Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Unpaid principal balance of loans repurchased	$ 1,000	$ 1,400
Reserve for loans repurchases	$ 265	$ 275

This amount represents a reserve for exposure to losses from the obligation to repurchase previously sold residential mortgage loans.

No definition available.

Name:	wash_ReserveForExposureToLossesFromLoanRepurchases
Namespace Prefix:	wash_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant