$WAL
WESTERN ALLIANCE BANCORPORATION Stock $wal

$wal Overview Financials Valuation SEC Filings Company Website

2022 Q1 Form 10-Q Financial Statement

#000121254522000109 Filed on April 29, 2022

Income Statement

Concept	2022 Q1	2021 Q1
Revenue	$484.5M	$334.1M
YoY Change	45.02%	8.76%
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	$11.10M	$6.000M
YoY Change	85.0%	20.0%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense	$35.00M	$16.80M
YoY Change	108.33%	-56.02%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$298.2M	$234.4M
YoY Change	27.22%	128.91%
Income Tax	$58.10M	$41.90M
% Of Pretax Income	19.48%	17.88%
Net Earnings	$240.1M	$192.5M
YoY Change	24.73%	129.44%
Net Earnings / Revenue	49.56%	57.62%
Basic Earnings Per Share	$2.23	$1.91
Diluted Earnings Per Share	$2.22	$1.90
COMMON SHARES
Basic Shares Outstanding	106.0M shares	100.8M shares
Diluted Shares Outstanding	106.6M shares	101.4M shares

Balance Sheet

Concept	2022 Q1	2021 Q1
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$2.602B	$5.347B
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	$196.3M	$138.4M
YoY Change	41.84%	9.94%
Goodwill	$40.00M
YoY Change
Intangibles
YoY Change
Long-Term Investments	$165.0M	$193.0M
YoY Change	-14.51%	47.33%
Other Assets	$68.00M	$50.00M
YoY Change	36.0%	78.57%
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$60.58B	$43.40B
YoY Change	39.59%	48.83%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses	$155.0M	$85.00M
YoY Change	82.35%	7.59%
Deferred Revenue
YoY Change
Short-Term Debt	$70.30M	$5.000M
YoY Change	1306.0%	-98.38%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$155.0M	$85.00M
YoY Change	82.35%	7.59%
LONG-TERM LIABILITIES
Long-Term Debt	$1.656B	$544.0M
YoY Change	204.41%	-22.06%
Other Long-Term Liabilities	$1.524B	$642.0M
YoY Change	137.38%	21.59%
Total Long-Term Liabilities	$3.180B	$1.186B
YoY Change	168.13%	-3.26%
TOTAL LIABILITIES
Total Short-Term Liabilities	$155.0M	$85.00M
Total Long-Term Liabilities	$3.180B	$1.186B
Total Liabilities	$55.56B	$39.68B
YoY Change	40.02%	51.71%
SHAREHOLDERS EQUITY
Retained Earnings	$2.973B	$2.169B
YoY Change	37.07%	29.06%
Common Stock	$2.084B	$1.608B
YoY Change	29.57%	16081900.0%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$104.1M	$84.00M
YoY Change	23.93%	19.68%
Treasury Stock Shares	2.536M shares	2.324M shares
Shareholders Equity	$5.012B	$3.713B
YoY Change
Total Liabilities & Shareholders Equity	$60.58B	$43.40B
YoY Change	39.59%	48.83%

Cashflow Statement

Concept	2022 Q1	2021 Q1
OPERATING ACTIVITIES
Net Income	$240.1M	$192.5M
YoY Change	24.73%	129.44%
Depreciation, Depletion And Amortization	$11.10M	$6.000M
YoY Change	85.0%	20.0%
Cash From Operating Activities	-$622.9M	$100.1M
YoY Change	-722.28%	-19.27%
INVESTING ACTIVITIES
Capital Expenditures	-$26.20M	-$10.40M
YoY Change	151.92%	-37.35%
Acquisitions	$50.00M	$0.00
YoY Change
Other Investing Activities	-$2.571B	-$4.049B
YoY Change	-36.49%	70.16%
Cash From Investing Activities	$2.598B	-$4.059B
YoY Change	-164.0%	69.41%
FINANCING ACTIVITIES
Cash Dividend Paid	$40.50M	$25.30M
YoY Change	60.08%
Common Stock Issuance & Retirement, Net	$94.90M	-$209.2M
YoY Change	-145.36%	-434.72%
Debt Paid & Issued, Net	$9.500M	$0.00
YoY Change
Cash From Financing Activities	$4.061B	$6.634B
YoY Change	-38.79%	194.43%
NET CHANGE
Cash From Operating Activities	-$622.9M	$100.1M
Cash From Investing Activities	$2.598B	-$4.059B
Cash From Financing Activities	$4.061B	$6.634B
Net Change In Cash	$6.035B	$2.675B
YoY Change	125.64%	-14252.38%
FREE CASH FLOW
Cash From Operating Activities	-$622.9M	$100.1M
Capital Expenditures	-$26.20M	-$10.40M
Free Cash Flow	-$596.7M	$110.5M
YoY Change	-640.0%	-21.41%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
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CY2022Q1	dei	Entity Central Index Key EntityCentralIndexKey	0001212545
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CY2022Q1	dei	Document Type DocumentType	10-Q
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CY2022Q1	dei	Document Period End Date DocumentPeriodEndDate	2022-03-31
CY2022Q1	dei	Document Transition Report DocumentTransitionReport	false
CY2022Q1	dei	Entity File Number EntityFileNumber	001-32550
CY2022Q1	dei	Entity Registrant Name EntityRegistrantName	WESTERN ALLIANCE BANCORPORATION
CY2022Q1	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	DE
CY2022Q1	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	88-0365922
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CY2022Q1	us-gaap	Noninterest Expense NoninterestExpense	248600000	USD
CY2021Q1	us-gaap	Noninterest Expense NoninterestExpense	135000000.0	USD
CY2022Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	298200000	USD
CY2021Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	234400000	USD
CY2022Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	58100000	USD
CY2021Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	41900000	USD
CY2022Q1	us-gaap	Net Income Loss NetIncomeLoss	240100000	USD
CY2021Q1	us-gaap	Net Income Loss NetIncomeLoss	192500000	USD
CY2022Q1	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	3200000	USD
CY2021Q1	us-gaap	Preferred Stock Dividends Income Statement Impact PreferredStockDividendsIncomeStatementImpact	0	USD
CY2022Q1	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	236900000	USD
CY2021Q1	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	192500000	USD
CY2022Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.23
CY2021Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.91
CY2022Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.22
CY2021Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.90
CY2022Q1	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	106000000.0	shares
CY2021Q1	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	100800000	shares
CY2022Q1	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	106600000	shares
CY2021Q1	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	101400000	shares
CY2022Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.35
CY2021Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.25
CY2022Q1	us-gaap	Net Income Loss NetIncomeLoss	240100000	USD
CY2021Q1	us-gaap	Net Income Loss NetIncomeLoss	192500000	USD
CY2022Q1	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-80800000	USD
CY2021Q1	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-23500000	USD
CY2022Q1	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-247900000	USD
CY2021Q1	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-72000000.0	USD
CY2022Q1	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodTax	-700000	USD
CY2021Q1	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodTax	-100000	USD
CY2022Q1	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	-2200000	USD
CY2021Q1	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	-300000	USD
CY2022Q1	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	-1800000	USD
CY2021Q1	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax	0.0	USD
CY2022Q1	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	9800000	USD
CY2022Q1	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	17300000	USD
CY2022Q1	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	5100000	USD
CY2021Q1	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax	100000	USD
CY2022Q1	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-250800000	USD
CY2021Q1	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-72400000	USD
CY2022Q1	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-10700000	USD
CY2021Q1	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	120100000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	3413500000	USD
CY2021Q1	us-gaap	Net Income Loss NetIncomeLoss	192500000	USD
CY2021Q1	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	8100000	USD
CY2021Q1	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	12900000	USD
CY2021Q1	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	209200000	USD
CY2021Q1	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	25300000	USD
CY2021Q1	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-72400000	USD
CY2021Q1	us-gaap	Stockholders Equity StockholdersEquity	3712700000	USD
CY2021Q4	us-gaap	Stockholders Equity StockholdersEquity	4962600000	USD
CY2022Q1	us-gaap	Net Income Loss NetIncomeLoss	240100000	USD
CY2022Q1	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	107700000	USD
CY2022Q1	us-gaap	Dividends Preferred Stock Cash DividendsPreferredStockCash	3200000	USD
CY2022Q1	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	37300000	USD
CY2022Q1	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-250800000	USD
CY2022Q1	us-gaap	Stockholders Equity StockholdersEquity	5011600000	USD
CY2022Q1	us-gaap	Net Income Loss NetIncomeLoss	240100000	USD
CY2021Q1	us-gaap	Net Income Loss NetIncomeLoss	192500000	USD
CY2022Q1	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	9000000.0	USD
CY2021Q1	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	32400000	USD
CY2022Q1	us-gaap	Depreciation And Amortization DepreciationAndAmortization	11100000	USD
CY2021Q1	us-gaap	Depreciation And Amortization DepreciationAndAmortization	6000000.0	USD
CY2022Q1	us-gaap	Share Based Compensation ShareBasedCompensation	9800000	USD
CY2021Q1	us-gaap	Share Based Compensation ShareBasedCompensation	8000000.0	USD
CY2022Q1	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	35100000	USD
CY2021Q1	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	5100000	USD
CY2022Q1	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-6900000	USD
CY2021Q1	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-10700000	USD
CY2022Q1	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	13400000	USD
CY2021Q1	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	15500000	USD
CY2022Q1	us-gaap	Operating Lease Expense OperatingLeaseExpense	5400000	USD
CY2021Q1	us-gaap	Operating Lease Expense OperatingLeaseExpense	3000000.0	USD
CY2022Q1	us-gaap	Amortization Of Deferred Loan Origination Fees Net AmortizationOfDeferredLoanOriginationFeesNet	12500000	USD
CY2021Q1	us-gaap	Amortization Of Deferred Loan Origination Fees Net AmortizationOfDeferredLoanOriginationFeesNet	19200000	USD
CY2022Q1	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	13060000000	USD
CY2021Q1	us-gaap	Payments For Origination And Purchases Of Loans Held For Sale PaymentsForOriginationAndPurchasesOfLoansHeldForSale	0	USD
CY2022Q1	us-gaap	Proceeds From Sale And Collection Of Loans Heldforsale ProceedsFromSaleAndCollectionOfLoansHeldforsale	13663000000	USD
CY2021Q1	us-gaap	Proceeds From Sale And Collection Of Loans Heldforsale ProceedsFromSaleAndCollectionOfLoansHeldforsale	0	USD
CY2022Q1	us-gaap	Servicing Asset At Fair Value Additions ServicingAssetAtFairValueAdditions	204100000	USD
CY2021Q1	us-gaap	Servicing Asset At Fair Value Additions ServicingAssetAtFairValueAdditions	0	USD
CY2022Q1	us-gaap	Servicing Asset At Fair Value Period Increase Decrease ServicingAssetAtFairValuePeriodIncreaseDecrease	55400000	USD
CY2021Q1	us-gaap	Servicing Asset At Fair Value Period Increase Decrease ServicingAssetAtFairValuePeriodIncreaseDecrease	0	USD
CY2022Q1	us-gaap	Other Operating Activities Cash Flow Statement OtherOperatingActivitiesCashFlowStatement	-500000	USD
CY2021Q1	us-gaap	Other Operating Activities Cash Flow Statement OtherOperatingActivitiesCashFlowStatement	-800000	USD
CY2022Q1	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	39400000	USD
CY2021Q1	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	89900000	USD
CY2022Q1	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	-622900000	USD
CY2021Q1	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	100100000	USD
CY2022Q1	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	830600000	USD
CY2021Q1	us-gaap	Payments To Acquire Available For Sale Securities Debt PaymentsToAcquireAvailableForSaleSecuritiesDebt	2748500000	USD
CY2022Q1	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	-257100000	USD
CY2021Q1	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	493600000	USD
CY2022Q1	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	114200000	USD
CY2021Q1	us-gaap	Proceeds From Sale Of Available For Sale Securities Debt ProceedsFromSaleOfAvailableForSaleSecuritiesDebt	0	USD
CY2022Q1	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	60500000	USD
CY2021Q1	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	131600000	USD
CY2022Q1	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	6700000	USD
CY2021Q1	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	700000	USD
CY2022Q1	wal	Paymentsto Acquire Securities Equity PaymentstoAcquireSecuritiesEquity	4700000	USD
CY2021Q1	wal	Paymentsto Acquire Securities Equity PaymentstoAcquireSecuritiesEquity	28300000	USD
CY2022Q1	us-gaap	Payments For Proceeds From Investments PaymentsForProceedsFromInvestments	100000	USD
CY2021Q1	us-gaap	Payments For Proceeds From Investments PaymentsForProceedsFromInvestments	400000	USD
CY2022Q1	us-gaap	Proceeds From Sale Of Equity Securities Fv Ni ProceedsFromSaleOfEquitySecuritiesFvNi	0	USD
CY2021Q1	us-gaap	Proceeds From Sale Of Equity Securities Fv Ni ProceedsFromSaleOfEquitySecuritiesFvNi	600000	USD
CY2022Q1	us-gaap	Proceeds From Sale Of Mortgage Servicing Rights Msr ProceedsFromSaleOfMortgageServicingRightsMSR	24100000	USD
CY2021Q1	us-gaap	Proceeds From Sale Of Mortgage Servicing Rights Msr ProceedsFromSaleOfMortgageServicingRightsMSR	0	USD
CY2022Q1	wal	Purchase Of Other Investments PurchaseOfOtherInvestments	66100000	USD
CY2021Q1	wal	Purchase Of Other Investments PurchaseOfOtherInvestments	24300000	USD
CY2022Q1	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	1961700000	USD
CY2021Q1	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	1611100000	USD
CY2022Q1	us-gaap	Payments For Proceeds From Productive Assets PaymentsForProceedsFromProductiveAssets	26200000	USD
CY2021Q1	us-gaap	Payments For Proceeds From Productive Assets PaymentsForProceedsFromProductiveAssets	10400000	USD
CY2022Q1	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	50000000.0	USD
CY2021Q1	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	0	USD
CY2022Q1	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	2597600000	USD
CY2021Q1	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-4058900000	USD
CY2022Q1	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	4547500000	USD
CY2021Q1	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	6462600000	USD
CY2022Q1	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	9500000	USD
CY2021Q1	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	0	USD
CY2022Q1	us-gaap	Proceeds From Repayments Of Debt ProceedsFromRepaymentsOfDebt	-514500000	USD
CY2021Q1	us-gaap	Proceeds From Repayments Of Debt ProceedsFromRepaymentsOfDebt	-100000	USD
CY2022Q1	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	17300000	USD
CY2021Q1	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	12800000	USD
CY2022Q1	us-gaap	Payments Of Dividends PaymentsOfDividends	40500000	USD
CY2021Q1	us-gaap	Payments Of Dividends PaymentsOfDividends	25300000	USD
CY2022Q1	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	94900000	USD
CY2021Q1	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	209200000	USD
CY2022Q1	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	4060600000	USD
CY2021Q1	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	6633600000	USD
CY2022Q1	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	2085900000	USD
CY2021Q1	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	2674800000	USD
CY2021Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	516400000	USD
CY2020Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	2671700000	USD
CY2022Q1	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	2602300000	USD
CY2021Q1	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	5346500000	USD
CY2022Q1	us-gaap	Interest Paid Net InterestPaidNet	25900000	USD
CY2021Q1	us-gaap	Interest Paid Net InterestPaidNet	15000000.0	USD
CY2022Q1	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	24200000	USD
CY2021Q1	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	30800000	USD
CY2022Q1	wal	Net Increase Decrease In Unfunded Commitments And Obligations NetIncreaseDecreaseInUnfundedCommitmentsAndObligations	157400000	USD
CY2021Q1	wal	Net Increase Decrease In Unfunded Commitments And Obligations NetIncreaseDecreaseInUnfundedCommitmentsAndObligations	102800000	USD
CY2022Q1	wal	Net Increase In Unsettled Loans Hfi And Investment Securities Purchased NetIncreaseInUnsettledLoansHFIAndInvestmentSecuritiesPurchased	569100000	USD
CY2021Q1	wal	Net Increase In Unsettled Loans Hfi And Investment Securities Purchased NetIncreaseInUnsettledLoansHFIAndInvestmentSecuritiesPurchased	168500000	USD
CY2022Q1	wal	Transfers Of Securitized Lhfs To Afs Securities TransfersOfSecuritizedLHFSToAFSSecurities	40400000	USD
CY2021Q1	wal	Transfers Of Securitized Lhfs To Afs Securities TransfersOfSecuritizedLHFSToAFSSecurities	0	USD
CY2022Q1	wal	Number Of Wholly Owned Subsidiaries Non Bank Subsidiaries NumberOfWhollyOwnedSubsidiariesNonBankSubsidiaries	2	Subsidiary
CY2022Q1	us-gaap	Use Of Estimates UseOfEstimates	Use of estimatesThe 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: 1) the determination of the allowance for credit losses; 2) certain assets and liabilities carried at fair value; and 3) accounting for income taxes.
CY2022Q1	wal	Number Of Unconsolidated Subsidiaries NumberOfUnconsolidatedSubsidiaries	8	Subsidiary
CY2022Q1	us-gaap	Business Combination Contingent Consideration Liability BusinessCombinationContingentConsiderationLiability	17200000	USD
CY2022Q1	us-gaap	Prior Period Reclassification Adjustment Description PriorPeriodReclassificationAdjustmentDescription	<div style="margin-top:9pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Reclassifications</span></div><div style="margin-top:9pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Certain amounts in the Consolidated Income Statements for the prior periods have been reclassified to conform to the current presentation. The reclassifications have no effect on net income or stockholders’ equity as previously reported.</span></div>
CY2022Q1	wal	Acquisition And Restructure Expenses AcquisitionAndRestructureExpenses	400000	USD
CY2022Q1	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Cash And Equivalents BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents	600000	USD
CY2022Q1	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Intangibles BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles	27500000	USD
CY2022Q1	us-gaap	Business Combination Consideration Transferred1 BusinessCombinationConsiderationTransferred1	67800000	USD
CY2022Q1	us-gaap	Payments To Acquire Businesses Gross PaymentsToAcquireBusinessesGross	50600000	USD
CY2022Q1	us-gaap	Business Acquisition Effective Date Of Acquisition1 BusinessAcquisitionEffectiveDateOfAcquisition1	2022-01-25
CY2022Q1	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Other Noncurrent Assets BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets	100000	USD
CY2022Q1	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Assets BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets	28200000	USD
CY2022Q1	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Noncurrent Liabilities Other BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther	400000	USD
CY2022Q1	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Liabilities BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities	400000	USD
CY2022Q1	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Net BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet	27800000	USD
CY2022Q1	us-gaap	Payments To Acquire Businesses Gross PaymentsToAcquireBusinessesGross	50600000	USD
CY2022Q1	us-gaap	Business Combination Contingent Consideration Liability BusinessCombinationContingentConsiderationLiability	17200000	USD
CY2022Q1	us-gaap	Business Combination Consideration Transferred1 BusinessCombinationConsiderationTransferred1	67800000	USD
CY2022Q1	us-gaap	Goodwill Goodwill	40000000.0	USD
CY2022Q1	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Intangibles BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles	27500000	USD
CY2022Q1	us-gaap	Goodwill Goodwill	40000000	USD
CY2021Q2	us-gaap	Business Acquisition Effective Date Of Acquisition1 BusinessAcquisitionEffectiveDateOfAcquisition1	2021-04-07
CY2021	us-gaap	Payments To Acquire Businesses Gross PaymentsToAcquireBusinessesGross	1200000000	USD
CY2021Q1	wal	Acquisition And Restructure Expenses AcquisitionAndRestructureExpenses	400000	USD
CY2021Q2	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Cash And Equivalents BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents	207200000	USD
CY2021Q2	wal	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Loans Held For Sale BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLoansHeldForSale	3552900000	USD
CY2021Q2	wal	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Servicing Assets BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedServicingAssets	1347000000	USD
CY2021Q2	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Property Plant And Equipment BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment	11300000	USD
CY2021Q2	wal	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Operating Right Of Use Asset BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOperatingRightOfUseAsset	18900000	USD
CY2021Q2	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Intangibles BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles	141000000.0	USD
CY2021Q2	wal	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Loans Eligible For Repurchase BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLoansEligibleForRepurchase	2744700000	USD
CY2021Q2	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Deferred Tax Assets BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssets	6600000	USD
CY2021Q2	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Other Noncurrent Assets BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets	236000000.0	USD
CY2021Q2	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Assets BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets	8265600000	USD
CY2021Q2	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Noncurrent Liabilities Long Term Debt BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebt	3633900000	USD
CY2021Q2	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Capital Lease Obligation BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCapitalLeaseObligation	18900000	USD
CY2021Q2	wal	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Liability For Loans Eligible For Repurchase BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilityForLoansEligibleForRepurchase	2744700000	USD
CY2021Q2	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Noncurrent Liabilities Other BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther	149500000	USD
CY2021Q2	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Liabilities BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities	6547000000	USD
CY2021Q2	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Net BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet	1718600000	USD
CY2021Q1	us-gaap	Payments To Acquire Businesses Gross PaymentsToAcquireBusinessesGross	1231600000	USD
CY2021Q2	wal	Business Combination Elimination Of Pre Existing Debt And Other BusinessCombinationEliminationOfPreExistingDebtAndOther	686800000	USD
CY2021Q1	us-gaap	Business Combination Consideration Transferred1 BusinessCombinationConsiderationTransferred1	1918400000	USD
CY2021Q2	us-gaap	Goodwill Goodwill	199800000	USD
CY2021Q2	us-gaap	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Intangibles BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles	141000000	USD
CY2021Q2	us-gaap	Goodwill Goodwill	199800000	USD
CY2021Q2	us-gaap	Business Acquisition Purchase Price Allocation Goodwill Expected Tax Deductible Amount BusinessAcquisitionPurchasePriceAllocationGoodwillExpectedTaxDeductibleAmount	185000000	USD
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CY2022Q1	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	21300000	USD
CY2022Q1	wal	Business Acquisition Pro Forma Non Interest Income BusinessAcquisitionProFormaNonInterestIncome	89600000	USD
CY2022Q1	us-gaap	Business Acquisitions Pro Forma Net Income Loss BusinessAcquisitionsProFormaNetIncomeLoss	180200000	USD
CY2022Q1	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	1161000000	USD
CY2022Q1	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	18200000	USD
CY2022Q1	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	39300000	USD
CY2022Q1	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1139900000	USD
CY2022Q1	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	7165500000	USD
CY2022Q1	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	334600000	USD
CY2022Q1	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	6852200000	USD
CY2022Q1	us-gaap	Equity Securities Fv Ni Cost EquitySecuritiesFvNiCost	165100000	USD
CY2022Q1	wal	Equitysecurities Fvni Accumulated Gross Unrealized Gain Before Tax EquitysecuritiesFVNIAccumulatedGrossUnrealizedGainBeforeTax	4900000	USD
CY2022Q1	wal	Equitysecurities Fvni Accumulated Gross Unrealized Loss Before Tax EquitysecuritiesFVNIAccumulatedGrossUnrealizedLossBeforeTax	5300000	USD
CY2022Q1	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	164700000	USD
CY2021Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	1107100000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	43200000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	3900000	USD
CY2021Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	1146400000	USD
CY2021Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	6166500000	USD
CY2021Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	103600000	USD
CY2021Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	81300000	USD
CY2021Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	6188800000	USD
CY2021Q4	us-gaap	Equity Securities Fv Ni Cost EquitySecuritiesFvNiCost	152200000	USD
CY2021Q4	wal	Equitysecurities Fvni Accumulated Gross Unrealized Gain Before Tax EquitysecuritiesFVNIAccumulatedGrossUnrealizedGainBeforeTax	7700000	USD
CY2021Q4	wal	Equitysecurities Fvni Accumulated Gross Unrealized Loss Before Tax EquitysecuritiesFVNIAccumulatedGrossUnrealizedLossBeforeTax	1400000	USD
CY2021Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	158500000	USD
CY2022Q1	us-gaap	Pledged Financial Instruments Not Separately Reported Other Debt Securities Available For Sale Or Held For Investment PledgedFinancialInstrumentsNotSeparatelyReportedOtherDebtSecuritiesAvailableForSaleOrHeldForInvestment	1900000000	USD
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CY2022Q1	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	203500000	USD
CY2022Q1	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	4332400000	USD
CY2022Q1	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	3200000	USD
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CY2022Q1	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	131100000	USD
CY2022Q1	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	1134700000	USD
CY2022Q1	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	334600000	USD
CY2022Q1	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	5467100000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	67900000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	3046300000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	13400000	USD
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CY2021Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Accumulated Loss DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss	81300000	USD
CY2021Q4	us-gaap	Debt Securities Available For Sale Unrealized Loss Position DebtSecuritiesAvailableForSaleUnrealizedLossPosition	3215800000	USD
CY2022Q1	us-gaap	Debt Securities Available For Sale Unrealized Loss Position Number Of Positions DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions	575	positions
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CY2022Q1	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	2000000.0	USD
CY2022Q1	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Writeoff DebtSecuritiesHeldToMaturityAllowanceForCreditLossWriteoff	0	USD
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CY2021Q1	us-gaap	Debt Securities Held To Maturity Credit Loss Expense Reversal DebtSecuritiesHeldToMaturityCreditLossExpenseReversal	2400000	USD
CY2021Q1	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Writeoff DebtSecuritiesHeldToMaturityAllowanceForCreditLossWriteoff	0	USD
CY2021Q1	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss Recovery DebtSecuritiesHeldToMaturityAllowanceForCreditLossRecovery	0	USD
CY2021Q1	us-gaap	Debt Securities Held To Maturity Allowance For Credit Loss DebtSecuritiesHeldToMaturityAllowanceForCreditLoss	9200000	USD
CY2022Q1	us-gaap	Accrued Investment Income Receivable AccruedInvestmentIncomeReceivable	3300000	USD
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CY2022Q1	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	164700000	USD
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CY2021Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	6188800000	USD
CY2021Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	158500000	USD
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CY2022Q1	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Fair Value HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue	41700000	USD
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CY2022Q1	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	1046100000	USD
CY2022Q1	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	2405000000	USD
CY2022Q1	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	2376300000	USD
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CY2022Q1	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	3310400000	USD
CY2022Q1	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	7165500000	USD
CY2022Q1	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	6852200000	USD
CY2022Q1	us-gaap	Debt Securities Available For Sale Realized Gain Loss DebtSecuritiesAvailableForSaleRealizedGainLoss	6900000	USD
CY2022Q1	us-gaap	Loans Receivable Held For Sale Amount LoansReceivableHeldForSaleAmount	4761600000	USD
CY2021Q4	us-gaap	Loans Receivable Held For Sale Amount LoansReceivableHeldForSaleAmount	5635100000	USD
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CY2022Q1	wal	Msr Capitalized Upon Sale Of Loan MSRCapitalizedUponSaleOfLoan	204100000	USD
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CY2022Q1	us-gaap	Financing Receivable Nonaccrual No Allowance FinancingReceivableNonaccrualNoAllowance	34700000	USD
CY2022Q1	wal	Financing Receivable Nonaccrual With Allowance FinancingReceivableNonaccrualWithAllowance	56300000	USD
CY2022Q1	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	91000000.0	USD
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CY2021Q4	wal	Financing Receivable Nonaccrual With Allowance FinancingReceivableNonaccrualWithAllowance	33700000	USD
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CY2021Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	0	USD
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CY2022Q1	us-gaap	Financing Receivable Originated In Current Fiscal Year FinancingReceivableOriginatedInCurrentFiscalYear	3148300000	USD
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CY2022Q1	us-gaap	Financing Receivable Originated Two Years Before Latest Fiscal Year FinancingReceivableOriginatedTwoYearsBeforeLatestFiscalYear	3429200000	USD
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CY2022Q1	us-gaap	Financing Receivable Revolving FinancingReceivableRevolving	12288800000	USD
CY2022Q1	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	41119100000	USD
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CY2021Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	39075400000	USD
CY2022Q1	wal	Covid19 Related Loan Modifications COVID19RelatedLoanModifications	131400000	USD
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CY2021Q1	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	3	SecurityLoan
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CY2021Q1	us-gaap	Financing Receivable Modifications Subsequent Default Number Of Contracts1 FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1	0	SecurityLoan
CY2022Q1	us-gaap	Loans And Leases Receivable Collateral For Secured Borrowings LoansAndLeasesReceivableCollateralForSecuredBorrowings	266500000	USD
CY2021Q4	us-gaap	Loans And Leases Receivable Collateral For Secured Borrowings LoansAndLeasesReceivableCollateralForSecuredBorrowings	226800000	USD
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	252500000	USD
CY2022Q1	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	5300000	USD
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CY2022Q1	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	2400000	USD
CY2022Q1	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	257600000	USD
CY2020Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	278900000	USD
CY2021Q1	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	30400000	USD
CY2022Q1	wal	Msr Loan Sales Receivable MSRLoanSalesReceivable	58400000	USD
CY2021Q1	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	2100000	USD
CY2021Q1	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	700000	USD
CY2021Q1	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	247100000	USD
CY2022Q1	us-gaap	Interest Receivable InterestReceivable	201100000	USD
CY2021Q4	us-gaap	Interest Receivable InterestReceivable	197600000	USD
CY2021Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	37600000	USD
CY2020Q4	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	37000000.0	USD
CY2022Q1	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	5700000	USD
CY2021Q4	us-gaap	Senior Notes SeniorNotes	317900000	USD
CY2021Q1	us-gaap	Off Balance Sheet Credit Loss Liability Credit Loss Expense Reversal OffBalanceSheetCreditLossLiabilityCreditLossExpenseReversal	-4400000	USD
CY2022Q1	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	43300000	USD
CY2021Q1	us-gaap	Off Balance Sheet Credit Loss Liability OffBalanceSheetCreditLossLiability	32600000	USD
CY2021Q1	us-gaap	Shares Paid For Tax Withholding For Share Based Compensation SharesPaidForTaxWithholdingForShareBasedCompensation	154163	shares
CY2022Q1	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	40806000000	USD
CY2022Q1	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	313100000	USD
CY2022Q1	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	41119100000	USD
CY2022Q1	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	244000000.0	USD
CY2022Q1	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	13600000	USD
CY2022Q1	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	257600000	USD
CY2021Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	38812300000	USD
CY2021Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	263100000	USD
CY2021Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	39075400000	USD
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	236400000	USD
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	16100000	USD
CY2021Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	252500000	USD
CY2021Q4	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	698000000.0	USD
CY2022Q1	us-gaap	Servicing Asset At Fair Value Additions ServicingAssetAtFairValueAdditions	204100000	USD
CY2022Q1	us-gaap	Servicing Asset At Fair Value Disposals ServicingAssetAtFairValueDisposals	0	USD
CY2022Q1	us-gaap	Servicing Asset At Fair Value Changes In Fair Value Resulting From Changes In Valuation Inputs Or Changes In Assumptions ServicingAssetAtFairValueChangesInFairValueResultingFromChangesInValuationInputsOrChangesInAssumptions	81400000	USD
CY2022Q1	us-gaap	Servicing Asset At Fair Value Other Changes In Fair Value ServicingAssetAtFairValueOtherChangesInFairValue	-33200000	USD
CY2022Q1	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	950300000	USD
CY2022Q1	us-gaap	Continuing Involvement With Transferred Financial Assets Principal Amount Outstanding ContinuingInvolvementWithTransferredFinancialAssetsPrincipalAmountOutstanding	65546700000	USD
CY2022Q1	us-gaap	Contractually Specified Servicing Fees Late Fees And Ancillary Fees Earned In Exchange For Servicing Financial Assets ContractuallySpecifiedServicingFeesLateFeesAndAncillaryFeesEarnedInExchangeForServicingFinancialAssets	42900000	USD
CY2022Q1	wal	Servicing Advances Net ServicingAdvancesNet	-62800000	USD
CY2021Q4	wal	Servicing Advances Net ServicingAdvancesNet	-81600000	USD
CY2022Q1	us-gaap	Servicing Asset At Fair Value Amount ServicingAssetAtFairValueAmount	950300000	USD
CY2022Q1	wal	Sensitivity Analysis Of Fair Value Transferors Interests In Transferred Financial Assets Impact Of50 Basis Point Adverse Interest Rate Change SensitivityAnalysisOfFairValueTransferorsInterestsInTransferredFinancialAssetsImpactOf50BasisPointAdverseInterestRateChange	-30100000	USD
CY2022Q1	wal	Sensitivity Analysis Of Fair Value Transferors Interests In Transferred Financial Assets Impact Of50 Basis Point Favorable Interest Rate Change SensitivityAnalysisOfFairValueTransferorsInterestsInTransferredFinancialAssetsImpactOf50BasisPointFavorableInterestRateChange	17700000	USD
CY2022Q1	wal	Sensitivity Analysis Of Fair Value Transferors Interests In Transferred Financial Assets Impact Of50 Basis Point Discount Rate Increase SensitivityAnalysisOfFairValueTransferorsInterestsInTransferredFinancialAssetsImpactOf50BasisPointDiscountRateIncrease	18200000	USD
CY2022Q1	wal	Sensitivity Analysis Of Fair Value Transferors Interests In Transferred Financial Assets Impact Of50 Basis Point Discount Rate Decrease SensitivityAnalysisOfFairValueTransferorsInterestsInTransferredFinancialAssetsImpactOf50BasisPointDiscountRateDecrease	18900000	USD
CY2022Q1	wal	Sensitivity Analysis Of Fair Value Transferors Interests In Transferred Financial Assets Impact Of1 Percent Increase In Prepayment Speed SensitivityAnalysisOfFairValueTransferorsInterestsInTransferredFinancialAssetsImpactOf1PercentIncreaseInPrepaymentSpeed	24300000	USD
CY2022Q1	wal	Sensitivity Analysis Of Fair Value Transferors Interests In Transferred Financial Assets Impact Of1 Percent Decrease In Prepayment Speed SensitivityAnalysisOfFairValueTransferorsInterestsInTransferredFinancialAssetsImpactOf1PercentDecreaseInPrepaymentSpeed	26900000	USD
CY2022Q1	wal	Sensitivity Analysis Of Fair Value Transferors Interests In Transferred Financial Assets Impact Of10 Percent Increase Cost Of Service SensitivityAnalysisOfFairValueTransferorsInterestsInTransferredFinancialAssetsImpactOf10PercentIncreaseCostOfService	11900000	USD
CY2022Q1	wal	Sensitivity Analysis Of Fair Value Transferors Interests In Transferred Financial Assets Impact Of10 Percent Decrease Cost Of Service SensitivityAnalysisOfFairValueTransferorsInterestsInTransferredFinancialAssetsImpactOf10PercentDecreaseCostOfService	11900000	USD
CY2022Q1	us-gaap	Long Term Debt LongTermDebt	763000000.0	USD
CY2022Q1	us-gaap	Notes Payable NotesPayable	445500000	USD
CY2021Q4	us-gaap	Long Term Debt LongTermDebt	775000000.0	USD
CY2022Q1	us-gaap	Federal Funds Purchased FederalFundsPurchased	0	USD
CY2021Q4	us-gaap	Federal Funds Purchased FederalFundsPurchased	675000000.0	USD
CY2022Q1	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	18000000.0	USD
CY2021Q4	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	16600000	USD
CY2022Q1	us-gaap	Other Short Term Borrowings OtherShortTermBorrowings	52300000	USD
CY2021Q4	us-gaap	Other Short Term Borrowings OtherShortTermBorrowings	35300000	USD
CY2022Q1	us-gaap	Short Term Borrowings ShortTermBorrowings	70300000	USD
CY2021Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	726900000	USD
CY2022Q1	us-gaap	Senior Notes SeniorNotes	317500000	USD
CY2021Q4	us-gaap	Senior Notes SeniorNotes	317900000	USD
CY2022Q1	us-gaap	Notes Payable NotesPayable	445500000	USD
CY2021Q4	us-gaap	Notes Payable NotesPayable	457100000	USD
CY2022Q1	us-gaap	Other Borrowings OtherBorrowings	833300000	USD
CY2021Q4	us-gaap	Other Borrowings OtherBorrowings	1501900000	USD
CY2022Q1	us-gaap	Federal Funds Purchased FederalFundsPurchased	0	USD
CY2021Q4	us-gaap	Federal Funds Purchased FederalFundsPurchased	675000000	USD
CY2022Q1	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due Within One Year Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate	0	USD
CY2022Q1	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	18000000	USD
CY2021Q4	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	16600000	USD
CY2022Q1	us-gaap	Other Short Term Borrowings OtherShortTermBorrowings	52300000	USD
CY2021Q4	us-gaap	Other Short Term Borrowings OtherShortTermBorrowings	35300000	USD
CY2022Q1	us-gaap	Senior Notes SeniorNotes	317500000	USD
CY2021Q4	us-gaap	Notes Payable NotesPayable	457100000	USD
CY2022Q1	us-gaap	Subordinated Long Term Debt SubordinatedLongTermDebt	815500000	USD
CY2021Q4	us-gaap	Subordinated Long Term Debt SubordinatedLongTermDebt	815100000	USD
CY2022Q1	wal	Numberof Statutory Business Trusts Formedor Acquired NumberofStatutoryBusinessTrustsFormedorAcquired	8	Trust
CY2022Q1	us-gaap	Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust	77800000	USD
CY2021Q4	us-gaap	Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust	80700000	USD
CY2022Q1	us-gaap	Preferred Stock Dividends Per Share Cash Paid PreferredStockDividendsPerShareCashPaid	0.27
CY2022Q1	us-gaap	Stock Issued During Period Shares New Issues StockIssuedDuringPeriodSharesNewIssues	1300000	shares
CY2022Q1	us-gaap	Shares Issued Price Per Share SharesIssuedPricePerShare	86.78
CY2022Q1	us-gaap	Adjustments To Additional Paid In Capital Stock Issued Issuance Costs AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts	700000	USD
CY2021Q1	us-gaap	Stock Issued During Period Shares New Issues StockIssuedDuringPeriodSharesNewIssues	2300000	shares
CY2021Q1	us-gaap	Shares Issued Price Per Share SharesIssuedPricePerShare	91.00
CY2021Q1	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	209200000	USD
CY2022Q1	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.35
CY2021Q1	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.25
CY2022Q1	us-gaap	Shares Paid For Tax Withholding For Share Based Compensation SharesPaidForTaxWithholdingForShareBasedCompensation	185534	shares
CY2022Q1	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	93.51
CY2021Q1	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	83.56
CY2021Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	15700000	USD
CY2022Q1	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	-245700000	USD
CY2022Q1	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	5100000	USD
CY2022Q1	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-250800000	USD
CY2022Q1	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-235100000	USD
CY2020Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	92300000	USD
CY2021Q1	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	-72300000	USD
CY2021Q1	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	100000	USD
CY2021Q1	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-72400000	USD
CY2021Q1	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	19900000	USD
CY2022Q1	us-gaap	Hedged Asset Fair Value Hedge HedgedAssetFairValueHedge	474000000.0	USD
CY2022Q1	us-gaap	Hedged Asset Fair Value Hedge Cumulative Increase Decrease HedgedAssetFairValueHedgeCumulativeIncreaseDecrease	20700000	USD
CY2021Q4	us-gaap	Hedged Asset Fair Value Hedge HedgedAssetFairValueHedge	1390700000	USD
CY2021Q4	us-gaap	Hedged Asset Fair Value Hedge Cumulative Increase Decrease HedgedAssetFairValueHedgeCumulativeIncreaseDecrease	38500000	USD
CY2022Q1	us-gaap	Derivative Asset Collateral Obligation To Return Cash Offset DerivativeAssetCollateralObligationToReturnCashOffset	100000	USD
CY2022Q1	us-gaap	Derivative Asset Collateral Obligation To Return Cash Offset DerivativeAssetCollateralObligationToReturnCashOffset	100000	USD
CY2021Q4	us-gaap	Derivative Asset Collateral Obligation To Return Cash Offset DerivativeAssetCollateralObligationToReturnCashOffset	1200000	USD
CY2021Q4	us-gaap	Derivative Asset Collateral Obligation To Return Cash Offset DerivativeAssetCollateralObligationToReturnCashOffset	1200000	USD
CY2022Q1	wal	Derivative Netting Adjustments Assets DerivativeNettingAdjustmentsAssets	-130000000.0	USD
CY2022Q1	wal	Derivative Netting Adjustments Assets DerivativeNettingAdjustmentsAssets	-130000000.0	USD
CY2021Q4	wal	Derivative Netting Adjustments Assets DerivativeNettingAdjustmentsAssets	-28400000	USD
CY2021Q4	wal	Derivative Netting Adjustments Assets DerivativeNettingAdjustmentsAssets	-28400000	USD
CY2022Q1	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	154200000	USD
CY2022Q1	wal	Derivative Netting Adjustments Assets DerivativeNettingAdjustmentsAssets	-130000000.0	USD
CY2022Q1	us-gaap	Derivative Fair Value Of Derivative Asset Amount Offset Against Collateral DerivativeFairValueOfDerivativeAssetAmountOffsetAgainstCollateral	24200000	USD
CY2021Q4	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	38400000	USD
CY2021Q4	wal	Derivative Netting Adjustments Assets DerivativeNettingAdjustmentsAssets	-28400000	USD
CY2021Q4	us-gaap	Derivative Fair Value Of Derivative Asset Amount Offset Against Collateral DerivativeFairValueOfDerivativeAssetAmountOffsetAgainstCollateral	10000000.0	USD
CY2021Q1	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	7900000	USD
CY2021Q1	wal	Derivative Netting Adjustments Assets DerivativeNettingAdjustmentsAssets	0	USD
CY2021Q1	us-gaap	Derivative Fair Value Of Derivative Asset Amount Offset Against Collateral DerivativeFairValueOfDerivativeAssetAmountOffsetAgainstCollateral	7900000	USD
CY2022Q1	us-gaap	Derivative Liability Collateral Right To Reclaim Cash Offset DerivativeLiabilityCollateralRightToReclaimCashOffset	64900000	USD
CY2022Q1	us-gaap	Derivative Liability Collateral Right To Reclaim Cash Offset DerivativeLiabilityCollateralRightToReclaimCashOffset	64900000	USD
CY2021Q4	us-gaap	Derivative Liability Collateral Right To Reclaim Cash Offset DerivativeLiabilityCollateralRightToReclaimCashOffset	6500000	USD
CY2021Q4	us-gaap	Derivative Liability Collateral Right To Reclaim Cash Offset DerivativeLiabilityCollateralRightToReclaimCashOffset	6500000	USD
CY2022Q1	wal	Derivative Netting Adjustments Liabilities DerivativeNettingAdjustmentsLiabilities	130000000.0	USD
CY2022Q1	wal	Derivative Netting Adjustments Liabilities DerivativeNettingAdjustmentsLiabilities	130000000.0	USD
CY2021Q4	wal	Derivative Netting Adjustments Liabilities DerivativeNettingAdjustmentsLiabilities	28400000	USD
CY2021Q4	wal	Derivative Netting Adjustments Liabilities DerivativeNettingAdjustmentsLiabilities	28400000	USD
CY2022Q1	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	158200000	USD
CY2022Q1	wal	Derivative Netting Adjustments Liabilities DerivativeNettingAdjustmentsLiabilities	130000000.0	USD
CY2022Q1	us-gaap	Derivative Fair Value Of Derivative Liability Amount Offset Against Collateral DerivativeFairValueOfDerivativeLiabilityAmountOffsetAgainstCollateral	28200000	USD
CY2021Q4	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	96300000	USD
CY2021Q4	wal	Derivative Netting Adjustments Liabilities DerivativeNettingAdjustmentsLiabilities	28400000	USD
CY2021Q4	us-gaap	Derivative Fair Value Of Derivative Liability Amount Offset Against Collateral DerivativeFairValueOfDerivativeLiabilityAmountOffsetAgainstCollateral	67900000	USD
CY2021Q1	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	57700000	USD
CY2021Q1	wal	Derivative Netting Adjustments Liabilities DerivativeNettingAdjustmentsLiabilities	0	USD
CY2021Q1	us-gaap	Derivative Fair Value Of Derivative Liability Amount Offset Against Collateral DerivativeFairValueOfDerivativeLiabilityAmountOffsetAgainstCollateral	57700000	USD
CY2022Q1	us-gaap	Derivative Asset Not Subject To Master Netting Arrangement DerivativeAssetNotSubjectToMasterNettingArrangement	7500000	USD
CY2022Q1	us-gaap	Derivative Asset Not Subject To Master Netting Arrangement DerivativeAssetNotSubjectToMasterNettingArrangement	7500000	USD
CY2021Q4	us-gaap	Derivative Asset Not Subject To Master Netting Arrangement DerivativeAssetNotSubjectToMasterNettingArrangement	11800000	USD
CY2021Q4	us-gaap	Derivative Asset Not Subject To Master Netting Arrangement DerivativeAssetNotSubjectToMasterNettingArrangement	11800000	USD
CY2021Q1	us-gaap	Derivative Asset Not Subject To Master Netting Arrangement DerivativeAssetNotSubjectToMasterNettingArrangement	1200000	USD
CY2021Q1	us-gaap	Derivative Asset Not Subject To Master Netting Arrangement DerivativeAssetNotSubjectToMasterNettingArrangement	1200000	USD
CY2022Q1	us-gaap	Derivative Liability Not Subject To Master Netting Arrangement DerivativeLiabilityNotSubjectToMasterNettingArrangement	19600000	USD
CY2022Q1	us-gaap	Derivative Liability Not Subject To Master Netting Arrangement DerivativeLiabilityNotSubjectToMasterNettingArrangement	19600000	USD
CY2021Q4	us-gaap	Derivative Liability Not Subject To Master Netting Arrangement DerivativeLiabilityNotSubjectToMasterNettingArrangement	3500000	USD
CY2021Q4	us-gaap	Derivative Liability Not Subject To Master Netting Arrangement DerivativeLiabilityNotSubjectToMasterNettingArrangement	3500000	USD
CY2021Q1	us-gaap	Derivative Liability Not Subject To Master Netting Arrangement DerivativeLiabilityNotSubjectToMasterNettingArrangement	900000	USD
CY2021Q1	us-gaap	Derivative Liability Not Subject To Master Netting Arrangement DerivativeLiabilityNotSubjectToMasterNettingArrangement	900000	USD
CY2022Q1	us-gaap	Derivative Asset Fair Value Gross Asset Including Not Subject To Master Netting Arrangement DerivativeAssetFairValueGrossAssetIncludingNotSubjectToMasterNettingArrangement	161700000	USD
CY2022Q1	wal	Derivative Netting Adjustments Assets DerivativeNettingAdjustmentsAssets	-130000000.0	USD
CY2022Q1	us-gaap	Derivative Asset Fair Value Offset Against Collateral Net Of Not Subject To Master Netting Arrangement Policy Election DerivativeAssetFairValueOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection	31700000	USD
CY2021Q4	us-gaap	Derivative Asset Fair Value Gross Asset Including Not Subject To Master Netting Arrangement DerivativeAssetFairValueGrossAssetIncludingNotSubjectToMasterNettingArrangement	50200000	USD
CY2021Q4	wal	Derivative Netting Adjustments Assets DerivativeNettingAdjustmentsAssets	-28400000	USD
CY2021Q4	us-gaap	Derivative Asset Fair Value Offset Against Collateral Net Of Not Subject To Master Netting Arrangement Policy Election DerivativeAssetFairValueOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection	21800000	USD
CY2021Q1	us-gaap	Derivative Asset Fair Value Gross Asset Including Not Subject To Master Netting Arrangement DerivativeAssetFairValueGrossAssetIncludingNotSubjectToMasterNettingArrangement	9100000	USD
CY2021Q1	wal	Derivative Netting Adjustments Assets DerivativeNettingAdjustmentsAssets	0	USD
CY2021Q1	us-gaap	Derivative Asset Fair Value Offset Against Collateral Net Of Not Subject To Master Netting Arrangement Policy Election DerivativeAssetFairValueOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection	9100000	USD
CY2022Q1	us-gaap	Derivative Liability Fair Value Gross Liability Including Not Subject To Master Netting Arrangement DerivativeLiabilityFairValueGrossLiabilityIncludingNotSubjectToMasterNettingArrangement	177800000	USD
CY2022Q1	wal	Derivative Netting Adjustments Liabilities DerivativeNettingAdjustmentsLiabilities	130000000.0	USD
CY2022Q1	us-gaap	Derivative Liability Fair Value Offset Against Collateral Net Of Not Subject To Master Netting Arrangement Policy Election DerivativeLiabilityFairValueOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection	47800000	USD
CY2021Q4	us-gaap	Derivative Liability Fair Value Gross Liability Including Not Subject To Master Netting Arrangement DerivativeLiabilityFairValueGrossLiabilityIncludingNotSubjectToMasterNettingArrangement	99800000	USD
CY2021Q4	wal	Derivative Netting Adjustments Liabilities DerivativeNettingAdjustmentsLiabilities	28400000	USD
CY2021Q4	us-gaap	Derivative Liability Fair Value Offset Against Collateral Net Of Not Subject To Master Netting Arrangement Policy Election DerivativeLiabilityFairValueOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection	71400000	USD
CY2021Q1	us-gaap	Derivative Liability Fair Value Gross Liability Including Not Subject To Master Netting Arrangement DerivativeLiabilityFairValueGrossLiabilityIncludingNotSubjectToMasterNettingArrangement	58600000	USD
CY2021Q1	wal	Derivative Netting Adjustments Liabilities DerivativeNettingAdjustmentsLiabilities	0	USD
CY2021Q1	us-gaap	Derivative Liability Fair Value Offset Against Collateral Net Of Not Subject To Master Netting Arrangement Policy Election DerivativeLiabilityFairValueOffsetAgainstCollateralNetOfNotSubjectToMasterNettingArrangementPolicyElection	58600000	USD
CY2022Q1	us-gaap	Derivative Liability Fair Value Of Collateral DerivativeLiabilityFairValueOfCollateral	45000000	USD
CY2021Q4	us-gaap	Derivative Liability Fair Value Of Collateral DerivativeLiabilityFairValueOfCollateral	67100000	USD
CY2021Q1	us-gaap	Derivative Liability Fair Value Of Collateral DerivativeLiabilityFairValueOfCollateral	93200000	USD
CY2022Q1	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	106000000.0	shares
CY2021Q1	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	100800000	shares
CY2022Q1	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	600000	shares
CY2021Q1	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	600000	shares
CY2022Q1	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	106600000	shares
CY2021Q1	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	101400000	shares
CY2022Q1	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	236900000	USD
CY2021Q1	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	192500000	USD
CY2022Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.23
CY2021Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.91
CY2022Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.22
CY2021Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.90
CY2021Q1	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
CY2022Q1	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
CY2022Q1	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.195
CY2021Q1	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.179
CY2022Q1	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	67600000	USD
CY2022Q1	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	46700000	USD
CY2021Q4	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	20900000	USD
CY2022Q1	us-gaap	Deferred Income Tax Assets Net DeferredIncomeTaxAssetsNet	67600000	USD
CY2022Q1	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	0	USD
CY2021Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	0	USD
CY2022Q1	us-gaap	Amortization Method Qualified Affordable Housing Project Investments AmortizationMethodQualifiedAffordableHousingProjectInvestments	729900000	USD
CY2021Q4	us-gaap	Amortization Method Qualified Affordable Housing Project Investments AmortizationMethodQualifiedAffordableHousingProjectInvestments	631300000	USD
CY2022Q1	us-gaap	Investment Related Liabilities InvestmentRelatedLiabilities	445900000	USD
CY2021Q4	us-gaap	Investment Related Liabilities InvestmentRelatedLiabilities	360800000	USD
CY2022Q1	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	13400000	USD
CY2021Q1	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	15500000	USD
CY2022Q1	us-gaap	Line Of Credit Facility Expiration Period LineOfCreditFacilityExpirationPeriod	P1Y
CY2022Q1	us-gaap	Fair Value Disclosure Offbalance Sheet Risks Face Amount Liability FairValueDisclosureOffbalanceSheetRisksFaceAmountLiability	15405800000	USD
CY2021Q4	us-gaap	Fair Value Disclosure Offbalance Sheet Risks Face Amount Liability FairValueDisclosureOffbalanceSheetRisksFaceAmountLiability	13900700000	USD
CY2022Q1	wal	Maximum Loan To Value Ratio MaximumLoanToValueRatio	0.75
CY2022Q1	wal	Percentage Of Commercial Real Estate Loans Occupied By Owners PercentageOfCommercialRealEstateLoansOccupiedByOwners	0.21
CY2021Q4	wal	Percentage Of Commercial Real Estate Loans Occupied By Owners PercentageOfCommercialRealEstateLoansOccupiedByOwners	0.23
CY2022Q1	us-gaap	Lease Cost LeaseCost	5900000	USD
CY2021Q1	us-gaap	Lease Cost LeaseCost	3700000	USD
CY2022Q1	wal	Lesseeoperatingleaseothercost Lesseeoperatingleaseothercost	1100000	USD
CY2021Q1	wal	Lesseeoperatingleaseothercost Lesseeoperatingleaseothercost	1000000	USD
CY2022Q1	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	-2200000	USD
CY2021Q1	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	-300000	USD
CY2022Q1	us-gaap	Fair Value Liabilities Measured On Recurring Basis Subordinated Debt Obligations FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations	64500000	USD
CY2022Q1	us-gaap	Hedged Asset Fair Value Hedge Cumulative Increase Decrease HedgedAssetFairValueHedgeCumulativeIncreaseDecrease	20700000	USD
CY2021Q4	us-gaap	Fair Value Liabilities Measured On Recurring Basis Subordinated Debt Obligations FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations	67400000	USD
CY2021Q4	us-gaap	Hedged Asset Fair Value Hedge Cumulative Increase Decrease HedgedAssetFairValueHedgeCumulativeIncreaseDecrease	38500000	USD
CY2022Q1	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	-2200000	USD
CY2021Q1	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	-300000	USD
CY2022Q1	wal	Fair Value Option Loans Held As Assets Current Through89 Days FairValueOptionLoansHeldAsAssetsCurrentThrough89Days	2946400000	USD
CY2022Q1	wal	Fair Value Option Loans Held As Assets Upb Current Through89 Days FairValueOptionLoansHeldAsAssetsUPBCurrentThrough89Days	2936900000	USD
CY2022Q1	wal	Fair Value Option Loans Held As Assets Current Through89 Days Aggregate Difference FairValueOptionLoansHeldAsAssetsCurrentThrough89DaysAggregateDifference	9500000	USD
CY2021Q4	wal	Fair Value Option Loans Held As Assets Current Through89 Days FairValueOptionLoansHeldAsAssetsCurrentThrough89Days	3937500000	USD
CY2021Q4	wal	Fair Value Option Loans Held As Assets Upb Current Through89 Days FairValueOptionLoansHeldAsAssetsUPBCurrentThrough89Days	3807300000	USD
CY2021Q4	wal	Fair Value Option Loans Held As Assets Current Through89 Days Aggregate Difference FairValueOptionLoansHeldAsAssetsCurrentThrough89DaysAggregateDifference	130200000	USD
CY2022Q1	us-gaap	Fair Value Option Loans Held As Assets90 Days Or More Past Due FairValueOptionLoansHeldAsAssets90DaysOrMorePastDue	2000000.0	USD
CY2022Q1	wal	Fair Value Option Loans Held As Assets Upb90 Days Or More Past Due FairValueOptionLoansHeldAsAssetsUPB90DaysOrMorePastDue	2100000	USD
CY2022Q1	us-gaap	Fair Value Option Loans Held As Assets90 Days Or More Past Due Aggregate Difference FairValueOptionLoansHeldAsAssets90DaysOrMorePastDueAggregateDifference	-100000	USD
CY2021Q4	us-gaap	Fair Value Option Loans Held As Assets90 Days Or More Past Due FairValueOptionLoansHeldAsAssets90DaysOrMorePastDue	2200000	USD
CY2021Q4	wal	Fair Value Option Loans Held As Assets Upb90 Days Or More Past Due FairValueOptionLoansHeldAsAssetsUPB90DaysOrMorePastDue	2200000	USD
CY2021Q4	us-gaap	Fair Value Option Loans Held As Assets90 Days Or More Past Due Aggregate Difference FairValueOptionLoansHeldAsAssets90DaysOrMorePastDueAggregateDifference	0	USD
CY2022Q1	wal	Fair Value Option Loans Held As Assets FairValueOptionLoansHeldAsAssets	2948400000	USD
CY2022Q1	us-gaap	Fair Value Option Loans Held As Assets Aggregate Difference FairValueOptionLoansHeldAsAssetsAggregateDifference	9400000	USD
CY2021Q4	wal	Fair Value Option Loans Held As Assets FairValueOptionLoansHeldAsAssets	3939700000	USD
CY2021Q4	us-gaap	Fair Value Option Loans Held As Assets Aggregate Difference FairValueOptionLoansHeldAsAssetsAggregateDifference	130200000	USD
CY2022Q1	wal	Cash Cash Equivalentsand Investment Securities CashCashEquivalentsandInvestmentSecurities	10878900000	USD
CY2022Q1	us-gaap	Loans Receivable Held For Sale Amount LoansReceivableHeldForSaleAmount	4761600000	USD
CY2022Q1	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	41119100000	USD
CY2022Q1	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	257600000	USD
CY2022Q1	us-gaap	Loans And Leases Receivable Net Reported Amount LoansAndLeasesReceivableNetReportedAmount	40861500000	USD
CY2021Q4	us-gaap	Stockholders Equity StockholdersEquity	4962600000	USD
CY2022Q1	us-gaap	Other Foreclosed Assets OtherForeclosedAssets	11700000	USD
CY2022Q1	us-gaap	Intangible Assets Net Including Goodwill IntangibleAssetsNetIncludingGoodwill	698200000	USD
CY2022Q1	wal	Other Assets Segment OtherAssetsSegment	3364200000	USD
CY2022Q1	us-gaap	Assets Assets	60576100000	USD
CY2022Q1	us-gaap	Deposits Deposits	52159500000	USD
CY2022Q1	wal	Borrowingsand Qualifying Debt BorrowingsandQualifyingDebt	1726600000	USD
CY2022Q1	wal	Other Liabilities Segment OtherLiabilitiesSegment	1678400000	USD
CY2022Q1	us-gaap	Liabilities Liabilities	55564500000	USD
CY2022Q1	us-gaap	Stockholders Equity StockholdersEquity	5011600000	USD
CY2022Q1	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	60576100000	USD
CY2022Q1	wal	Excess Funds Providedby Usedin Segment Basis ExcessFundsProvidedbyUsedinSegmentBasis	0	USD
CY2022Q1	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	449500000	USD
CY2022Q1	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	9000000.0	USD
CY2022Q1	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	440500000	USD
CY2022Q1	us-gaap	Noninterest Income NoninterestIncome	106300000	USD
CY2022Q1	us-gaap	Noninterest Expense NoninterestExpense	248600000	USD
CY2022Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	298200000	USD
CY2022Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	58100000	USD
CY2022Q1	us-gaap	Net Income Loss NetIncomeLoss	240100000	USD
CY2021Q4	wal	Cash Cash Equivalentsand Investment Securities CashCashEquivalentsandInvestmentSecurities	8057300000	USD
CY2021Q4	us-gaap	Loans Receivable Held For Sale Amount LoansReceivableHeldForSaleAmount	5635100000	USD
CY2021Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	39075400000	USD
CY2021Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	252500000	USD
CY2021Q4	us-gaap	Loans And Leases Receivable Net Reported Amount LoansAndLeasesReceivableNetReportedAmount	38822900000	USD
CY2021Q4	us-gaap	Other Foreclosed Assets OtherForeclosedAssets	11700000	USD
CY2021Q4	us-gaap	Intangible Assets Net Including Goodwill IntangibleAssetsNetIncludingGoodwill	634800000	USD
CY2021Q4	wal	Other Assets Segment OtherAssetsSegment	2820800000	USD
CY2021Q4	us-gaap	Assets Assets	55982600000	USD
CY2021Q4	us-gaap	Deposits Deposits	47612000000	USD
CY2021Q4	wal	Borrowingsand Qualifying Debt BorrowingsandQualifyingDebt	2381100000	USD
CY2021Q4	wal	Other Liabilities Segment OtherLiabilitiesSegment	1026900000	USD
CY2021Q4	us-gaap	Liabilities Liabilities	51020000000	USD
CY2021Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	55982600000	USD
CY2021Q4	wal	Excess Funds Providedby Usedin Segment Basis ExcessFundsProvidedbyUsedinSegmentBasis	0	USD
CY2021Q1	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	317300000	USD
CY2021Q1	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	32400000	USD
CY2021Q1	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	349700000	USD
CY2021Q1	us-gaap	Noninterest Income NoninterestIncome	19700000	USD
CY2021Q1	us-gaap	Noninterest Expense NoninterestExpense	135000000.0	USD
CY2021Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	234400000	USD
CY2021Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	41900000	USD
CY2021Q1	us-gaap	Net Income Loss NetIncomeLoss	192500000	USD
CY2022Q1	wal	Revenue From Contracts With Customers RevenueFromContractsWithCustomers	14400000	USD
CY2021Q1	wal	Revenue From Contracts With Customers RevenueFromContractsWithCustomers	9200000	USD

Files In Submission

Name	View Source	Status
0001212545-22-000109-index-headers.html	Edgar Link	pending
0001212545-22-000109-index.html	Edgar Link	pending
0001212545-22-000109.txt	Edgar Link	pending
0001212545-22-000109-xbrl.zip	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
Financial_Report.xlsx	Edgar Link	pending
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wal-20220331.htm	Edgar Link	pending
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wal-20220331_cal.xml	Edgar Link	unprocessable
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wal-20220331_htm.xml	Edgar Link	completed
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walex3113312022.htm	Edgar Link	pending
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$WAL
WESTERN ALLIANCE BANCORPORATION Stock $wal

2022 Q1 Form 10-Q Financial Statement

#000121254522000109 Filed on April 29, 2022

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WAL WESTERN ALLIANCE BANCORPORATION Stock $wal

2022 Q1 Form 10-Q Financial Statement

#000121254522000109 Filed on April 29, 2022

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WAL
WESTERN ALLIANCE BANCORPORATION Stock $wal