Fair Value Measurements Additional Information (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt and Capital Lease Obligations	$ 21,190
Defined Benefit Plan, Benefit Obligation	4,264
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Convertible Debt, Fair Value Disclosures	143,500	$ 123,100
Debt and Capital Lease Obligations	21,200
TVN [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Voluntary Departure Plan, Liability	$ 9,600