Nature of Operations (Details)	12 Months Ended
	Dec. 31, 2011
Property and casualty insurance operations
Product information
Number of states in which the Property and Casualty Group operates	11
Private passenger automobile
Product information
Percentage of property and casualty direct written premiums	47.00%
Homeowners
Product information
Percentage of property and casualty direct written premiums	22.00%
Commercial multi-peril
Product information
Percentage of property and casualty direct written premiums	12.00%
Commercial automobile
Product information
Percentage of property and casualty direct written premiums	7.00%
Workers compensation
Product information
Percentage of property and casualty direct written premiums	7.00%