Discontinued Operations (Details) - Digital Marketing Business - Discontinued Operations, Held-for-sale - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Jun. 30, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues	$ 84.8	$ 111.7	$ 170.5	$ 219.9
Cost of revenues	65.9	79.3	132.9	157.7
Selling, general and administrative expenses	10.5	7.6	21.6	14.7
Provision for valuation allowance	69.2	0.0	69.2	0.0	$ 0.0
Restructuring expenses	0.0	0.1	0.0	1.5
Total expenses	145.6	87.0	223.7	173.9
(Loss) Earnings before income taxes	(60.8)	24.7	(53.2)	46.0
Provision from income taxes	15.1	(6.4)	13.2	(11.9)
(Loss) Earnings from discontinued operations, net of taxes	$ (45.7)	$ 18.3	$ (40.0)	$ 34.1