates form the basis for making judgments about the carrying values of assets and liabilities, as well as identifying and assessing the accounting treatment with respect to commitments and contingencies. Actual results may differ from those estimates and assumptions used in the Consolidated Financial Statements and related notes. Material estimates that are susceptible to significant changes in the near term, particularly to the extent that economic conditions worsen or persist longer than expected in an adverse state, relate to: the determination of the allowance for credit losses; certain assets and liabilities carried at fair value; and accounting for income taxes. </span></div>
	wal	Number Of Unconsolidated Subsidiaries NumberOfUnconsolidatedSubsidiaries	8	Subsidiary
	us-gaap	Prior Period Reclassification Adjustment Description PriorPeriodReclassificationAdjustmentDescription	<div style="line-height:120%;padding-top:12px;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;font-weight:bold;">Reclassifications</span></div><div style="line-height:120%;padding-top:12px;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">Certain amounts reported in prior periods may have been reclassified in the Consolidated Financial Statements to conform to the current presentation. The reclassifications have no effect on net income or stockholders’ equity as previously reported.</span></div>
CY2020Q2	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	22278000	USD
CY2020Q2	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	479380000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	42486000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	0	USD
CY2020Q2	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	521866000	USD
CY2020Q2	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	3428395000	USD
CY2020Q2	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	112918000	USD
CY2020Q2	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	24391000	USD
CY2020Q2	us-gaap	Available For Sale Securities AvailableForSaleSecurities	3516922000	USD
CY2020Q2	us-gaap	Equity Securities Fv Ni Cost EquitySecuritiesFvNiCost	140964000	USD
CY2020Q2	wal	Equitysecurities Fvni Accumulated Gross Unrealized Gain Before Tax EquitysecuritiesFVNIAccumulatedGrossUnrealizedGainBeforeTax	1779000	USD
CY2020Q2	wal	Equitysecurities Fvni Accumulated Gross Unrealized Loss Before Tax EquitysecuritiesFVNIAccumulatedGrossUnrealizedLossBeforeTax	4334000	USD
CY2020Q2	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	138409000	USD
CY2019Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	485107000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	31303000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	149000	USD
CY2019Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	516261000	USD
CY2019Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	3317928000	USD
CY2019Q4	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	48252000	USD
CY2019Q4	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	19870000	USD
CY2019Q4	us-gaap	Available For Sale Securities AvailableForSaleSecurities	3346310000	USD
CY2019Q4	us-gaap	Equity Securities Fv Ni Cost EquitySecuritiesFvNiCost	135319000	USD
CY2019Q4	wal	Equitysecurities Fvni Accumulated Gross Unrealized Gain Before Tax EquitysecuritiesFVNIAccumulatedGrossUnrealizedGainBeforeTax	3881000	USD
CY2019Q4	wal	Equitysecurities Fvni Accumulated Gross Unrealized Loss Before Tax EquitysecuritiesFVNIAccumulatedGrossUnrealizedLossBeforeTax	499000	USD
CY2019Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	138701000	USD
CY2020Q2	us-gaap	Pledged Financial Instruments Not Separately Reported Other Debt Securities Available For Sale Or Held For Investment PledgedFinancialInstrumentsNotSeparatelyReportedOtherDebtSecuritiesAvailableForSaleOrHeldForInvestment	950700000	USD
CY2019Q4	us-gaap	Pledged Financial Instruments Not Separately Reported Other Debt Securities Available For Sale Or Held For Investment PledgedFinancialInstrumentsNotSeparatelyReportedOtherDebtSecuritiesAvailableForSaleOrHeldForInvestment	962500000	USD
CY2020Q2	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	2113000	USD
CY2020Q2	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	158197000	USD
CY2020Q2	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	116869000	USD
CY2020Q2	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	24391000	USD
CY2020Q2	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue	275066000	USD
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	4023000	USD
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	799113000	USD
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	15847000	USD
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	585688000	USD
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	19870000	USD
CY2019Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue	1384801000	USD
CY2020Q2	us-gaap	Availableforsale Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions1 AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1	50	positions
CY2019Q4	us-gaap	Availableforsale Securities In Unrealized Loss Positions Qualitative Disclosure Number Of Positions1 AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1	158	positions
CY2020Q1	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	2981000	USD
CY2020Q2	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	4668000	USD
CY2020Q2	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Writeoff DebtSecuritiesHeldToMaturityAllowanceForCreditLossWriteoff	0	USD
CY2020Q2	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Recovery DebtSecuritiesHeldToMaturityAllowanceForCreditLossRecovery	0	USD
CY2020Q2	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	7649000	USD
CY2020Q1	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	2646000	USD
	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	5003000	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	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	7649000	USD
CY2020Q2	us-gaap	Accrued Investment Income Receivable AccruedInvestmentIncomeReceivable	1600000	USD
CY2020Q2	us-gaap	Available For Sale Securities AvailableForSaleSecurities	3516922000	USD
CY2020Q2	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	138409000	USD
CY2019Q4	us-gaap	Available For Sale Securities AvailableForSaleSecurities	3346310000	USD
CY2019Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	138701000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount	7330000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Fair Value HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue	7361000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount	17226000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Net Reported Amount LoansAndLeasesReceivableNetReportedAmount	20933696000	USD
CY2020Q2	us-gaap	Loans And Leases Receivable Deferred Income LoansAndLeasesReceivableDeferredIncome	80600000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	17743000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount	454824000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue	496762000	USD
CY2020Q2	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	479380000	USD
CY2020Q2	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	521866000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	6705000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	6715000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	173884000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	161998000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	849577000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	891556000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost	2398229000	USD
CY2020Q2	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	2456653000	USD
CY2020Q2	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	3428395000	USD
CY2020Q2	us-gaap	Available For Sale Securities AvailableForSaleSecurities	3516922000	USD
CY2020Q2	us-gaap	Available For Sale Securities Gross Realized Gains AvailableForSaleSecuritiesGrossRealizedGains	200000	USD
CY2019Q2	us-gaap	Available For Sale Securities Gross Realized Gains AvailableForSaleSecuritiesGrossRealizedGains	0	USD
	us-gaap	Available For Sale Securities Gross Realized Gains AvailableForSaleSecuritiesGrossRealizedGains	405000	USD
	us-gaap	Available For Sale Securities Gross Realized Gains AvailableForSaleSecuritiesGrossRealizedGains	0	USD
CY2020Q2	us-gaap	Available For Sale Securities Gross Realized Losses AvailableForSaleSecuritiesGrossRealizedLosses	-42000	USD
CY2019Q2	us-gaap	Available For Sale Securities Gross Realized Losses AvailableForSaleSecuritiesGrossRealizedLosses	0	USD
	us-gaap	Available For Sale Securities Gross Realized Losses AvailableForSaleSecuritiesGrossRealizedLosses	-175000	USD
	us-gaap	Available For Sale Securities Gross Realized Losses AvailableForSaleSecuritiesGrossRealizedLosses	0	USD
CY2020Q2	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	158000	USD
CY2019Q2	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	0	USD
	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	230000	USD
	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	0	USD
CY2020Q2	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	25009215000	USD
CY2020Q2	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	310550000	USD
CY2020Q2	us-gaap	Loans And Leases Receivable Net Reported Amount LoansAndLeasesReceivableNetReportedAmount	24698665000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	21101493000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	167797000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Deferred Income LoansAndLeasesReceivableDeferredIncome	47700000	USD
CY2020Q2	us-gaap	Receivable With Imputed Interest Premium ReceivableWithImputedInterestPremium	29700000	USD
CY2019Q4	us-gaap	Receivable With Imputed Interest Premium ReceivableWithImputedInterestPremium	29900000	USD
CY2020Q2	us-gaap	Loans Receivable Held For Sale Amount LoansReceivableHeldForSaleAmount	20200000	USD
CY2019Q4	us-gaap	Loans Receivable Held For Sale Amount LoansReceivableHeldForSaleAmount	21800000	USD
CY2020Q2	us-gaap	Financing Receivable Nonaccrual No Allowance FinancingReceivableNonaccrualNoAllowance	74525000	USD
CY2020Q2	wal	Financing Receivable Nonaccrual With Allowance FinancingReceivableNonaccrualWithAllowance	44983000	USD
CY2020Q2	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	119508000	USD
CY2020Q2	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	0	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	55968000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	0	USD
CY2020Q2	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	1700000	USD
CY2019Q2	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	500000	USD
	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	2400000	USD
	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	800000	USD
CY2020Q2	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	24967011000	USD
CY2020Q2	us-gaap	Financing Receivable Recorded Investment Past Due FinancingReceivableRecordedInvestmentPastDue	42204000	USD
CY2020Q2	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	25009215000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	21065187000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Past Due FinancingReceivableRecordedInvestmentPastDue	36306000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	21101493000	USD
CY2020Q2	us-gaap	Financing Receivable Originated In Current Fiscal Year FinancingReceivableOriginatedInCurrentFiscalYear	3765301000	USD
CY2020Q2	us-gaap	Financing Receivable Originated In Fiscal Year Before Latest Fiscal Year FinancingReceivableOriginatedInFiscalYearBeforeLatestFiscalYear	5842053000	USD
CY2020Q2	us-gaap	Financing Receivable Originated Two Years Before Latest Fiscal Year FinancingReceivableOriginatedTwoYearsBeforeLatestFiscalYear	3520783000	USD
CY2020Q2	us-gaap	Financing Receivable Originated Three Years Before Latest Fiscal Year FinancingReceivableOriginatedThreeYearsBeforeLatestFiscalYear	2035238000	USD
CY2020Q2	us-gaap	Financing Receivable Originated Four Years Before Latest Fiscal Year FinancingReceivableOriginatedFourYearsBeforeLatestFiscalYear	829587000	USD
CY2020Q2	us-gaap	Financing Receivable Originated Five Or More Years Before Latest Fiscal Year FinancingReceivableOriginatedFiveOrMoreYearsBeforeLatestFiscalYear	2136182000	USD
CY2020Q2	us-gaap	Financing Receivable Revolving FinancingReceivableRevolving	6880071000	USD
CY2020Q2	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	25009215000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	21101493000	USD
CY2019Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	21065187000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	21101493000	USD
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	36700000	USD
CY2020Q2	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	2
CY2020Q2	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	10800000	USD
CY2020Q2	us-gaap	Loans And Leases Receivable Impaired Commitment To Lend LoansAndLeasesReceivableImpairedCommitmentToLend	300000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	17007000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	310550000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	10500000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	160409000	USD
CY2020Q2	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	24693694000	USD
CY2020Q2	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	315521000	USD
CY2020Q2	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	25009215000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	293543000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	8
	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	36743000	USD
CY2019Q2	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	2
CY2019Q2	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	1800000	USD
	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	4
	us-gaap	Financing Receivable Modifications Pre Modification Recorded Investment2 FinancingReceivableModificationsPreModificationRecordedInvestment2	28900000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Impaired Commitment To Lend LoansAndLeasesReceivableImpairedCommitmentToLend	200000	USD
CY2020Q2	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	0
	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	2
	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	400000	USD
CY2020Q2	us-gaap	Loans And Leases Receivable Collateral For Secured Borrowings LoansAndLeasesReceivableCollateralForSecuredBorrowings	138359000	USD
CY2020Q2	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	36300000	USD
CY2019Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	9000000.0	USD
CY2020Q1	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	235329000	USD
CY2020Q2	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	80685000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	5723000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	-259000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	310550000	USD
CY2020Q1	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	186925000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	125926000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	5820000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	3519000	USD
CY2020Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	310550000	USD
CY2020Q2	us-gaap	Interest Receivable InterestReceivable	107100000	USD
CY2019Q1	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	154987000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	2556000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	-978000	USD
CY2019Q2	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	7000000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	160409000	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	152717000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	4869000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	-2061000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	20979000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	95324000	USD
CY2019Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	116303000	USD
CY2019Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	20932161000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	21101493000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance	24055000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance	99440000	USD
CY2019Q4	wal	Impaired Financing Receivable Unpaid Principal Balance Individually Evaluated For Impairment ImpairedFinancingReceivableUnpaidPrincipalBalanceIndividuallyEvaluatedForImpairment	123495000	USD
CY2019Q4	wal	Financing Receivable Unpaid Principal Balance Collectively Evaluated For Impairment FinancingReceivableUnpaidPrincipalBalanceCollectivelyEvaluatedForImpairment	20921137000	USD
CY2019Q4	wal	Financing Receivable Unpaid Principal Balance FinancingReceivableUnpaidPrincipalBalance	21108472000	USD
CY2019Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	2776000	USD
CY2019Q4	wal	Impaired Financing Receivable With No Related Allowance ImpairedFinancingReceivableWithNoRelatedAllowance	0	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	2776000	USD
CY2019Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	164923000	USD
CY2019Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	167797000	USD
CY2020Q2	us-gaap	Financing Receivable Significant Purchases FinancingReceivableSignificantPurchases	530700000	USD
	us-gaap	Financing Receivable Significant Purchases FinancingReceivableSignificantPurchases	1198324000	USD
	us-gaap	Financing Receivable Purchased With Credit Deterioration Amount At Purchase Price FinancingReceivablePurchasedWithCreditDeteriorationAmountAtPurchasePrice	0	USD
CY2019Q2	us-gaap	Financing Receivable Significant Purchases FinancingReceivableSignificantPurchases	590609000	USD
CY2019Q2	us-gaap	Financing Receivable Significant Sales FinancingReceivableSignificantSales	19330000	USD
	us-gaap	Financing Receivable Significant Purchases FinancingReceivableSignificantPurchases	1121106000	USD
	us-gaap	Financing Receivable Significant Sales FinancingReceivableSignificantSales	34830000	USD
CY2019Q1	us-gaap	Loans And Leases Receivable Gain Loss On Sales Net LoansAndLeasesReceivableGainLossOnSalesNet	-100000	USD
	us-gaap	Loans And Leases Receivable Gain Loss On Sales Net LoansAndLeasesReceivableGainLossOnSalesNet	-500000	USD
CY2020Q2	us-gaap	Federal Funds Purchased FederalFundsPurchased	0	USD
CY2019Q4	us-gaap	Federal Funds Purchased FederalFundsPurchased	0	USD
CY2020Q2	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due Within One Year Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate	10000000	USD
CY2019Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due Within One Year Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate	0	USD
CY2020Q2	us-gaap	Short Term Borrowings ShortTermBorrowings	10000000	USD
CY2019Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	0	USD
CY2020Q2	us-gaap	Federal Funds Purchased FederalFundsPurchased	0	USD
CY2020Q2	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due Within One Year Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate	10000000.0	USD
CY2020Q2	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	25400000	USD
CY2019Q4	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	16700000	USD
CY2020Q1	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	37497000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	36300000	USD
CY2020Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.93
CY2020Q2	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	120000	USD
CY2020Q2	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	73677000	USD
CY2019Q1	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-8191000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	36180000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	34572000	USD
CY2019Q2	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	0	USD
CY2020Q2	us-gaap	Subordinated Debt SubordinatedDebt	547900000	USD
CY2019Q4	us-gaap	Subordinated Debt SubordinatedDebt	319200000	USD
	wal	Numberof Statutory Business Trusts Formedor Acquired NumberofStatutoryBusinessTrustsFormedorAcquired	8	Trust
CY2020Q2	us-gaap	Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust	69800000	USD
CY2019Q4	us-gaap	Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust	74400000	USD
	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod	136334	shares
CY2020Q2	us-gaap	Stock Repurchase Program Authorized Amount1 StockRepurchaseProgramAuthorizedAmount1	250000000.0	USD
CY2020Q2	us-gaap	Stock Repurchased And Retired During Period Shares StockRepurchasedAndRetiredDuringPeriodShares	297000	shares
	us-gaap	Stock Repurchased And Retired During Period Shares StockRepurchasedAndRetiredDuringPeriodShares	2066479	shares
CY2020Q2	wal	Weighted Average Selling Price Per Share WeightedAverageSellingPricePerShare	30.77
	wal	Weighted Average Selling Price Per Share WeightedAverageSellingPricePerShare	34.65
CY2020Q2	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	-9100000	USD
	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	71700000	USD
CY2019Q2	us-gaap	Stock Repurchased And Retired During Period Shares StockRepurchasedAndRetiredDuringPeriodShares	792688	shares
	us-gaap	Stock Repurchased And Retired During Period Shares StockRepurchasedAndRetiredDuringPeriodShares	1733603	shares
CY2019Q2	wal	Weighted Average Selling Price Per Share WeightedAverageSellingPricePerShare	42.81
	wal	Weighted Average Selling Price Per Share WeightedAverageSellingPricePerShare	41.45
CY2019Q2	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	-34000000.0	USD
	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	-71900000	USD
CY2020Q2	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.25
	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.25
CY2020Q2	us-gaap	Shares Paid For Tax Withholding For Share Based Compensation SharesPaidForTaxWithholdingForShareBasedCompensation	11055	shares
	us-gaap	Shares Paid For Tax Withholding For Share Based Compensation SharesPaidForTaxWithholdingForShareBasedCompensation	150166	shares
CY2020Q2	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	35.96
	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	52.31
CY2019Q2	us-gaap	Shares Paid For Tax Withholding For Share Based Compensation SharesPaidForTaxWithholdingForShareBasedCompensation	3145	shares
	us-gaap	Shares Paid For Tax Withholding For Share Based Compensation SharesPaidForTaxWithholdingForShareBasedCompensation	176152	shares
CY2019Q2	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	47.16
	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	45.69
CY2019Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	34572000	USD
CY2019Q1	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.1710
CY2020Q2	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	34100000	USD
	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	16000000.0	USD
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.34
	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
CY2019Q2	us-gaap	Collateral Already Posted Aggregate Fair Value CollateralAlreadyPostedAggregateFairValue	20300000	USD
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.19
CY2019Q2	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	26381000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	25008000	USD
	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	48843000	USD
	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	174000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	48669000	USD
CY2020Q2	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	73677000	USD
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-33622000	USD
	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	60003000	USD
	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	0	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	60003000	USD
CY2019Q2	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	26381000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	158000	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	230000	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 Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	-38000	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	-56000	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 Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	120000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	0	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	174000	USD
	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	0	USD
CY2020Q2	us-gaap	Hedged Asset Fair Value Hedge HedgedAssetFairValueHedge	619833000	USD
CY2020Q2	us-gaap	Hedged Asset Fair Value Hedge Cumulative Increase Decrease HedgedAssetFairValueHedgeCumulativeIncreaseDecrease	101315000	USD
CY2019Q4	us-gaap	Hedged Asset Fair Value Hedge HedgedAssetFairValueHedge	578063000	USD
CY2019Q4	us-gaap	Hedged Asset Fair Value Hedge Cumulative Increase Decrease HedgedAssetFairValueHedgeCumulativeIncreaseDecrease	53292000	USD
CY2020Q2	us-gaap	Hedged Liability Fair Value Hedge HedgedLiabilityFairValueHedge	-325826000	USD
CY2020Q2	us-gaap	Hedged Liability Fair Value Hedge Cumulative Increase Decrease HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease	-5966000	USD
CY2019Q4	us-gaap	Hedged Liability Fair Value Hedge HedgedLiabilityFairValueHedge	-319197000	USD
CY2019Q4	us-gaap	Hedged Liability Fair Value Hedge Cumulative Increase Decrease HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease	401000	USD
CY2020Q2	us-gaap	Derivative Collateral Right To Reclaim Securities DerivativeCollateralRightToReclaimSecurities	15900000	USD
CY2019Q4	us-gaap	Derivative Collateral Right To Reclaim Securities DerivativeCollateralRightToReclaimSecurities	29200000	USD
CY2020Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	99993000	shares
CY2019Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	103501000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	100834000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	103985000	shares
CY2020Q2	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.1736
CY2020Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	93272000	USD
CY2019Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	122936000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	177236000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	243732000	USD
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.93
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	462000	shares
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.19
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.76
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.35
	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	-7262000	USD
CY2019Q2	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.1676
CY2020Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	99792000	shares
CY2019Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	103019000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	100560000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	103523000	shares
CY2020Q2	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	201000	shares
CY2019Q2	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	482000	shares
	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	274000	shares
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.76
CY2020Q2	us-gaap	Operating Loss Carryforwards Valuation Allowance OperatingLossCarryforwardsValuationAllowance	0	USD
CY2020Q1	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.1770
CY2020Q2	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	34100000	USD
CY2019Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	147686000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	11500000	USD
CY2020Q2	us-gaap	Amortization Method Qualified Affordable Housing Project Investments AmortizationMethodQualifiedAffordableHousingProjectInvestments	438100000	USD
CY2019Q4	us-gaap	Amortization Method Qualified Affordable Housing Project Investments AmortizationMethodQualifiedAffordableHousingProjectInvestments	409400000	USD
CY2020Q2	us-gaap	Fair Value Liabilities Measured On Recurring Basis Subordinated Debt Obligations FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations	56974000	USD
CY2020Q2	us-gaap	Variable Interest Entity Nonconsolidated Carrying Amount Liabilities VariableInterestEntityNonconsolidatedCarryingAmountLiabilities	201900000	USD
CY2019Q4	us-gaap	Variable Interest Entity Nonconsolidated Carrying Amount Liabilities VariableInterestEntityNonconsolidatedCarryingAmountLiabilities	191000000.0	USD
CY2020Q2	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	12300000	USD
CY2019Q2	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	10500000	USD
	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	19700000	USD
	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	20600000	USD
	us-gaap	Line Of Credit Facility Expiration Period LineOfCreditFacilityExpirationPeriod	P1Y
CY2020Q2	us-gaap	Fair Value Disclosure Offbalance Sheet Risks Face Amount Liability FairValueDisclosureOffbalanceSheetRisksFaceAmountLiability	8272654000	USD
CY2019Q4	us-gaap	Fair Value Disclosure Offbalance Sheet Risks Face Amount Liability FairValueDisclosureOffbalanceSheetRisksFaceAmountLiability	8827108000	USD
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CY2020Q2	wal	Percentage Of Commercial Real Estate Loans Occupied By Owners PercentageOfCommercialRealEstateLoansOccupiedByOwners	0.30
CY2019Q4	wal	Percentage Of Commercial Real Estate Loans Occupied By Owners PercentageOfCommercialRealEstateLoansOccupiedByOwners	0.31
CY2020Q2	us-gaap	Lease Cost LeaseCost	3500000	USD
	us-gaap	Lease Cost LeaseCost	6900000	USD
CY2019Q2	us-gaap	Lease Cost LeaseCost	3100000	USD
	us-gaap	Lease Cost LeaseCost	6300000	USD
CY2020Q2	wal	Lesseeoperatingleaseothercost Lesseeoperatingleaseothercost	900000	USD
	wal	Lesseeoperatingleaseothercost Lesseeoperatingleaseothercost	2000000.0	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	-3005000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	-1334000	USD
	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	3552000	USD
CY2019Q4	us-gaap	Fair Value Liabilities Measured On Recurring Basis Subordinated Debt Obligations FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations	61685000	USD
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	490517000	USD
	us-gaap	Noninterest Income NoninterestIncome	29628000	USD
	us-gaap	Noninterest Expense NoninterestExpense	226127000	USD
CY2020Q2	us-gaap	Hedged Asset Fair Value Hedge Cumulative Increase Decrease HedgedAssetFairValueHedgeCumulativeIncreaseDecrease	101315000	USD
CY2020Q2	us-gaap	Hedged Liability Fair Value Hedge Cumulative Increase Decrease HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease	-5966000	USD
CY2019Q4	us-gaap	Hedged Asset Fair Value Hedge Cumulative Increase Decrease HedgedAssetFairValueHedgeCumulativeIncreaseDecrease	53292000	USD
CY2019Q4	us-gaap	Hedged Liability Fair Value Hedge Cumulative Increase Decrease HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease	401000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	-3000000.0	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	-1300000	USD
	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	3600000	USD
	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	-7300000	USD
CY2020Q2	wal	Collateral Dependent Loans Allowance CollateralDependentLoansAllowance	-15000000.0	USD
CY2020Q2	wal	Cash Cash Equivalentsand Investment Securities CashCashEquivalentsandInvestmentSecurities	5712300000	USD
CY2020Q2	us-gaap	Other Foreclosed Assets OtherForeclosedAssets	9400000	USD
CY2020Q2	us-gaap	Intangible Assets Net Including Goodwill IntangibleAssetsNetIncludingGoodwill	296900000	USD
CY2020Q2	wal	Other Assets Segment OtherAssetsSegment	1168900000	USD
CY2020Q2	us-gaap	Assets Assets	31906400000	USD
CY2020Q2	us-gaap	Deposits Deposits	27544600000	USD
CY2020Q2	wal	Borrowingsand Qualifying Debt BorrowingsandQualifyingDebt	627700000	USD
CY2020Q2	wal	Other Liabilities Segment OtherLiabilitiesSegment	631700000	USD
CY2020Q2	us-gaap	Liabilities Liabilities	28804000000.0	USD
CY2020Q2	us-gaap	Stockholders Equity StockholdersEquity	3102400000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	294018000	USD
CY2020Q2	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	31906400000	USD
CY2020Q2	us-gaap	Noninterest Expense NoninterestExpense	114799000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	50286000	USD
CY2020Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	112871000	USD
CY2019Q2	us-gaap	Noninterest Expense NoninterestExpense	114249000	USD
CY2019Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	24750000	USD
CY2020Q2	wal	Excess Funds Providedby Usedin Segment Basis ExcessFundsProvidedbyUsedinSegmentBasis	0	USD
CY2020Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	298400000	USD
CY2020Q2	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	92000000	USD
CY2020Q2	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	206400000	USD
CY2020Q2	us-gaap	Noninterest Income NoninterestIncome	21270000	USD
CY2020Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	19599000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	93272000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	567420000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	143176000	USD
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	424244000	USD
	us-gaap	Noninterest Income NoninterestIncome	26379000	USD
	us-gaap	Noninterest Expense NoninterestExpense	235280000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	215343000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	38107000	USD
	us-gaap	Net Income Loss NetIncomeLoss	177236000	USD
CY2019Q4	wal	Cash Cash Equivalentsand Investment Securities CashCashEquivalentsandInvestmentSecurities	4471200000	USD
CY2019Q4	wal	Loansand Leases Receivable Including Heldfor Sale Net LoansandLeasesReceivableIncludingHeldforSaleNet	20955500000	USD
CY2019Q4	us-gaap	Other Foreclosed Assets OtherForeclosedAssets	13900000	USD
CY2019Q4	us-gaap	Intangible Assets Net Including Goodwill IntangibleAssetsNetIncludingGoodwill	297600000	USD
CY2019Q4	wal	Other Assets Segment OtherAssetsSegment	1083700000	USD
CY2019Q4	us-gaap	Assets Assets	26821900000	USD
CY2019Q4	us-gaap	Deposits Deposits	22796500000	USD
CY2019Q4	wal	Borrowingsand Qualifying Debt BorrowingsandQualifyingDebt	393600000	USD
CY2019Q4	wal	Other Liabilities Segment OtherLiabilitiesSegment	615100000	USD
CY2019Q4	us-gaap	Liabilities Liabilities	23805200000	USD
CY2019Q4	us-gaap	Stockholders Equity StockholdersEquity	3016700000	USD
CY2019Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	26821900000	USD
CY2019Q4	wal	Excess Funds Providedby Usedin Segment Basis ExcessFundsProvidedbyUsedinSegmentBasis	0	USD
CY2019Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	254681000	USD
CY2019Q2	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	6964000	USD
CY2019Q2	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	247717000	USD
CY2019Q2	us-gaap	Noninterest Income NoninterestIncome	14218000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	122936000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	502017000	USD
CY2020Q2	wal	Success Fees SuccessFees	251000	USD
CY2020Q2	wal	Othernoninterestincome Othernoninterestincome	66000	USD
CY2020Q2	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	6381000	USD
	us-gaap	Net Income Loss NetIncomeLoss	243732000	USD
CY2020Q2	us-gaap	Fees And Commissions Mortgage Banking And Servicing FeesAndCommissionsMortgageBankingAndServicing	5130000	USD
CY2020Q2	wal	Debitandcreditcardinterchangefees Debitandcreditcardinterchangefees	934000	USD
CY2020Q2	wal	Otherrevenue Otherrevenue	14889000	USD
CY2020Q2	us-gaap	Noninterest Income NoninterestIncome	21270000	USD
	us-gaap	Fees And Commissions Mortgage Banking And Servicing FeesAndCommissionsMortgageBankingAndServicing	11534000	USD
	wal	Debitandcreditcardinterchangefees Debitandcreditcardinterchangefees	2344000	USD
	wal	Success Fees SuccessFees	386000	USD
	wal	Othernoninterestincome Othernoninterestincome	161000	USD
	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	14425000	USD
	wal	Otherrevenue Otherrevenue	11954000	USD
	us-gaap	Noninterest Income NoninterestIncome	26379000	USD
CY2019Q2	us-gaap	Fees And Commissions Mortgage Banking And Servicing FeesAndCommissionsMortgageBankingAndServicing	5821000	USD
CY2019Q2	wal	Debitandcreditcardinterchangefees Debitandcreditcardinterchangefees	1986000	USD
CY2019Q2	wal	Success Fees SuccessFees	85000	USD
CY2019Q2	wal	Othernoninterestincome Othernoninterestincome	-14000	USD
CY2019Q2	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	7878000	USD
CY2019Q2	wal	Otherrevenue Otherrevenue	6340000	USD
CY2019Q2	us-gaap	Noninterest Income NoninterestIncome	14218000	USD
	us-gaap	Fees And Commissions Mortgage Banking And Servicing FeesAndCommissionsMortgageBankingAndServicing	11233000	USD
	wal	Debitandcreditcardinterchangefees Debitandcreditcardinterchangefees	3853000	USD
	wal	Success Fees SuccessFees	520000	USD
	wal	Othernoninterestincome Othernoninterestincome	105000	USD
	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	15711000	USD
	wal	Otherrevenue Otherrevenue	13917000	USD
	us-gaap	Noninterest Income NoninterestIncome	29628000	USD
CY2020Q2	us-gaap	Accounts Receivable Net AccountsReceivableNet	1500000	USD
CY2019Q4	us-gaap	Accounts Receivable Net AccountsReceivableNet	1600000	USD

Files In Submission

Name	View Source	Status
0001212545-20-000163-index-headers.html	Edgar Link	pending
0001212545-20-000163-index.html	Edgar Link	pending
0001212545-20-000163.txt	Edgar Link	pending
0001212545-20-000163-xbrl.zip	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
Financial_Report.xlsx	Edgar Link	pending
MetaLinks.json	Edgar Link	pending
R1.htm	Edgar Link	pending
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R9999.htm	Edgar Link	pending
report.css	Edgar Link	pending
Show.js	Edgar Link	pending
wal-20200630.xsd	Edgar Link	pending
wal-20200630_cal.xml	Edgar Link	unprocessable
wal-20200630_def.xml	Edgar Link	unprocessable
wal-20200630_lab.xml	Edgar Link	unprocessable
wal-20200630_pre.xml	Edgar Link	unprocessable
wal630202010-q.htm	Edgar Link	pending
wal630202010-q_htm.xml	Edgar Link	completed
walex3116302020.htm	Edgar Link	pending
walex3126302020.htm	Edgar Link	pending
walex326302020.htm	Edgar Link	pending

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$WAL
WESTERN ALLIANCE BANCORPORATION Stock $wal

2020 Q2 Form 10-Q Financial Statement

#000121254520000163 Filed on July 31, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WAL WESTERN ALLIANCE BANCORPORATION Stock $wal

2020 Q2 Form 10-Q Financial Statement

#000121254520000163 Filed on July 31, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WAL
WESTERN ALLIANCE BANCORPORATION Stock $wal