Long-term Debt - Principal Balances under Long-term Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Line of Credit Facility [Line Items]
Total long-term debt	$ 327,760	$ 207,593
Less debt issuance costs	(653)	0
Less current portion	10,000	10,000
Long-term portion	317,760	197,593
Term Loan
Line of Credit Facility [Line Items]
Total long-term debt	147,500	64,962
Revolving Credit Facility
Line of Credit Facility [Line Items]
Total long-term debt	$ 180,913	$ 142,631