Fair Value Measurements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Jul. 15, 2016	Dec. 31, 2014	Jul. 25, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Document Period End Date	Dec. 31, 2016
Debt Instrument, Face Amount	$ 0	$ 60,000	$ 60,000		$ 60,000
Convertible Debt, Current	0	57,846
Financial Instruments, Owned, State and Municipal Government Obligations, at Fair Value	87,029	116,089
Financial Instruments, Owned, Corporate Equities, at Fair Value	843
Foreign Currency Contracts, Liability, Fair Value Disclosure	312	835
Assets, Fair Value Disclosure	88,184	116,924
Business Acquisition Contingent Consideration at Fair Value, Liabilities	3,251	3,703
Liabilities, Fair Value Disclosure	3,251	$ 3,788
Fair Value Input Discount Rate 3		9.10%
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value		$ 3,251		$ 3,703
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		170
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements		(622)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3		0
Convertible Debt, Noncurrent		57,846
Convertible Debt, Fair Value Disclosures		$ 60,630
Fair Value Inputs Discount Rate 2		5.00%
Long-term Debt, Contingent Payment of Principal or Interest		0
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments, Owned, State and Municipal Government Obligations, at Fair Value	0	$ 0
Financial Instruments, Owned, Corporate Equities, at Fair Value	0
Foreign Currency Contracts, Liability, Fair Value Disclosure	0	0
Assets, Fair Value Disclosure	0	0
Business Acquisition Contingent Consideration at Fair Value, Liabilities	0	0
Liabilities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments, Owned, State and Municipal Government Obligations, at Fair Value	87,029	116,089
Financial Instruments, Owned, Corporate Equities, at Fair Value	843
Foreign Currency Contracts, Liability, Fair Value Disclosure	312	835
Assets, Fair Value Disclosure	88,184	116,924
Business Acquisition Contingent Consideration at Fair Value, Liabilities	0	0
Liabilities, Fair Value Disclosure	0	85
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments, Owned, State and Municipal Government Obligations, at Fair Value	0	0
Financial Instruments, Owned, Corporate Equities, at Fair Value	0
Foreign Currency Contracts, Liability, Fair Value Disclosure	0	0
Assets, Fair Value Disclosure	0	0
Business Acquisition Contingent Consideration at Fair Value, Liabilities	3,251	3,703
Liabilities, Fair Value Disclosure	$ 3,251	$ 3,703