Restructuring and Related Activities - Restructuring Accrual Activities (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 2.8	$ 3.7	$ 3.5	$ 7.2
Restructuring Reserve [Roll Forward]
Severance and other restructuring reserve, beginning balance			3.8
Restructuring charges			7.2
Payments			(3.6)
Severance and other restructuring reserve, ending balance	7.4		7.4
Restructuring Reserve, Accrual Adjustment	0.9
Expected cost remaining	0.2		0.2
Severance Pay and Contract Termination and Other Costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	2.2	3.9	7.2	8.6
Severance Pay and Benefits
Restructuring Reserve [Roll Forward]
Severance and other restructuring reserve, beginning balance			3.4
Restructuring charges			5.8
Payments			(3.6)
Severance and other restructuring reserve, ending balance	5.6		5.6
Contract Termination and Other Costs
Restructuring Reserve [Roll Forward]
Severance and other restructuring reserve, beginning balance			0.4
Restructuring charges			1.4
Payments			0.0
Severance and other restructuring reserve, ending balance	1.8		1.8
Cost of Goods Sold, Restructuring Charges [Member] | Severance Pay and Contract Termination and Other Costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	(0.6)		3.7
Operating Expense [Member] | Severance Pay and Contract Termination and Other Costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 2.8		$ 3.5
Audience, Inc. [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges		3.9		8.6
Audience, Inc. [Member] | Cost of Goods Sold, Restructuring Charges [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges		0.2		1.4
Audience, Inc. [Member] | Operating Expense [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 3.7		$ 7.2