Fair Values of Financial Instruments - Details of Book Value and Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 60,055	$ 38,931
Other investments	160	249
Installment receivables, net of reserves	1,793	1,911
Long-term debt (including current maturities of long-term debt)	(47,120)	(20,331)
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	60,055	38,931
Other investments	160	249
Installment receivables, net of reserves	1,793	1,911
Long-term debt (including current maturities of long-term debt)	(47,369)	(20,248)
Foreign exchange forward | Other Current Assets | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	4,143	520
Foreign exchange forward | Other Current Assets | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative assets	4,143	520
Foreign exchange forward | Accrued Expenses | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	(2,014)	(2,526)
Foreign exchange forward | Accrued Expenses | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative liabilities	$ (2,014)	$ (2,526)