Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 11, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	001-12257
Entity Registrant Name	MERCURY GENERAL CORPORATION
Entity Incorporation, State or Country Code	CA
Entity Tax Identification Number	95-2211612
Entity Address, Address Line One	4484 Wilshire Boulevard
Entity Address, City or Town	Los Angeles,
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	90010
City Area Code	323
Local Phone Number	937-1060
Title of 12(b) Security	Common Stock
Trading Symbol	MCY
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 1,079,757,233
Entity Common Stock, Shares Outstanding		55,357,691
Documents Incorporated by Reference	Certain information from the registrant’s definitive proxy statement for the 2021 Annual Meeting of Shareholders is incorporated herein by reference into Part III hereof.
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Central Index Key	0000064996
Current Fiscal Year End Date	--12-31