SCHEDULE II CONDENSED FINANCIAL INFORMATION OF REGISTRANT PARENT COMPANY ONLY (STATEMENTS OF INCOME) (Parenthetical) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Financial Statements Captions [Line Items]
Income from discontinued operation, income tax (expense) benefit		$ (0.2)	$ (0.1)	$ 1.7
Chaucer [Member]
Condensed Financial Statements Captions [Line Items]
Income from discontinued operation, income tax (expense) benefit	[1]	$ (42.5)

[1] The income tax expense represents the current tax obligation on the sale and the derecognition of deferred tax assets that are no longer likely to be realized.