SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES- CASH (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Average balances	$ 9.2	$ 11.0

Average balances to be maintained on hand or with correspondent banks.

No definition available.

Name:	wk_AverageBalancesToBeMaintainedOnHandOrWithCorrespondentBanks
Namespace Prefix:	wk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant