Property and Casualty Insurance Reserves (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Beginning Property and Casualty Insurance Reserves: [Abstract]
Gross of Reinsurance and Indemnification at Beginning of Year	$ 862,800,000	$ 733,900,000	$ 843,500,000
Less Reinsurance Recoverables and Indemnification at Beginning of Year	108,300,000
Property and Casualty Insurance Reserves, Net of Reinsurance and Indemnification at Beginning of Year	810,800,000	679,000,000	780,100,000
Property and Casualty Insurance Reserves Acquired, Net of Reinsurance and Indemnification				$ 0	$ 125,400,000	$ 0
Incurred Losses and LAE related to:
Prior Years - Incurred Losses and LAE	(20,700,000)	(20,100,000)	(57,100,000)
Total Incurred Losses and LAE	1,337,900,000	1,103,200,000	908,300,000
Paid Losses and LAE related to:
Prior Years - Paid Losses and LAE	436,500,000	373,600,000	369,600,000
Total Paid Losses and LAE	1,267,500,000	1,096,800,000	1,009,400,000
Property and Casualty Insurance Reserves, Net of Reinsurance and Indemnification at End of Year	810,800,000	679,000,000	780,100,000	$ 881,200,000	$ 810,800,000	$ 679,000,000
Plus Reinsurance and Indemnification Recoverables at End of Year	106,400,000	108,300,000
Property and Casualty Insurance Reserves, Gross of Reinsurance at End of Year	931,400,000	862,800,000	733,900,000
Continuing Operations [Member]
Incurred Losses and LAE related to:
Current Year - Incurred Losses and LAE	1,358,600,000	1,123,300,000	965,400,000
Prior Years - Incurred Losses and LAE	(14,400,000)	(11,500,000)	(53,500,000)
Paid Losses and LAE related to:
Current Year - Paid Losses and LAE	831,000,000	723,200,000	639,800,000
Prior Years - Paid Losses and LAE	431,900,000	366,200,000	360,400,000
Discontinued Operations [Member]
Incurred Losses and LAE related to:
Prior Years - Incurred Losses and LAE	(6,300,000)	(8,600,000)	(3,600,000)
Paid Losses and LAE related to:
Prior Years - Paid Losses and LAE	4,600,000	7,400,000	9,200,000
Alliance United [Member]
Incurred Losses and LAE related to:
Prior Years - Incurred Losses and LAE		7,700,000
Catastrophe [Member]
Incurred Losses and LAE related to:
Prior Years - Incurred Losses and LAE	(19,300,000)	(7,800,000)	(14,700,000)
Total Incurred Losses and LAE	95,800,000	60,500,000	83,800,000
Property and Casualty Insurance [Member]
Beginning Property and Casualty Insurance Reserves: [Abstract]
Less Reinsurance Recoverables and Indemnification at Beginning of Year	52,000,000	54,900,000	63,400,000
Paid Losses and LAE related to:
Plus Reinsurance and Indemnification Recoverables at End of Year	50,200,000	52,000,000	54,900,000
Property and Casualty, Personal Insurance Product Line [Member]
Incurred Losses and LAE related to:
Prior Years - Incurred Losses and LAE	(16,800,000)	(13,300,000)	(50,900,000)
Property and Casualty, Commercial Insurance Product Line [Member]
Incurred Losses and LAE related to:
Prior Years - Incurred Losses and LAE	(3,900,000)	(6,800,000)	(6,200,000)
Property and Casualty, Commercial Insurance Product Line [Member] | Continuing Operations [Member]
Incurred Losses and LAE related to:
Prior Years - Incurred Losses and LAE	2,400,000	1,800,000	(2,600,000)
Property and Casualty, Commercial Insurance Product Line [Member] | Discontinued Operations [Member]
Incurred Losses and LAE related to:
Prior Years - Incurred Losses and LAE	(6,300,000)	(8,600,000)	(3,600,000)
Personal Automobile [Member]
Incurred Losses and LAE related to:
Prior Years - Incurred Losses and LAE	11,300,000	(1,800,000)	(31,600,000)
Homeowners [Member]
Incurred Losses and LAE related to:
Prior Years - Incurred Losses and LAE	(20,000,000)	(10,800,000)	(14,800,000)
Homeowners [Member] | Catastrophe [Member]
Incurred Losses and LAE related to:
Prior Years - Incurred Losses and LAE	(16,800,000)
Other Personal Lines [Member]
Incurred Losses and LAE related to:
Prior Years - Incurred Losses and LAE	$ (8,100,000)	(700,000)	$ (4,500,000)
Property and Casualty, Personal Insurance Product Line, Excluding Alliance United [Member]
Incurred Losses and LAE related to:
Prior Years - Incurred Losses and LAE		$ (21,000,000)