Acquisition of Business (Details) - USD ($) $ in Millions	May. 07, 2015	Apr. 30, 2015
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net		$ 71.0
Payments to Acquire Businesses, Gross		71.0
Capital Contribution to Subsidiary	$ 75.0
Investments [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets		187.0
Cash [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets		13.4
Premiums Receivable [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets		44.4
Receivables Other Than Premium Receivables [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets		49.2
Intangible Assets Other Than Intangible Assets Arising from Insurance Contracts Acquired [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets		26.3
Goodwill [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets		6.7
Current Income Tax Asset [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets		1.7
Other Assets Acquired [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets		9.2
Property and Casualty Insurance Reserves [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		(155.8)
Unearned Premiums [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		(72.4)
Current and Deferred Income Taxes [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		(3.9)
Other Liabilities [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		$ (34.8)