Fair Value Measurements (Q3) (Details)	Mar. 18, 2021 USD ($)
Fair Value Disclosures [Abstract]
Derivative liability amount	$ 11,655,000

Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

No definition available.

Name:	wald_DerivativeAssetLiabilitiesAtFairValueNet
Namespace Prefix:	wald_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant