v3.26.3
Derivative Financial Instruments (Fair Value of Derivatives by Balance Sheet Location) (Details) - USD ($)
$ in Thousands
Sep. 30, 2026
Dec. 31, 2025
Derivatives, Fair Value [Line Items]    
Accrued interest receivable $ 20,400 $ 20,100
Interest rate swaps | Derivatives Designated as Hedging Instruments    
Derivatives, Fair Value [Line Items]    
Accrued interest receivable 31 35
Accrued interest payable 47 23
Interest rate swaps | Derivatives Designated as Hedging Instruments | Cash Flow Hedging Instruments    
Derivatives, Fair Value [Line Items]    
Notional amount 120,000 120,000
Interest rate cash flow hedge asset at fair value [1] 1,562 126
Interest rate cash flow hedge liability at fair value [1] 47 979
Interest rate swaps | Derivatives Designated as Hedging Instruments | Fair Value Hedging Instruments    
Derivatives, Fair Value [Line Items]    
Notional amount 100,000 100,000
Interest rate fair value hedge asset at fair value 2,255 335
Interest rate fair value hedge liability at fair value 0 0
Interest rate collars | Derivatives Designated as Hedging Instruments | Cash Flow Hedging Instruments    
Derivatives, Fair Value [Line Items]    
Notional amount 50,000 100,000
Interest rate cash flow hedge asset at fair value 55 0
Interest rate cash flow hedge liability at fair value 0 17
Interest rate floors | Derivatives Designated as Hedging Instruments | Cash Flow Hedging Instruments    
Derivatives, Fair Value [Line Items]    
Notional amount 200,000 200,000
Interest rate cash flow hedge asset at fair value 12 125
Interest rate cash flow hedge liability at fair value 0 0
Interest rate contracts with customers | Derivatives Not Designated as Hedging Instruments    
Derivatives, Fair Value [Line Items]    
Notional amount 965,418 882,941
Derivative assets not designated as hedging instruments 163 6,326
Derivative liabilities not designated as hedging instruments 50,933 27,959
Mirror interest rate contracts with counterparties | Derivatives Not Designated as Hedging Instruments    
Derivatives, Fair Value [Line Items]    
Notional amount 965,418 882,941
Derivative assets not designated as hedging instruments 50,777 27,857
Derivative liabilities not designated as hedging instruments 163 6,392
Risk participation agreements | Derivatives Not Designated as Hedging Instruments    
Derivatives, Fair Value [Line Items]    
Notional amount 293,229 304,854
Derivative assets not designated as hedging instruments 0 28
Derivative liabilities not designated as hedging instruments 0 1
Interest rate lock commitments | Derivatives Not Designated as Hedging Instruments    
Derivatives, Fair Value [Line Items]    
Notional amount 40,517 30,373
Derivative assets not designated as hedging instruments 267 603
Derivative liabilities not designated as hedging instruments 207 12
Forward sale commitments | Derivatives Not Designated as Hedging Instruments    
Derivatives, Fair Value [Line Items]    
Notional amount 72,877 90,813
Derivative assets not designated as hedging instruments 1,077 13
Derivative liabilities not designated as hedging instruments 186 828
Derivative assets    
Derivatives, Fair Value [Line Items]    
Gross derivative assets 56,168 35,413
Less: derivative asset amounts offset [2] 210 6,643
Derivative asset balances, net of offset 55,958 28,770
Less: collateral pledged, derivative assets [3] 0 0
Net amounts 55,958 28,770
Derivative liabilities    
Derivatives, Fair Value [Line Items]    
Gross derivative liabilities 51,536 36,188
Less: derivative liability amounts offset [2] 210 6,643
Derivative liability balances, net of offset 51,326 29,545
Less: collateral pledged, derivative liabilities [3] 0 0
Net amounts $ 51,326 $ 29,545
[1] The fair value of derivative assets includes accrued interest receivable of $31 thousand and $35 thousand, respectively, at September 30, 2026 and December 31, 2025. The fair value of derivative liabilities includes accrued interest payable of $47 thousand and $23 thousand, respectively, at September 30, 2026 and December 31, 2025.
[2] Interest rate risk management contracts and loan related derivative contracts with counterparties are subject to master netting arrangements.
[3] Collateral contractually required to be pledged to derivative counterparties is in the form of cash. Washington Trust may need to post additional collateral in the future in proportion to potential increases in unrealized loss positions.