Statutory Balances And Accounting Practices (Schedule Of Statutory Net Income And Capital And Surplus) (Details) (USD $)	12 Months Ended						3 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009		Dec. 31, 2010 Dividend Declared [Member]
Statutory Balances And Accounting Practices [Line Items]
Statutory net income	$ 223,447,000	[1]	$ 142,981,000	[1]	$ 186,995,000	[1]
Statutory capital and surplus	1,497,609,000	[2]	1,322,270,000	[2]	1,517,864,000	[2]
Extraordinary intercompany dividend declared							$ 270,000,000

[1] Statutory net income excludes changes in the fair value of the investment portfolio as a result of the application of fair value option.

[2] The decrease in statutory capital and surplus in 2010 was primarily due to a $270 million extraordinary intercompany dividend declared by MCC in the fourth quarter of 2010. The dividend was paid to Mercury General in 2011.