Acquisitions (Prior Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016	Dec. 30, 2014
Business Acquisition [Line Items]
Reduction in estimated contingent consideration payable	$ (1.1)	$ (19.6)	$ (4.8)	$ (19.5)	$ (4.1)
Selectable Media, Inc.
Business Acquisition [Line Items]
Percentage of voting interests acquired						100.00%
Final payment			4.0
Shape | Selling, general and administrative expenses
Business Acquisition [Line Items]
Reduction in estimated contingent consideration payable			2.0	$ 1.3	$ 4.9
Contingent consideration arrangements			$ 19.2