Long-term Debt, Line of Credit and Derivatives - Obligations under Debt Arrangements (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Principal, current	$ 13,500	$ 19,813
Principal	82,125	104,563
Deferred Issuance Costs, current	(422)	(625)
Deferred Issuance Costs	(2,566)	(3,298)
Net Value, current	13,078	19,188
Net Value, long-term	66,481	82,077
Total debt	79,559	101,265
Revolving line of credit | Line of Credit
Debt Instrument [Line Items]
Principal, current	0	8,000
Deferred Issuance Costs, current	0	(252)
Net Value, current	0	7,748
Term loan - current | Loans Payable
Debt Instrument [Line Items]
Principal, current	13,500	11,813
Deferred Issuance Costs, current	(422)	(373)
Net Value, current	13,078	11,440
Term loan - long-term | Loans Payable
Debt Instrument [Line Items]
Principal, long-term	68,625	84,750
Deferred Issuance Costs, long-term	(2,144)	(2,673)
Net Value, long-term	$ 66,481	$ 82,077