Debt - Future Minimum Principal Payment Obligations (Details) $ in Thousands	Sep. 30, 2018 USD ($)
Long-term Debt, Fiscal Year Maturity [Abstract]
2019	$ 2,000
2020	2,000
2021	2,000
2022	2,000
2023	2,000
Thereafter	188,500
Total outstanding principal balance	198,500
Unamortized deferred financing costs	(2,429)
Long-term debt	$ 196,071