Restructuring and Other Charges - Restructuring Reserve Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Restructuring Cost and Reserve [Line Items]
Severance Costs	$ (86)		$ 1,215	$ 778	$ 1,257
Business Combination, Integration Related Costs	1,375		20	1,892	213
Restructuring and Business Combination Related Expenses, Facility Reductions	0	$ 190	$ 0	190	$ 0
Balance accrued as of December 31, 2013		2,774		2,774
Restructuring Charges				1,159
Restructuring Reserve, Accrual Adjustment				(191)
Expenditures				(3,398)
Balance accrued as of September 30, 2014	344			344
Severance, Payroll Taxes and Other Employee Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Balance accrued as of December 31, 2013		2,774		2,774
Restructuring Charges				969
Restructuring Reserve, Accrual Adjustment				(191)
Expenditures				(3,357)
Balance accrued as of September 30, 2014	195			195
Lease Abandonment Charges [Member]
Restructuring Cost and Reserve [Line Items]
Balance accrued as of December 31, 2013		$ 0		0
Restructuring Charges				190
Restructuring Reserve, Accrual Adjustment				0
Expenditures				(41)
Balance accrued as of September 30, 2014	$ 149			$ 149