Fair Value Measures - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Increase (decrease) in fair value	$ (709)	$ (17)	$ 46	$ 101	$ (167)
Interest expense	$ 38	$ 38	$ 112	$ 112