Long-Term Debt Obligations - Future Payments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Future principal payments of long-term debt
2017	$ 763
2018	1,046
2019	1,002
Total debt	2,811	$ 11,507
Interest expense
Interest expense on notes to former owners	70	25	$ 38
Interest expense on borrowings and unused commitment fees	1,251	692	790
Letter of credit fees	657	719	747
Amortization of debt financing costs	367	317	283
Total	$ 2,345	1,753	$ 1,858
Revolving credit facility
Future principal payments of long-term debt
Total debt		$ 10,000