Long-term Debt - Principal Balances under Long-term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Line of Credit Facility [Line Items]
Total long-term debt	$ 228,402	$ 207,593
Less current portion	10,000	10,000
Long-term portion	218,402	197,593
Term Loan
Line of Credit Facility [Line Items]
Total long-term debt	62,462	64,962
Revolving Credit Facility
Line of Credit Facility [Line Items]
Total long-term debt	$ 165,940	$ 142,631