Share-Based Compensation - Expense Table (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 2,355	$ 2,991	$ 6,134	$ 7,673
Stock Options [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	332	353	640	785
Non-vested stock awards and restricted stock units [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	1,290	1,259	2,686	2,523
Non-elective and elective 401(k) matching contribution in stock [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	0	1,162	1,553	1,162
Director stock ownership plan [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	216	54	419	94
Performance Stock Units [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	517	280	836	280
Annual Incentive Plan [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 0	$ (117)	$ 0	$ 2,829