Fair Value Measurements - (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2015 Rate	Dec. 31, 2014 Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Instruments, Owned, State and Municipal Government Obligations, at Fair Value	$ 123,045	$ 113,871
Foreign Currency Contract, Asset, Fair Value Disclosure	144	222
Assets, Fair Value Disclosure	123,189	114,093
Business Combination, Contingent Consideration, Liability	4,668	5,064
Liabilities, Fair Value Disclosure	4,668	5,064
Fair Value, Level 3 Transfers out, Description	0
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	4,668	5,064
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	(396)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	0
Convertible Debt	55,584	54,773
Long-term Debt, Fair Value	59,520	59,916
Fair Value Inputs Discount Rate 2	5.00%	5.00%
Fair Value Inputs Discount Rate 3	8.80%
Long-term Debt, Contingent Payment of Principal or Interest	0	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
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	123,045	113,871
Foreign Currency Contract, Asset, Fair Value Disclosure	144	222
Assets, Fair Value Disclosure	123,189	114,093
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
Foreign Currency Contract, Asset, Fair Value Disclosure	0	0
Assets, Fair Value Disclosure	0	0
Business Combination, Contingent Consideration, Liability	4,668	5,064
Liabilities, Fair Value Disclosure	$ 4,668	$ 5,064