Discontinued Operations - Reconciliation of Operations (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Other income (expense):
Earnings from discontinued operations attributable to the Company	$ 0.0	$ 0.0	$ 147.7	$ 2.0
OneDigital | Disposed of by Sale
Revenues:
Other operating revenue		37.0	80.9	109.8
Total operating revenues		37.0	80.9	109.8
Operating expenses:
Personnel costs		23.8	56.9	69.1
Depreciation and amortization		4.7	8.8	13.2
Other operating expenses		7.1	11.3	20.5
Total operating expenses		35.6	77.0	102.8
Operating income		1.4	3.9	7.0
Other income (expense):
Interest expense		(1.3)	(2.9)	(3.5)
Realized gains and (losses), net		0.0	276.0	0.0
Total other expense		(1.3)		(3.5)
Total other income			273.1
Earnings from discontinued operations before income taxes		0.1	277.0	3.5
Income tax expense		0.1	129.3	1.5
Earnings from discontinued operations attributable to the Company		0.0	147.7	2.0
Cash flow from discontinued operations data:
Net cash provided by operations		7.2	17.3	22.2
Net cash used in investing activities		$ (12.3)	$ (27.3)	$ (32.3)