Stock-Based Compensation - Share-based compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share based compensation expense	$ 250	$ 877	$ (276)	$ 3,895
Service based awards
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share based compensation expense	252	1,099	1,262	3,070
Restricted stock units - service based awards
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share based compensation expense	9	502	243	1,274
Stock option awards - service based awards
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share based compensation expense	243	597	1,019	1,796
Performance based awards
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share based compensation expense	(2)	(222)	(1,538)	825
Restricted stock units - performance based awards
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share based compensation expense	(123)	(332)	(1,148)	469
Stock option awards - performance based awards
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share based compensation expense	$ 121	$ 110	$ (390)	$ 357