Stock-Based Compensation - Stock-based compensation expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	$ 475	$ 4,952
Service based awards
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	1,863	3,867
Restricted stock awards - Service based awards
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	0	(33)
Restricted stock units - Service based awards
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	372	1,600
Stock option awards - Service based awards
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	1,491	2,300
Performance based awards
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	(1,388)	1,085
Restricted stock units - Performance based awards
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	(1,148)	642
Stock option awards - Performance based awards
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	$ (240)	$ 443