Fair Value Measurements - (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016	Jul. 15, 2016	Jul. 25, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments, Owned, State and Municipal Government Obligations, at Fair Value	$ 90,403		$ 87,029
Financial Instruments, Owned, Corporate Equities, at Fair Value	841		843
Foreign Currency Contract, Asset, Fair Value Disclosure	94		312
Assets, Fair Value Disclosure	91,338		88,184
Business Combination, Contingent Consideration, Liability	3,025		3,251
Liabilities, Fair Value Disclosure	$ 3,025		3,251
Fair Value Inputs Discount Rate 3	8.60%	9.10%
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	$ 3,025		3,251
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases	132
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	$ (358)
Fair Value, Level 3 Transfers out, Description	0
Convertible Debt				$ 60,000	$ 60,000
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		0
Foreign Currency Contract, Asset, Fair Value Disclosure	0		0
Assets, Fair Value Disclosure	0		0
Business Combination, Contingent Consideration, Liability	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	90,403		87,029
Financial Instruments, Owned, Corporate Equities, at Fair Value	841		843
Foreign Currency Contract, Asset, Fair Value Disclosure	94		312
Assets, Fair Value Disclosure	91,338		88,184
Business Combination, Contingent Consideration, Liability	0		0
Liabilities, Fair Value Disclosure	0		0
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		0
Foreign Currency Contract, Asset, Fair Value Disclosure	0		0
Assets, Fair Value Disclosure	0		0
Business Combination, Contingent Consideration, Liability	3,025		3,251
Liabilities, Fair Value Disclosure	$ 3,025		$ 3,251