Fair Value Measurements - Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	May 29, 2020	Oct. 22, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, fair value	$ 161,800	$ 154,900
Debt, carrying value	$ 158,934	$ 147,800
Seller Warrants
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Outstanding warrants (in shares)	12,721,901	12,721,901	12,700,000	12,721,901