$WAL
WESTERN ALLIANCE BANCORPORATION Stock $wal

$wal Overview Financials Valuation SEC Filings Company Website

2019 Q2 Form 10-Q Financial Statement

#000121254519000108 Filed on August 01, 2019

Income Statement

Concept	2019 Q2	2018 Q2
Revenue	$302.9M	$251.6M
YoY Change	20.39%	21.57%
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	$4.600M	$3.400M
YoY Change	35.29%	6.25%
% of Gross Profit
Operating Expenses
YoY Change
Operating Profit
YoY Change
Interest Expense	$48.20M	$27.49M
YoY Change	75.31%	93.48%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	$147.8M	$130.0M
YoY Change	13.69%	16.15%
Income Tax	$24.80M	$25.33M
% Of Pretax Income	16.78%	19.48%
Net Earnings	$123.0M	$104.7M
YoY Change	17.5%	30.91%
Net Earnings / Revenue	40.61%	41.6%
Basic Earnings Per Share	$1.19	$1.00
Diluted Earnings Per Share	$1.19	$0.99
COMMON SHARES
Basic Shares Outstanding	103.0M shares	104.7M shares
Diluted Shares Outstanding	103.5M shares	105.4M shares

Balance Sheet

Concept	2019 Q2	2018 Q2
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$1.068B	$506.8M
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	$123.1M	$115.4M
YoY Change	6.68%	-4.22%
Goodwill	$289.9M	$289.9M
YoY Change	0.0%	0.0%
Intangibles	$8.486M	$10.06M
YoY Change	-15.61%	-14.42%
Long-Term Investments	$115.0M	$143.0M
YoY Change	-19.58%
Other Assets	$9.000M	$39.00M
YoY Change	-76.92%	-55.68%
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$25.31B	$21.37B
YoY Change	18.47%	13.39%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses	$76.00M
YoY Change
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$75.00M
YoY Change	-100.0%
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$76.00M	$18.00M
YoY Change	322.22%	-45.45%
LONG-TERM LIABILITIES
Long-Term Debt	$387.0M	$436.0M
YoY Change	-11.24%	16.27%
Other Long-Term Liabilities	$546.0M	$434.0M
YoY Change	25.81%	25.07%
Total Long-Term Liabilities	$933.0M	$870.0M
YoY Change	7.24%	20.5%
TOTAL LIABILITIES
Total Short-Term Liabilities	$76.00M	$18.00M
Total Long-Term Liabilities	$933.0M	$870.0M
Total Liabilities	$22.46B	$18.98B
YoY Change	18.38%	13.04%
SHAREHOLDERS EQUITY
Retained Earnings	$1.514B	$1.055B
YoY Change	43.49%	56.13%
Common Stock	$10.00K	$10.00K
YoY Change	0.0%	0.0%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$61.13M	$50.97M
YoY Change	19.94%	39.07%
Treasury Stock Shares
Shareholders Equity	$2.851B	$2.392B
YoY Change
Total Liabilities & Shareholders Equity	$25.31B	$21.37B
YoY Change	18.47%	13.39%

Cashflow Statement

Concept	2019 Q2	2018 Q2
OPERATING ACTIVITIES
Net Income	$123.0M	$104.7M
YoY Change	17.5%	30.91%
Depreciation, Depletion And Amortization	$4.600M	$3.400M
YoY Change	35.29%	6.25%
Cash From Operating Activities	$179.0M	$159.1M
YoY Change	12.51%	82.04%
INVESTING ACTIVITIES
Capital Expenditures	-$6.000M	-$1.200M
YoY Change	400.0%	-52.0%
Acquisitions
YoY Change
Other Investing Activities	-$1.087B	-$590.5M
YoY Change	84.03%	-25.97%
Cash From Investing Activities	-$1.093B	-$591.7M
YoY Change	84.67%	-26.06%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	1.196B	500.1M
YoY Change	139.11%	-25.62%
NET CHANGE
Cash From Operating Activities	179.0M	159.1M
Cash From Investing Activities	-1.093B	-591.7M
Cash From Financing Activities	1.196B	500.1M
Net Change In Cash	282.1M	67.50M
YoY Change	317.93%	-267.08%
FREE CASH FLOW
Cash From Operating Activities	$179.0M	$159.1M
Capital Expenditures	-$6.000M	-$1.200M
Free Cash Flow	$185.0M	$160.3M
YoY Change	15.41%	78.31%

Facts In Submission

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	dei	Amendment Flag AmendmentFlag	false
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q2
	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2019
	dei	Entity Central Index Key EntityCentralIndexKey	0001212545
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	dei	Document Quarterly Report DocumentQuarterlyReport	true
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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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CY2019Q2	wal	Incomefrom Equity Investments IncomefromEquityInvestments	868000	USD
CY2018Q2	wal	Incomefrom Equity Investments IncomefromEquityInvestments	2517000	USD
	wal	Incomefrom Equity Investments IncomefromEquityInvestments	2877000	USD
	wal	Incomefrom Equity Investments IncomefromEquityInvestments	3977000	USD
CY2018Q2	wal	Lendingrelatedfees Lendingrelatedfees	1047000	USD
	wal	Lendingrelatedfees Lendingrelatedfees	804000	USD
	wal	Lendingrelatedfees Lendingrelatedfees	2025000	USD
CY2019Q2	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	1572000	USD
CY2018Q2	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	-685000	USD
	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	4406000	USD
	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	-1759000	USD
CY2019Q2	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	1653000	USD
CY2018Q2	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	512000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	2640000	USD
	us-gaap	Noninterest Income Other Operating Income NoninterestIncomeOtherOperatingIncome	944000	USD
CY2019Q2	us-gaap	Noninterest Income NoninterestIncome	14218000	USD
CY2018Q2	us-gaap	Noninterest Income NoninterestIncome	13444000	USD
	us-gaap	Noninterest Income NoninterestIncome	29628000	USD
	us-gaap	Noninterest Income NoninterestIncome	25087000	USD
CY2019Q2	us-gaap	Labor And Related Expense LaborAndRelatedExpense	65794000	USD
CY2018Q2	us-gaap	Labor And Related Expense LaborAndRelatedExpense	61785000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	134350000	USD
	us-gaap	Labor And Related Expense LaborAndRelatedExpense	123918000	USD
CY2019Q2	wal	Legal Professional And Director Fees LegalProfessionalAndDirectorFees	11105000	USD
CY2018Q2	wal	Legal Professional And Director Fees LegalProfessionalAndDirectorFees	7946000	USD
	wal	Legal Professional And Director Fees LegalProfessionalAndDirectorFees	18637000	USD
	wal	Legal Professional And Director Fees LegalProfessionalAndDirectorFees	13949000	USD
CY2019Q2	us-gaap	Occupancy Net OccupancyNet	7761000	USD
CY2018Q2	us-gaap	Occupancy Net OccupancyNet	7401000	USD
	us-gaap	Occupancy Net OccupancyNet	15988000	USD
	us-gaap	Occupancy Net OccupancyNet	14265000	USD
CY2019Q2	wal	Non Interest Expense Deposit Costs NonInterestExpenseDepositCosts	7669000	USD
CY2018Q2	wal	Non Interest Expense Deposit Costs NonInterestExpenseDepositCosts	4114000	USD
	wal	Non Interest Expense Deposit Costs NonInterestExpenseDepositCosts	13393000	USD
	wal	Non Interest Expense Deposit Costs NonInterestExpenseDepositCosts	7040000	USD
CY2019Q2	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	6793000	USD
CY2018Q2	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	5586000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	13468000	USD
	us-gaap	Information Technology And Data Processing InformationTechnologyAndDataProcessing	10793000	USD
CY2019Q2	us-gaap	General Insurance Expense GeneralInsuranceExpense	2811000	USD
CY2018Q2	us-gaap	General Insurance Expense GeneralInsuranceExpense	3885000	USD
	us-gaap	General Insurance Expense GeneralInsuranceExpense	5620000	USD
	us-gaap	General Insurance Expense GeneralInsuranceExpense	7754000	USD
CY2019Q2	wal	Loan And Repossessed Asset Expense LoanAndRepossessedAssetExpense	1460000	USD
CY2018Q2	wal	Loan And Repossessed Asset Expense LoanAndRepossessedAssetExpense	1017000	USD
	wal	Loan And Repossessed Asset Expense LoanAndRepossessedAssetExpense	3466000	USD
	wal	Loan And Repossessed Asset Expense LoanAndRepossessedAssetExpense	1600000	USD
CY2019Q2	us-gaap	Business Development BusinessDevelopment	1444000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	294018000	USD
CY2018Q2	us-gaap	Business Development BusinessDevelopment	1414000	USD
	us-gaap	Business Development BusinessDevelopment	3529000	USD
	us-gaap	Business Development BusinessDevelopment	3142000	USD
CY2019Q2	us-gaap	Marketing Expense MarketingExpense	1057000	USD
CY2018Q2	us-gaap	Marketing Expense MarketingExpense	1146000	USD
	us-gaap	Marketing Expense MarketingExpense	1798000	USD
	us-gaap	Marketing Expense MarketingExpense	1742000	USD
CY2019Q2	wal	Cardexpense Cardexpense	710000	USD
CY2018Q2	wal	Cardexpense Cardexpense	1081000	USD
	wal	Cardexpense Cardexpense	1344000	USD
	wal	Cardexpense Cardexpense	2023000	USD
CY2019Q2	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	387000	USD
CY2018Q2	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	399000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	774000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	797000	USD
CY2019Q2	wal	Net Loss Gain On Sales Valuations Of Repossessed Assets And Bank Premises Net NetLossGainOnSalesValuationsOfRepossessedAssetsAndBankPremisesNet	-620000	USD
CY2018Q2	wal	Net Loss Gain On Sales Valuations Of Repossessed Assets And Bank Premises Net NetLossGainOnSalesValuationsOfRepossessedAssetsAndBankPremisesNet	-179000	USD
	wal	Net Loss Gain On Sales Valuations Of Repossessed Assets And Bank Premises Net NetLossGainOnSalesValuationsOfRepossessedAssetsAndBankPremisesNet	-523000	USD
	wal	Net Loss Gain On Sales Valuations Of Repossessed Assets And Bank Premises Net NetLossGainOnSalesValuationsOfRepossessedAssetsAndBankPremisesNet	-1407000	USD
CY2019Q2	us-gaap	Other Noninterest Expense OtherNoninterestExpense	7842000	USD
CY2018Q2	us-gaap	Other Noninterest Expense OtherNoninterestExpense	6953000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	15283000	USD
	us-gaap	Other Noninterest Expense OtherNoninterestExpense	15081000	USD
CY2019Q2	us-gaap	Noninterest Expense NoninterestExpense	114213000	USD
CY2018Q2	us-gaap	Noninterest Expense NoninterestExpense	102548000	USD
	us-gaap	Noninterest Expense NoninterestExpense	227127000	USD
	us-gaap	Noninterest Expense NoninterestExpense	200697000	USD
CY2019Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	147686000	USD
CY2018Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	130004000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	251718000	USD
CY2019Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	24750000	USD
CY2018Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	25325000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	50286000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	46139000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	122936000	USD
CY2018Q2	us-gaap	Net Income Loss NetIncomeLoss	104679000	USD
	us-gaap	Net Income Loss NetIncomeLoss	243732000	USD
	us-gaap	Net Income Loss NetIncomeLoss	205579000	USD
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.19
CY2018Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.00
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.35
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.97
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.19
CY2018Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.99
	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	-7262000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-49303000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	17000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	35923000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-10389000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	67300000	USD
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.34
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.95
CY2019Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	103019000	shares
CY2018Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	104691000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	103523000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	104611000	shares
CY2019Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	103501000	shares
CY2018Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	105420000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	103985000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	105372000	shares
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	122936000	USD
CY2018Q2	us-gaap	Net Income Loss NetIncomeLoss	104679000	USD
	us-gaap	Net Income Loss NetIncomeLoss	243732000	USD
	us-gaap	Net Income Loss NetIncomeLoss	205579000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	12000	USD
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	35000	USD
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	23000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	-1334000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	748000	USD
	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	2214000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	34572000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-9653000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	60003000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-47112000	USD
CY2019Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	157508000	USD
CY2018Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	95026000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	303735000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	158467000	USD
CY2018Q1	us-gaap	Stockholders Equity StockholdersEquity	2293763000	USD
CY2018Q2	us-gaap	Net Income Loss NetIncomeLoss	104679000	USD
CY2018Q2	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	319000	USD
CY2018Q2	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	7078000	USD
CY2018Q2	us-gaap	Restricted Stock Award Forfeitures RestrictedStockAwardForfeitures	4502000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-9653000	USD
CY2018Q2	us-gaap	Stockholders Equity StockholdersEquity	2391684000	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 Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	0	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
CY2017Q4	us-gaap	Stockholders Equity StockholdersEquity	2229698000	USD
CY2018Q1	us-gaap	Stockholders Equity StockholdersEquity	2229698000	USD
	us-gaap	Net Income Loss NetIncomeLoss	205579000	USD
	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	534000	USD
	us-gaap	Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures	13783000	USD
	us-gaap	Restricted Stock Award Forfeitures RestrictedStockAwardForfeitures	10798000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-47112000	USD
CY2018Q2	us-gaap	Stockholders Equity StockholdersEquity	2391684000	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
	us-gaap	Net Income Loss NetIncomeLoss	243732000	USD
	us-gaap	Net Income Loss NetIncomeLoss	205579000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	10500000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	11000000	USD
	us-gaap	Depreciation And Amortization DepreciationAndAmortization	8798000	USD
	us-gaap	Depreciation And Amortization DepreciationAndAmortization	6815000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	13723000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	13783000	USD
	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	3117000	USD
	us-gaap	Deferred Income Taxes And Tax Credits DeferredIncomeTaxesAndTaxCredits	-17943000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-6428000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	-8073000	USD
	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	20573000	USD
	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	17549000	USD
	us-gaap	Operating Lease Expense OperatingLeaseExpense	2585000	USD
	us-gaap	Operating Lease Expense OperatingLeaseExpense	0	USD
	wal	Accretion And Amortization Fair Market Value Adjustments Relating To Acquisitionsof Loans AccretionAndAmortizationFairMarketValueAdjustmentsRelatingToAcquisitionsofLoans	7413000	USD
	wal	Accretion And Amortization Fair Market Value Adjustments Relating To Acquisitionsof Loans AccretionAndAmortizationFairMarketValueAdjustmentsRelatingToAcquisitionsofLoans	10806000	USD
	wal	Accretionand Amortization Fair Market Value Adjustments Relatingto Acquisitionsof Other Assetsand Liabilities AccretionandAmortizationFairMarketValueAdjustmentsRelatingtoAcquisitionsofOtherAssetsandLiabilities	-927000	USD
	wal	Accretionand Amortization Fair Market Value Adjustments Relatingto Acquisitionsof Other Assetsand Liabilities AccretionandAmortizationFairMarketValueAdjustmentsRelatingtoAcquisitionsofOtherAssetsandLiabilities	-950000	USD
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	1959000	USD
	us-gaap	Bank Owned Life Insurance Income BankOwnedLifeInsuranceIncome	2095000	USD
	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	4406000	USD
	us-gaap	Equity Securities Fv Ni Unrealized Gain Loss EquitySecuritiesFvNiUnrealizedGainLoss	-1759000	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	-513000	USD
	us-gaap	Gain Loss On Sales Of Loans Net GainLossOnSalesOfLoansNet	1443000	USD
	wal	Gain Loss On Foreclosed Assets GainLossOnForeclosedAssets	627000	USD
	wal	Gain Loss On Foreclosed Assets GainLossOnForeclosedAssets	1390000	USD
	wal	Valuation Adjustments Of Other Repossessed Assets Net ValuationAdjustmentsOfOtherRepossessedAssetsNet	-99000	USD
	wal	Valuation Adjustments Of Other Repossessed Assets Net ValuationAdjustmentsOfOtherRepossessedAssetsNet	-33000	USD
	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	-5000	USD
	us-gaap	Gain Loss On Disposition Of Assets GainLossOnDispositionOfAssets	50000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	27439000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	-26419000	USD
	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	61124000	USD
	us-gaap	Increase Decrease In Other Operating Liabilities IncreaseDecreaseInOtherOperatingLiabilities	-10880000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	330280000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	247353000	USD
	us-gaap	Payments To Acquire Available For Sale Securities PaymentsToAcquireAvailableForSaleSecurities	123848000	USD
	us-gaap	Payments To Acquire Available For Sale Securities PaymentsToAcquireAvailableForSaleSecurities	86316000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	230729000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	210003000	USD
	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	56060000	USD
	us-gaap	Payments To Acquire Held To Maturity Securities PaymentsToAcquireHeldToMaturitySecurities	26025000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	4660000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Held To Maturity Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities	489000	USD
	us-gaap	Proceeds From Sale Of Held To Maturity Securities ProceedsFromSaleOfHeldToMaturitySecurities	10000000	USD
	us-gaap	Proceeds From Sale Of Held To Maturity Securities ProceedsFromSaleOfHeldToMaturitySecurities	0	USD
	wal	Paymentsto Acquire Securities Equity PaymentstoAcquireSecuritiesEquity	283000	USD
	wal	Paymentsto Acquire Securities Equity PaymentstoAcquireSecuritiesEquity	41660000	USD
	us-gaap	Proceeds From Dividends Received ProceedsFromDividendsReceived	4695000	USD
	us-gaap	Proceeds From Dividends Received ProceedsFromDividendsReceived	0	USD
	wal	Purchase Of Investment Tax Credits PurchaseOfInvestmentTaxCredits	38607000	USD
	wal	Purchase Of Investment Tax Credits PurchaseOfInvestmentTaxCredits	32631000	USD
	wal	Purchaseof Sbic Investments PurchaseofSBICInvestments	3137000	USD
	wal	Purchaseof Sbic Investments PurchaseofSBICInvestments	1351000	USD
	wal	Proceedsfrom Sale Paymentsto Purchase Investment In Money Market ProceedsfromSalePaymentstoPurchaseInvestmentInMoneyMarket	-137000	USD
	wal	Proceedsfrom Sale Paymentsto Purchase Investment In Money Market ProceedsfromSalePaymentstoPurchaseInvestmentInMoneyMarket	-5000	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	0	USD
	us-gaap	Proceeds From Life Insurance Policies ProceedsFromLifeInsurancePolicies	1112000	USD
	us-gaap	Payments To Acquire Restricted Investments PaymentsToAcquireRestrictedInvestments	85000	USD
	us-gaap	Payments To Acquire Restricted Investments PaymentsToAcquireRestrictedInvestments	171000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	1463570000	USD
	us-gaap	Payments For Proceeds From Loans And Leases PaymentsForProceedsFromLoansAndLeases	968748000	USD
	us-gaap	Payments For Proceeds From Productive Assets PaymentsForProceedsFromProductiveAssets	9164000	USD
	us-gaap	Payments For Proceeds From Productive Assets PaymentsForProceedsFromProductiveAssets	1836000	USD
	us-gaap	Proceeds From Sale Of Wholly Owned Real Estate And Real Estate Acquired In Settlement Of Loans ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans	628000	USD
	us-gaap	Proceeds From Sale Of Wholly Owned Real Estate And Real Estate Acquired In Settlement Of Loans ProceedsFromSaleOfWhollyOwnedRealEstateAndRealEstateAcquiredInSettlementOfLoans	8100000	USD
	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	5744000	USD
	wal	Unfunded Commitments To Purchase Investment Tax Credits UnfundedCommitmentsToPurchaseInvestmentTaxCredits	97552000	USD
	us-gaap	Transfer To Other Real Estate TransferToOtherRealEstate	0	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-1444179000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-939039000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	2262452000	USD
	us-gaap	Increase Decrease In Deposits IncreaseDecreaseInDeposits	1114996000	USD
	us-gaap	Proceeds From Repayments Of Debt ProceedsFromRepaymentsOfDebt	-499490000	USD
	us-gaap	Proceeds From Repayments Of Debt ProceedsFromRepaymentsOfDebt	-322995000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	36000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	534000	USD
	wal	Restrictedstocksurrendered Restrictedstocksurrendered	8051000	USD
	wal	Restrictedstocksurrendered Restrictedstocksurrendered	10799000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	71913000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	0	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	1683034000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	781736000	USD
	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	569135000	USD
	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	90050000	USD
CY2018Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	498572000	USD
CY2017Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	416768000	USD
CY2019Q2	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	1067707000	USD
CY2018Q2	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	506818000	USD
	us-gaap	Interest Paid InterestPaid	90507000	USD
	us-gaap	Interest Paid InterestPaid	46358000	USD
	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	-26994000	USD
	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	14792000	USD
	wal	Unfunded Commitments To Purchase Investment Tax Credits UnfundedCommitmentsToPurchaseInvestmentTaxCredits	58639000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	67300000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-49303000	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	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	2214000	USD
	wal	Changein Unfunded Obligations Non Cash ChangeinUnfundedObligationsNonCash	43500000	USD
	wal	Changein Unfunded Obligations Non Cash ChangeinUnfundedObligationsNonCash	99980000	USD
	wal	Number Of Wholly Owned Subsidiaries Non Bank Subsidiaries NumberOfWhollyOwnedSubsidiariesNonBankSubsidiaries	2	Subsidiary
	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 particularly susceptible to significant changes in the near term 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>
CY2019Q2	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	114689000	USD
CY2018Q4	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	302905000	USD
CY2019Q2	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	435997000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	30861000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	0	USD
CY2019Q2	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	466858000	USD
CY2019Q2	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	3226756000	USD
CY2019Q2	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	52133000	USD
CY2019Q2	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	25795000	USD
CY2019Q2	us-gaap	Available For Sale Securities AvailableForSaleSecurities	3253094000	USD
CY2019Q2	us-gaap	Equity Securities Fv Ni Cost EquitySecuritiesFvNiCost	113387000	USD
CY2019Q2	wal	Equitysecurities Fvni Accumulated Gross Unrealized Gain Before Tax EquitysecuritiesFVNIAccumulatedGrossUnrealizedGainBeforeTax	1964000	USD
CY2019Q2	wal	Equitysecurities Fvni Accumulated Gross Unrealized Loss Before Tax EquitysecuritiesFVNIAccumulatedGrossUnrealizedLossBeforeTax	662000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Gain HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain	3163000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Accumulated Unrecognized Holding Loss HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss	7420000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	298648000	USD
CY2018Q4	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	3339888000	USD
CY2018Q4	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	22054000	USD
CY2018Q4	us-gaap	Available For Sale Securities Accumulated Gross Unrealized Loss Before Tax AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax	84954000	USD
CY2018Q4	us-gaap	Available For Sale Securities AvailableForSaleSecurities	3276988000	USD
CY2018Q4	us-gaap	Equity Securities Fv Ni Cost EquitySecuritiesFvNiCost	118164000	USD
CY2018Q4	wal	Equitysecurities Fvni Accumulated Gross Unrealized Gain Before Tax EquitysecuritiesFVNIAccumulatedGrossUnrealizedGainBeforeTax	148000	USD
CY2018Q4	wal	Equitysecurities Fvni Accumulated Gross Unrealized Loss Before Tax EquitysecuritiesFVNIAccumulatedGrossUnrealizedLossBeforeTax	3251000	USD
CY2018Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	115061000	USD
CY2019Q2	wal	Number Of Securities In Unrealized Position NumberOfSecuritiesInUnrealizedPosition	154	positions
CY2018Q4	wal	Number Of Securities In Unrealized Position NumberOfSecuritiesInUnrealizedPosition	373	positions
	us-gaap	Other Than Temporary Impairment Losses Investments Portion In Other Comprehensive Income Loss Before Tax Including Portion Attributable To Noncontrolling Interest OtherThanTemporaryImpairmentLossesInvestmentsPortionInOtherComprehensiveIncomeLossBeforeTaxIncludingPortionAttributableToNoncontrollingInterest	0	USD
CY2019Q2	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	229000	USD
CY2019Q2	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	67045000	USD
CY2019Q2	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	25566000	USD
CY2019Q2	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	1149873000	USD
CY2019Q2	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	25795000	USD
CY2019Q2	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue	1216918000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	3868000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	91095000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	3552000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	69991000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Accumulated Loss HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	7420000	USD
CY2018Q4	us-gaap	Held To Maturity Securities Continuous Unrealized Loss Position Fair Value HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue	161086000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	10114000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue	574255000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position12 Months Or Longer Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss	74840000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue	2086619000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Accumulated Loss AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss	84954000	USD
CY2018Q4	us-gaap	Available For Sale Securities Continuous Unrealized Loss Position Fair Value AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue	2660874000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount	10100000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Debt Maturities Within One Year Fair Value HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue	10139000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount	24940000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Debt Maturities After One Through Five Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	25714000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Net Carrying Amount HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount	400957000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Debt Maturities After Ten Years Fair Value HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue	431005000	USD
CY2019Q2	us-gaap	Held To Maturity Securities HeldToMaturitySecurities	435997000	USD
CY2019Q2	us-gaap	Held To Maturity Securities Fair Value HeldToMaturitySecuritiesFairValue	466858000	USD
CY2019Q2	us-gaap	Available For Sale Securities Debt Maturities Within One Year Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost	3781000	USD
CY2019Q2	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	3789000	USD
CY2019Q2	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	16012000	USD
CY2019Q2	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	16173000	USD
CY2019Q2	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	209275000	USD
CY2019Q2	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	203657000	USD
CY2019Q2	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	498866000	USD
CY2019Q2	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	525556000	USD
CY2019Q2	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost	2498822000	USD
CY2019Q2	us-gaap	Available For Sale Securities Debt Maturities Without Single Maturity Date Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue	2503919000	USD
CY2019Q2	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	3226756000	USD
CY2019Q2	us-gaap	Available For Sale Securities AvailableForSaleSecurities	3253094000	USD
CY2019Q2	us-gaap	Available For Sale Securities AvailableForSaleSecurities	3253094000	USD
CY2019Q2	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	114689000	USD
CY2018Q4	us-gaap	Available For Sale Securities AvailableForSaleSecurities	3276988000	USD
CY2018Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	115061000	USD
CY2019Q2	us-gaap	Pledged Financial Instruments Not Separately Reported Other Debt Securities Available For Sale Or Held For Investment PledgedFinancialInstrumentsNotSeparatelyReportedOtherDebtSecuritiesAvailableForSaleOrHeldForInvestment	886300000	USD
CY2018Q4	us-gaap	Pledged Financial Instruments Not Separately Reported Other Debt Securities Available For Sale Or Held For Investment PledgedFinancialInstrumentsNotSeparatelyReportedOtherDebtSecuritiesAvailableForSaleOrHeldForInvestment	788400000	USD
CY2019Q2	us-gaap	Debt Securities Held To Maturity Sold Amount DebtSecuritiesHeldToMaturitySoldAmount	10000000.0	USD
CY2019Q2	us-gaap	Held To Maturity Securities Sold Security Realized Gain Loss HeldToMaturitySecuritiesSoldSecurityRealizedGainLoss	0	USD
CY2019Q2	us-gaap	Held To Maturity Securities Sold Security Circumstances Leading To Sale HeldToMaturitySecuritiesSoldSecurityCircumstancesLeadingToSale	The sale of this HTM security was made as a result of a significant change in the issuer’s creditworthiness, representative of a change in circumstance contemplated in ASC 320-10-25 that would not call into question the Company’s intent to hold other debt securities to maturity in the future. Accordingly, management concluded that the Company’s remaining HTM securities are appropriately classified as such as of June 30, 2019.
	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	0	USD
CY2019Q2	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	19250250000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	17710629000	USD
CY2019Q2	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	160409000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	152717000	USD
CY2019Q2	us-gaap	Loans And Leases Receivable Net Reported Amount LoansAndLeasesReceivableNetReportedAmount	19089841000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Reported Amount LoansAndLeasesReceivableNetReportedAmount	17557912000	USD
CY2019Q2	us-gaap	Loans And Leases Receivable Deferred Income LoansAndLeasesReceivableDeferredIncome	40200000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Deferred Income LoansAndLeasesReceivableDeferredIncome	36300000	USD
CY2019Q2	us-gaap	Receivable With Imputed Interest Discount ReceivableWithImputedInterestDiscount	11300000	USD
CY2018Q4	us-gaap	Receivable With Imputed Interest Discount ReceivableWithImputedInterestDiscount	2000000.0	USD
CY2019Q2	wal	Interest Rate Markson Acquired Loans InterestRateMarksonAcquiredLoans	5100000	USD
CY2018Q4	wal	Interest Rate Markson Acquired Loans InterestRateMarksonAcquiredLoans	7100000	USD
CY2019Q2	wal	Credit Markon Acquired Loans CreditMarkonAcquiredLoans	10600000	USD
CY2018Q4	wal	Credit Markon Acquired Loans CreditMarkonAcquiredLoans	14600000	USD
CY2019Q2	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	19214345000	USD
CY2019Q2	us-gaap	Financing Receivable Recorded Investment Past Due FinancingReceivableRecordedInvestmentPastDue	35905000	USD
CY2019Q2	us-gaap	Notes Receivable Net NotesReceivableNet	19250250000	USD
CY2018Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	17673900000	USD
CY2018Q4	us-gaap	Financing Receivable Recorded Investment Past Due FinancingReceivableRecordedInvestmentPastDue	36729000	USD
CY2018Q4	us-gaap	Notes Receivable Net NotesReceivableNet	17710629000	USD
CY2019Q2	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	0	USD
CY2018Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	594000	USD
CY2019Q2	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	500000	USD
CY2018Q2	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	600000	USD
CY2019Q1	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	800000	USD
CY2018Q1	us-gaap	Loans And Leases Receivable Impaired Interest Lost On Nonaccrual Loans LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans	1200000	USD
CY2019Q2	us-gaap	Notes Receivable Net NotesReceivableNet	19250250000	USD
CY2019Q2	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	19214345000	USD
CY2019Q2	us-gaap	Notes Receivable Net NotesReceivableNet	19250250000	USD
CY2018Q4	us-gaap	Notes Receivable Net NotesReceivableNet	17710629000	USD
CY2018Q4	us-gaap	Financing Receivable Recorded Investment Current FinancingReceivableRecordedInvestmentCurrent	17673900000	USD
CY2018Q4	us-gaap	Notes Receivable Net NotesReceivableNet	17710629000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	6090000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	986000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	120341000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	111266000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	126431000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Recorded Investment ImpairedFinancingReceivableRecordedInvestment	112252000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	1854000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	681000	USD
	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	1995000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	113346000	USD
CY2018Q2	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	104403000	USD
	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	119979000	USD
	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	98743000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	1201000	USD
CY2018Q2	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	1122000	USD
	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	2694000	USD
CY2019Q2	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	126431000	USD
CY2018Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	112252000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	113346000	USD
CY2018Q2	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	104403000	USD
	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	119979000	USD
	us-gaap	Impaired Financing Receivable Average Recorded Investment ImpairedFinancingReceivableAverageRecordedInvestment	98743000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	1201000	USD
CY2018Q2	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	1122000	USD
	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	2694000	USD
	us-gaap	Impaired Financing Receivable Interest Income Accrual Method ImpairedFinancingReceivableInterestIncomeAccrualMethod	1995000	USD
CY2019Q2	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	51825000	USD
CY2018Q4	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	27746000	USD
CY2019Q2	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	0	USD
CY2018Q4	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	594000	USD
CY2019Q2	wal	Troubled Debt Restructured Loans TroubledDebtRestructuredLoans	52200000	USD
CY2018Q4	wal	Troubled Debt Restructured Loans TroubledDebtRestructuredLoans	36458000	USD
CY2019Q2	wal	Non Performing Loans NonPerformingLoans	104025000	USD
CY2018Q4	wal	Non Performing Loans NonPerformingLoans	64798000	USD
CY2019Q2	us-gaap	Foreclosed Assets ForeclosedAssets	17707000	USD
CY2018Q4	us-gaap	Foreclosed Assets ForeclosedAssets	17924000	USD
CY2019Q2	wal	Non Performing Assets NonPerformingAssets	121732000	USD
CY2018Q4	wal	Non Performing Assets NonPerformingAssets	82722000	USD
CY2018Q4	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield	3768000	USD
CY2017Q4	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield	9324000	USD
CY2019Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Reclassifications From Nonaccretable Difference CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldReclassificationsFromNonaccretableDifference	0	USD
CY2019Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	142000	USD
CY2018Q2	us-gaap	Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Accretable Yield Accretion CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAccretion	264000	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 Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	7000000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	160409000	USD
CY2018Q1	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	144659000	USD
CY2018Q2	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	3901000	USD
CY2018Q2	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	1325000	USD
CY2018Q2	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	5000000	USD
CY2018Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	147083000	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
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	10500000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	160409000	USD
CY2017Q4	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	140050000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Write Offs FinancingReceivableAllowanceForCreditLossesWriteOffs	7526000	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	1854000	USD
	us-gaap	Financing Receivable Allowance For Credit Losses Recovery FinancingReceivableAllowanceForCreditLossesRecovery	3559000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	11000000	USD
CY2018Q2	us-gaap	Financing Receivable Allowance For Credit Losses FinancingReceivableAllowanceForCreditLosses	147083000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	6090000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	120341000	USD
CY2019Q2	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	126431000	USD
CY2019Q2	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	19061461000	USD
CY2019Q2	us-gaap	Loans And Leases Receivable Gross Carrying Amount LoansAndLeasesReceivableGrossCarryingAmount	19250250000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable With Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance	6164000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance	131033000	USD
CY2019Q2	wal	Impaired Financing Receivable Unpaid Principal Balance Individually Evaluated For Impairment ImpairedFinancingReceivableUnpaidPrincipalBalanceIndividuallyEvaluatedForImpairment	137197000	USD
CY2019Q2	wal	Financing Receivable Unpaid Principal Balance Collectively Evaluated For Impairment FinancingReceivableUnpaidPrincipalBalanceCollectivelyEvaluatedForImpairment	19058999000	USD
CY2019Q2	wal	Financing Receivable Unpaid Principal Balance FinancingReceivableUnpaidPrincipalBalance	19271829000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	1854000	USD
CY2019Q2	wal	Impaired Financing Receivable With No Related Allowance ImpairedFinancingReceivableWithNoRelatedAllowance	0	USD
CY2019Q2	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	158456000	USD
CY2019Q2	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	160409000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	986000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Recorded Investment ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment	111266000	USD
CY2018Q4	us-gaap	Financing Receivable Individually Evaluated For Impairment FinancingReceivableIndividuallyEvaluatedForImpairment	112252000	USD
CY2018Q4	us-gaap	Financing Receivable Collectively Evaluated For Impairment FinancingReceivableCollectivelyEvaluatedForImpairment	17514822000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Gross Carrying Amount LoansAndLeasesReceivableGrossCarryingAmount	17710629000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance	1845000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With No Related Allowance Unpaid Principal Balance ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance	198234000	USD
CY2018Q4	wal	Impaired Financing Receivable Unpaid Principal Balance Individually Evaluated For Impairment ImpairedFinancingReceivableUnpaidPrincipalBalanceIndividuallyEvaluatedForImpairment	200079000	USD
CY2018Q4	wal	Financing Receivable Unpaid Principal Balance Collectively Evaluated For Impairment FinancingReceivableUnpaidPrincipalBalanceCollectivelyEvaluatedForImpairment	17514822000	USD
CY2018Q4	wal	Financing Receivable Unpaid Principal Balance FinancingReceivableUnpaidPrincipalBalance	17820320000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable Related Allowance ImpairedFinancingReceivableRelatedAllowance	681000	USD
CY2018Q4	wal	Impaired Financing Receivable With No Related Allowance ImpairedFinancingReceivableWithNoRelatedAllowance	0	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Losses Individually Evaluated For Impairment1 FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1	681000	USD
CY2018Q4	us-gaap	Financing Receivable Allowance For Credit Losses Collectively Evaluated For Impairment FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment	151940000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Allowance LoansAndLeasesReceivableAllowance	152717000	USD
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CY2019Q1	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	1800000	USD
CY2018Q1	us-gaap	Financing Receivable Modifications Number Of Contracts2 FinancingReceivableModificationsNumberOfContracts2	2
CY2018Q1	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	16600000	USD
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	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	28900000	USD
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	us-gaap	Financing Receivable Modifications Post Modification Recorded Investment2 FinancingReceivableModificationsPostModificationRecordedInvestment2	31600000	USD
	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	400000	USD
	us-gaap	Financing Receivable Modifications Subsequent Default Recorded Investment1 FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1	0	USD
CY2019Q2	wal	Loans And Loans Receivable Purchases LoansAndLoansReceivablePurchases	590600000	USD
CY2018Q2	wal	Loans And Loans Receivable Purchases LoansAndLoansReceivablePurchases	316800000	USD
CY2019Q1	wal	Loans And Loans Receivable Purchases LoansAndLoansReceivablePurchases	1120000000	USD
CY2018Q1	wal	Loans And Loans Receivable Purchases LoansAndLoansReceivablePurchases	458300000	USD
CY2019Q2	us-gaap	Financing Receivable Significant Sales FinancingReceivableSignificantSales	19300000	USD
CY2019Q2	us-gaap	Loans And Leases Receivable Gain Loss On Sales Net LoansAndLeasesReceivableGainLossOnSalesNet	-100000	USD
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CY2019Q2	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P8Y10M24D
CY2018Q2	us-gaap	Financing Receivable Significant Sales FinancingReceivableSignificantSales	3100000	USD
CY2018Q2	us-gaap	Loans And Leases Receivable Gain Loss On Sales Net LoansAndLeasesReceivableGainLossOnSalesNet	800000	USD
	us-gaap	Financing Receivable Significant Sales FinancingReceivableSignificantSales	34800000	USD
	us-gaap	Loans And Leases Receivable Gain Loss On Sales Net LoansAndLeasesReceivableGainLossOnSalesNet	-500000	USD
	us-gaap	Financing Receivable Significant Sales FinancingReceivableSignificantSales	34100000	USD
	us-gaap	Loans And Leases Receivable Gain Loss On Sales Net LoansAndLeasesReceivableGainLossOnSalesNet	1400000	USD
CY2019Q2	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	71100000	USD
CY2019Q2	us-gaap	Operating Lease Liability OperatingLeaseLiability	76200000	USD
CY2019Q2	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	6018000	USD
CY2019Q2	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	11297000	USD
CY2019Q2	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	9243000	USD
CY2019Q2	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	8049000	USD
CY2019Q2	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	8068000	USD
CY2019Q2	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	46320000	USD
CY2019Q2	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	88995000	USD
CY2019Q2	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	12804000	USD
CY2019Q2	us-gaap	Operating Lease Liability OperatingLeaseLiability	76191000	USD
CY2019Q2	wal	Lesseeoperatingleaseleasesnotyetcommencedaggregatedcommitment Lesseeoperatingleaseleasesnotyetcommencedaggregatedcommitment	3900000	USD
CY2019Q2	us-gaap	Lease Cost LeaseCost	3100000	USD
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CY2019Q2	wal	Lesseeoperatingleaseothercost Lesseeoperatingleaseothercost	900000	USD
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CY2018Q2	us-gaap	Lease Cost LeaseCost	2800000	USD
	us-gaap	Lease Cost LeaseCost	5300000	USD
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CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due In Two Years OperatingLeasesFutureMinimumPaymentsDueInTwoYears	10322000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due In Three Years OperatingLeasesFutureMinimumPaymentsDueInThreeYears	7418000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due In Four Years OperatingLeasesFutureMinimumPaymentsDueInFourYears	6294000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due In Five Years OperatingLeasesFutureMinimumPaymentsDueInFiveYears	6070000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due Thereafter OperatingLeasesFutureMinimumPaymentsDueThereafter	15417000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due OperatingLeasesFutureMinimumPaymentsDue	56891000	USD
CY2019Q2	us-gaap	Federal Funds Purchased FederalFundsPurchased	0	USD
CY2018Q4	us-gaap	Federal Funds Purchased FederalFundsPurchased	256000000	USD
CY2019Q2	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due Within One Year Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate	0	USD
CY2018Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due Within One Year Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate	235000000	USD
CY2019Q2	us-gaap	Short Term Borrowings ShortTermBorrowings	0	USD
CY2018Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	491000000	USD
CY2019Q2	us-gaap	Federal Funds Purchased FederalFundsPurchased	0	USD
CY2018Q4	us-gaap	Federal Funds Purchased FederalFundsPurchased	256000000.0	USD
CY2019Q2	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due Within One Year Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate	0	USD
CY2018Q4	us-gaap	Federal Home Loan Bank Advances Maturities Summary Due Within One Year Of Balance Sheet Date FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate	235000000.0	USD
CY2018	us-gaap	Federal Home Loan Bank Advances Activity For Year Average Interest Rate For Year FederalHomeLoanBankAdvancesActivityForYearAverageInterestRateForYear	0.0256
CY2019Q2	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	13900000	USD
CY2018Q4	us-gaap	Securities Sold Under Agreements To Repurchase SecuritiesSoldUnderAgreementsToRepurchase	22400000	USD
CY2019Q2	us-gaap	Subordinated Debt SubordinatedDebt	316400000	USD
CY2018Q4	us-gaap	Subordinated Debt SubordinatedDebt	299400000	USD
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CY2019Q2	us-gaap	Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust	70800000	USD
CY2018Q4	us-gaap	Junior Subordinated Debenture Owed To Unconsolidated Subsidiary Trust JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust	61100000	USD
CY2019Q2	us-gaap	Stock Repurchase Program Authorized Amount1 StockRepurchaseProgramAuthorizedAmount1	250000000.0	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
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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
CY2019Q2	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	3145	shares
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CY2019Q2	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	47.16
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CY2018Q2	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	2085	shares
	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	182952	shares
CY2018Q2	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	59.46
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CY2019Q1	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-8191000	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
CY2019Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	34572000	USD
CY2019Q2	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	26381000	USD
CY2018Q1	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-41662000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	-9653000	USD
CY2018Q2	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	0	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-9653000	USD
CY2018Q2	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-51315000	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
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CY2019Q2	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	26381000	USD
CY2017Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-3145000	USD
CY2018Q1	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-4203000	USD
	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	-47112000	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	-47112000	USD
CY2018Q2	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-51315000	USD
CY2019Q2	us-gaap	Other Derivatives Not Designated As Hedging Instruments At Fair Value Net OtherDerivativesNotDesignatedAsHedgingInstrumentsAtFairValueNet	100000	USD
CY2018Q4	us-gaap	Other Derivatives Not Designated As Hedging Instruments At Fair Value Net OtherDerivativesNotDesignatedAsHedgingInstrumentsAtFairValueNet	300000	USD
CY2018Q2	us-gaap	Other Derivatives Not Designated As Hedging Instruments At Fair Value Net OtherDerivativesNotDesignatedAsHedgingInstrumentsAtFairValueNet	200000	USD
CY2019Q2	us-gaap	Gain Loss On Foreign Currency Derivative Instruments Not Designated As Hedging Instruments GainLossOnForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstruments	1000000.0	USD
CY2018Q2	us-gaap	Gain Loss On Foreign Currency Derivative Instruments Not Designated As Hedging Instruments GainLossOnForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstruments	1200000	USD
CY2019Q1	us-gaap	Gain Loss On Foreign Currency Derivative Instruments Not Designated As Hedging Instruments GainLossOnForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstruments	2300000	USD
CY2018Q1	us-gaap	Gain Loss On Foreign Currency Derivative Instruments Not Designated As Hedging Instruments GainLossOnForeignCurrencyDerivativeInstrumentsNotDesignatedAsHedgingInstruments	2400000	USD
CY2019Q2	wal	Derivative Amountof Hedged Item Loans DerivativeAmountofHedgedItemLoans	678369000	USD
CY2019Q2	us-gaap	Hedged Asset Fair Value Hedge Cumulative Increase Decrease HedgedAssetFairValueHedgeCumulativeIncreaseDecrease	58355000	USD
CY2018Q4	wal	Derivative Amountof Hedged Item Loans DerivativeAmountofHedgedItemLoans	650428000	USD
CY2018Q4	us-gaap	Hedged Asset Fair Value Hedge Cumulative Increase Decrease HedgedAssetFairValueHedgeCumulativeIncreaseDecrease	23039000	USD
CY2019Q2	us-gaap	Derivative Amount Of Hedged Item DerivativeAmountOfHedgedItem	-316392000	USD
CY2019Q2	us-gaap	Hedged Liability Fair Value Hedge Cumulative Increase Decrease HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease	2963000	USD
CY2018Q4	us-gaap	Derivative Amount Of Hedged Item DerivativeAmountOfHedgedItem	-299401000	USD
CY2018Q4	us-gaap	Hedged Liability Fair Value Hedge Cumulative Increase Decrease HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease	19691000	USD
CY2019Q2	wal	Collateral Netted Against Derivative Liabilities CollateralNettedAgainstDerivativeLiabilities	62800000	USD
CY2018Q4	wal	Collateral Netted Against Derivative Liabilities CollateralNettedAgainstDerivativeLiabilities	44900000	USD
CY2018Q2	wal	Collateral Netted Against Derivative Liabilities CollateralNettedAgainstDerivativeLiabilities	39800000	USD
CY2019Q2	wal	Over Collateralization On Derivatives To Banks After Application Of Master Netting Agreements And Collateral OverCollateralizationOnDerivativesToBanksAfterApplicationOfMasterNettingAgreementsAndCollateral	20300000	USD
CY2019Q2	wal	Additional Collateral Amount AdditionalCollateralAmount	83100000	USD
CY2018Q4	wal	Over Collateralization On Derivatives To Banks After Application Of Master Netting Agreements And Collateral OverCollateralizationOnDerivativesToBanksAfterApplicationOfMasterNettingAgreementsAndCollateral	7600000	USD
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CY2019Q2	wal	Dilutive Effect Of Stock Options Restricted Stock And Equity Settled Awards DilutiveEffectOfStockOptionsRestrictedStockAndEquitySettledAwards	482000	shares
CY2018Q2	wal	Dilutive Effect Of Stock Options Restricted Stock And Equity Settled Awards DilutiveEffectOfStockOptionsRestrictedStockAndEquitySettledAwards	729000	shares
	wal	Dilutive Effect Of Stock Options Restricted Stock And Equity Settled Awards DilutiveEffectOfStockOptionsRestrictedStockAndEquitySettledAwards	462000	shares
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CY2019Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	103501000	shares
CY2018Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	105420000	shares
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CY2019Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	122936000	USD
CY2018Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	104679000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	243732000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	205579000	USD
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.19
CY2018Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.00
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CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.19
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CY2019Q1	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	0	shares
CY2019Q2	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.1676
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CY2019Q2	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	9300000	USD
	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	-22700000	USD
CY2019Q2	us-gaap	Deferred Tax Assets Liabilities Net DeferredTaxAssetsLiabilitiesNet	9300000	USD
CY2019Q2	us-gaap	Operating Loss Carryforwards Valuation Allowance OperatingLossCarryforwardsValuationAllowance	2400000	USD
CY2019Q2	us-gaap	Amortization Method Qualified Affordable Housing Project Investments AmortizationMethodQualifiedAffordableHousingProjectInvestments	321500000	USD
CY2018Q4	us-gaap	Amortization Method Qualified Affordable Housing Project Investments AmortizationMethodQualifiedAffordableHousingProjectInvestments	342400000	USD
CY2019Q2	us-gaap	Affordable Housing Program Obligation AffordableHousingProgramObligation	133100000	USD
CY2018Q4	us-gaap	Affordable Housing Program Obligation AffordableHousingProgramObligation	171700000	USD
CY2019Q2	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	10500000	USD
CY2018Q2	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	9400000	USD
	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	20600000	USD
	us-gaap	Amortization Method Qualified Affordable Housing Project Investments Amortization AmortizationMethodQualifiedAffordableHousingProjectInvestmentsAmortization	17500000	USD
	us-gaap	Line Of Credit Facility Expiration Period LineOfCreditFacilityExpirationPeriod	P1Y
CY2019Q2	us-gaap	Fair Value Disclosure Offbalance Sheet Risks Face Amount Liability FairValueDisclosureOffbalanceSheetRisksFaceAmountLiability	9081838000	USD
CY2018Q4	us-gaap	Fair Value Disclosure Offbalance Sheet Risks Face Amount Liability FairValueDisclosureOffbalanceSheetRisksFaceAmountLiability	8184214000	USD
	wal	Maximum Loan To Value Ratio MaximumLoanToValueRatio	0.75
CY2019Q2	wal	Percentage Of Commercial Real Estate Loans Occupied By Owners PercentageOfCommercialRealEstateLoansOccupiedByOwners	0.32
CY2018Q4	wal	Percentage Of Commercial Real Estate Loans Occupied By Owners PercentageOfCommercialRealEstateLoansOccupiedByOwners	0.36
CY2019Q2	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	-1334000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	748000	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	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	2214000	USD
CY2019Q2	us-gaap	Fair Value Liabilities Measured On Recurring Basis Subordinated Debt Obligations FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations	58315000	USD
CY2019Q2	us-gaap	Hedged Asset Fair Value Hedge Cumulative Increase Decrease HedgedAssetFairValueHedgeCumulativeIncreaseDecrease	58355000	USD
CY2019Q2	us-gaap	Hedged Liability Fair Value Hedge Cumulative Increase Decrease HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease	2963000	USD
CY2018Q4	us-gaap	Fair Value Liabilities Measured On Recurring Basis Subordinated Debt Obligations FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations	48684000	USD
CY2018Q4	us-gaap	Hedged Asset Fair Value Hedge Cumulative Increase Decrease HedgedAssetFairValueHedgeCumulativeIncreaseDecrease	23039000	USD
CY2018Q4	us-gaap	Hedged Liability Fair Value Hedge Cumulative Increase Decrease HedgedLiabilityFairValueHedgeCumulativeIncreaseDecrease	19691000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	-1300000	USD
CY2018Q2	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	700000	USD
	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	-7300000	USD
	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	2200000	USD
CY2019Q2	wal	Impaired Financing Receivables With Norelated Allowance Balanceswith Chargeoffs ImpairedFinancingReceivablesWithNorelatedAllowanceBalanceswithChargeoffs	12300000	USD
CY2018Q4	wal	Impaired Financing Receivables With Norelated Allowance Balanceswith Chargeoffs ImpairedFinancingReceivablesWithNorelatedAllowanceBalanceswithChargeoffs	19400000	USD
CY2019Q2	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	6100000	USD
CY2018Q4	us-gaap	Impaired Financing Receivable With Related Allowance Recorded Investment ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment	1000000.0	USD
CY2019Q2	wal	Cash Cash Equivalentsand Investment Securities CashCashEquivalentsandInvestmentSecurities	4937800000	USD
CY2019Q2	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	19250300000	USD
CY2019Q2	wal	Loansand Leases Receivable Including Heldfor Sale Net LoansandLeasesReceivableIncludingHeldforSaleNet	19089900000	USD
CY2019Q2	us-gaap	Other Foreclosed Assets OtherForeclosedAssets	17700000	USD
CY2019Q2	us-gaap	Intangible Assets Net Including Goodwill IntangibleAssetsNetIncludingGoodwill	298400000	USD
CY2019Q2	wal	Other Assets Segment OtherAssetsSegment	971000000.0	USD
CY2019Q2	us-gaap	Deposits Deposits	21439900000	USD
CY2019Q2	wal	Borrowingsand Qualifying Debt BorrowingsandQualifyingDebt	387200000	USD
CY2019Q2	wal	Other Liabilities Segment OtherLiabilitiesSegment	636400000	USD
CY2019Q2	us-gaap	Stockholders Equity StockholdersEquity	2851300000	USD
CY2019Q2	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	25314800000	USD
CY2019Q2	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	7000000	USD
CY2019Q2	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	247681000	USD
CY2019Q2	us-gaap	Noninterest Income NoninterestIncome	14218000	USD
CY2019Q2	us-gaap	Noninterest Expense NoninterestExpense	114213000	USD
CY2019Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	147686000	USD
CY2019Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	24750000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	122936000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	502017000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	10500000	USD
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	491517000	USD
	us-gaap	Noninterest Income NoninterestIncome	29628000	USD
	us-gaap	Noninterest Expense NoninterestExpense	227127000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	294018000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	50286000	USD
	us-gaap	Net Income Loss NetIncomeLoss	243732000	USD
CY2018Q4	wal	Cash Cash Equivalentsand Investment Securities CashCashEquivalentsandInvestmentSecurities	4259700000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Of Deferred Income LoansAndLeasesReceivableNetOfDeferredIncome	17710600000	USD
CY2018Q4	us-gaap	Loans And Leases Receivable Net Reported Amount LoansAndLeasesReceivableNetReportedAmount	17557900000	USD
CY2018Q4	us-gaap	Other Foreclosed Assets OtherForeclosedAssets	17900000	USD
CY2018Q4	us-gaap	Intangible Assets Net Including Goodwill IntangibleAssetsNetIncludingGoodwill	299200000	USD
CY2018Q4	wal	Other Assets Segment OtherAssetsSegment	974800000	USD
CY2018Q4	us-gaap	Assets Assets	23109500000	USD
CY2018Q4	us-gaap	Deposits Deposits	19177400000	USD
CY2018Q4	wal	Borrowingsand Qualifying Debt BorrowingsandQualifyingDebt	851500000	USD
CY2018Q4	wal	Other Liabilities Segment OtherLiabilitiesSegment	466900000	USD
CY2018Q4	us-gaap	Liabilities Liabilities	20495800000	USD
CY2018Q4	us-gaap	Stockholders Equity StockholdersEquity	2613700000	USD
CY2018Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	23109500000	USD
CY2018Q4	wal	Excess Funds Providedby Usedin Segment Basis ExcessFundsProvidedbyUsedinSegmentBasis	0	USD
CY2018Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	224108000	USD
CY2018Q2	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	5000000	USD
CY2018Q2	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	219108000	USD
CY2018Q2	us-gaap	Noninterest Income NoninterestIncome	13444000	USD
CY2018Q2	us-gaap	Noninterest Expense NoninterestExpense	102548000	USD
CY2018Q2	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	130004000	USD
CY2018Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	25325000	USD
CY2018Q2	us-gaap	Net Income Loss NetIncomeLoss	104679000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	438328000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	11000000	USD
	us-gaap	Interest Income Expense After Provision For Loan Loss InterestIncomeExpenseAfterProvisionForLoanLoss	427328000	USD
	us-gaap	Noninterest Income NoninterestIncome	25087000	USD
	us-gaap	Noninterest Expense NoninterestExpense	200697000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	251718000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	46139000	USD
	us-gaap	Net Income Loss NetIncomeLoss	205579000	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
CY2018Q2	us-gaap	Fees And Commissions Mortgage Banking And Servicing FeesAndCommissionsMortgageBankingAndServicing	5672000	USD
CY2018Q2	wal	Debitandcreditcardinterchangefees Debitandcreditcardinterchangefees	1648000	USD
CY2018Q2	wal	Success Fees SuccessFees	914000	USD
CY2018Q2	wal	Othernoninterestincome Othernoninterestincome	175000	USD
CY2018Q2	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	8409000	USD
CY2018Q2	wal	Otherrevenue Otherrevenue	5035000	USD
CY2018Q2	us-gaap	Noninterest Income NoninterestIncome	13444000	USD
	us-gaap	Fees And Commissions Mortgage Banking And Servicing FeesAndCommissionsMortgageBankingAndServicing	11417000	USD
	wal	Debitandcreditcardinterchangefees Debitandcreditcardinterchangefees	3155000	USD
	wal	Success Fees SuccessFees	1695000	USD
	wal	Othernoninterestincome Othernoninterestincome	411000	USD
	us-gaap	Contract With Customer Liability Revenue Recognized ContractWithCustomerLiabilityRevenueRecognized	16678000	USD
	wal	Otherrevenue Otherrevenue	8409000	USD
	us-gaap	Noninterest Income NoninterestIncome	25087000	USD
CY2019Q2	us-gaap	Accounts Receivable Net AccountsReceivableNet	1500000	USD
CY2018Q4	us-gaap	Accounts Receivable Net AccountsReceivableNet	1400000	USD

Files In Submission

Name	View Source	Status
0001212545-19-000108-index-headers.html	Edgar Link	pending
0001212545-19-000108-index.html	Edgar Link	pending
0001212545-19-000108.txt	Edgar Link	pending
0001212545-19-000108-xbrl.zip	Edgar Link	pending
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Financial_Report.xlsx	Edgar Link	pending
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report.css	Edgar Link	pending
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wal-20190630.xsd	Edgar Link	pending
wal-20190630_cal.xml	Edgar Link	unprocessable
wal-20190630_def.xml	Edgar Link	unprocessable
wal-20190630_lab.xml	Edgar Link	unprocessable
wal-20190630_pre.xml	Edgar Link	unprocessable
wal630201910-q.htm	Edgar Link	pending
wal630201910-q_htm.xml	Edgar Link	completed
walex3116302019.htm	Edgar Link	pending
walex3126302019.htm	Edgar Link	pending
walex326302019.htm	Edgar Link	pending

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$WAL
WESTERN ALLIANCE BANCORPORATION Stock $wal

2019 Q2 Form 10-Q Financial Statement

#000121254519000108 Filed on August 01, 2019

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WAL WESTERN ALLIANCE BANCORPORATION Stock $wal

2019 Q2 Form 10-Q Financial Statement

#000121254519000108 Filed on August 01, 2019

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WAL
WESTERN ALLIANCE BANCORPORATION Stock $wal