Fair Value Measurements - (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended		12 Months Ended
	Sep. 30, 2014 Rate	Sep. 30, 2013	Dec. 31, 2013 Rate	Jun. 30, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proceeds from Sale of Available-for-sale Securities, Debt	$ 475
Financial Instruments, Owned, State and Municipal Government Obligations, at Fair Value	114,857		86,305
Available-for-sale Securities, Failed Auction, Value	0		277
Foreign Currency Contract, Asset, Fair Value Disclosure	138		6
Assets, Fair Value Disclosure	114,995		86,588
Business Combination, Contingent Consideration, Liability	(4,903)		5,208
Liabilities, Fair Value Disclosure	4,903		5,208
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value			277	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		198
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases, Sales, Issues, Settlements		0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Sales, Issues, Settlements		(475)
Fair Value, Level 3 Transfers out, Description	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	4,903		5,208
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	(111)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	(194)
Convertible Debt	53,997		51,751
Long-term Debt, Fair Value	59,832		59,340
Fair Value Inputs Discount Rate 2	4.40%		4.20%
Fair Value Inputs Discount Rate 3	6.70%
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
Available-for-sale Securities, Failed Auction, 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	114,857		86,305
Available-for-sale Securities, Failed Auction, Value	0		0
Foreign Currency Contract, Asset, Fair Value Disclosure	138		6
Assets, Fair Value Disclosure	114,995		86,311
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
Available-for-sale Securities, Failed Auction, Value	0		277
Foreign Currency Contract, Asset, Fair Value Disclosure	0		0
Assets, Fair Value Disclosure	0		277
Business Combination, Contingent Consideration, Liability	(4,903)		5,208
Liabilities, Fair Value Disclosure	$ 4,903		$ 5,208