Statutory Accounting (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012
Summary of reported total capital and surplus as well as the amount of dividends available for distribution
Available for Distribution	$ 124.9
Bermuda [Member]
Summary of reported total capital and surplus as well as the amount of dividends available for distribution
Reported Capital & Surplus	199.4
Available for Distribution	101.4
ASRe [Member] | Bermuda [Member]
Summary of reported total capital and surplus as well as the amount of dividends available for distribution
Reported Capital & Surplus	197.5
Available for Distribution	99.7
ASA [Member] | Bermuda [Member]
Summary of reported total capital and surplus as well as the amount of dividends available for distribution
Reported Capital & Surplus	1.9
Available for Distribution	$ 1.7