Restructuring and Other Charges - Restructuring Reserve Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Restructuring Cost and Reserve [Line Items]
Severance Costs	$ 23	$ 1,061	$ 801	$ 2,318
Business Combination, Integration Related Costs	1,107	226	2,999	439
Restructuring and Business Combination Related Expenses, Facility Reductions	0	$ 57	190	$ 57
Balance accrued as of December 31, 2013			2,774
Restructuring Charges			1,175
Restructuring Reserve, Accrual Adjustment			(192)
Expenditures			(3,546)
Balance accrued as of September 30, 2014	211		211
Severance, Payroll Taxes and Other Employee Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Balance accrued as of December 31, 2013			2,774
Restructuring Charges			985
Restructuring Reserve, Accrual Adjustment			(192)
Expenditures			(3,473)
Balance accrued as of September 30, 2014	94		94
Lease Abandonment Charges [Member]
Restructuring Cost and Reserve [Line Items]
Balance accrued as of December 31, 2013			0
Restructuring Charges			190
Restructuring Reserve, Accrual Adjustment			0
Expenditures			(73)
Balance accrued as of September 30, 2014	$ 117		$ 117