Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2020	Apr. 29, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K/A
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	001-38788
Entity Registrant Name	Watford Holdings Ltd.
Entity Incorporation, State or Country Code	D0
Entity Tax Identification Number	98-1155442
Entity Address, Address Line One	Waterloo House, 1st Floor
Entity Address, Address Line Two	100 Pitts Bay Road,
Entity Address, City or Town	Pembroke
Entity Address, Postal Zip Code	HM 08,
Entity Address, Country	BM
City Area Code	(441)
Local Phone Number	278-3455
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Shell Company	false
ICFR Auditor Attestation Flag	false
Entity Listings [Line Items]
Current Fiscal Year End Date	--12-31
Entity Public Float			$ 282.9
Entity Common Stock, Shares Outstanding		19,924,220
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2020
Current Fiscal Year End Date	--12-31
Entity Central Index Key	0001601669
Amendment Flag	true
Amendment Description	On February 26, 2021, the Company filed its Annual Report on Form 10-K for the fiscal year ended December 31, 2020 (the “Original Form 10-K”) with the U.S. Securities and Exchange Commission (the “SEC”). The Company is filing this Amendment No. 1 on Form 10-K/A (the “Form 10-K/A”) because it does not expect to file a proxy statement for its 2020 Annual General Meeting of Shareholders. This Form 10-K/A amends and restates in its entirety Part III, Items 10 through 14 of the Original Form 10-K, to include information previously omitted from the Original Form 10-K in reliance on General Instruction G(3) to Form 10-K. In this Form 10-K/A, unless the context indicates otherwise, the designations “Watford,” the “Company,” “we,” “us” or “our” refer to Watford Holdings Ltd. and its subsidiaries.
Common shares
Entity Listings [Line Items]
Title of 12(b) Security	Common Shares
Trading Symbol	WTRE
Security Exchange Name	NASDAQ
Contingently redeemable preference share
Entity Listings [Line Items]
Title of 12(b) Security	8½% Cumulative Redeemable Preference Shares
Trading Symbol	WTREP
Security Exchange Name	NASDAQ

Watford Holdings Ltd. 10-K/A