Share-Based Compensation - Summary of Share-Based Compensation (income) expense (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Summary of share-based compensation expense
Share-based compensation expense before income tax		$ 2,653	$ 7,190	$ 4,870
Income tax benefit	[1]		(2,241)	(1,227)
Share-based compensation expense, net of income tax		2,653	4,949	3,643
Performance Unit Incentive Plan ("PUP")
Summary of share-based compensation expense
Share-based compensation expense before income tax		(2,187)	3,990	2,260
Restricted Stock Awards And Restricted Stock Units
Summary of share-based compensation expense
Share-based compensation expense before income tax		4,523	$ 3,200	$ 2,610
Stock Options
Summary of share-based compensation expense
Share-based compensation expense before income tax		$ 317

[1] There was no income tax benefit for the year ended 2020 due to the valuation allowance on our deferred tax assets. Refer to Note 17 – Income Taxes.