Restructuring and Other Charges Restructuring Reserve Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Integration-related, legal and other non-recurring expenses		$ 1,035	$ 106	$ 513
Employee-related restructuring expenses		5,504	2,771	3,890
Restructuring Costs and Asset Impairment Charges	$ 1,700	1,743	40	225
Lease abandonment expenses		57	0	$ 392
Restructuring Reserve [Roll Forward]
Balance accrued as of December 31, 2016		1,437
Additions		5,727
Reversals		(166)
Expenditures		(4,224)
Balance accrued as of December 31, 2017	2,774	2,774	1,437
Severance, Payroll Taxes and Other Employee Benefits [Member]
Restructuring Reserve [Roll Forward]
Balance accrued as of December 31, 2016		1,347
Additions		5,670
Reversals		(166)
Expenditures		(4,077)
Balance accrued as of December 31, 2017	2,774	2,774	1,347
Lease Abandonment Charges [Member]
Restructuring Reserve [Roll Forward]
Balance accrued as of December 31, 2016		90
Additions		57
Reversals		0
Expenditures		(147)
Balance accrued as of December 31, 2017	$ 0	$ 0	$ 90