Stockholders' Equity - Summary of activity under stock-based incentive plans (Details) - Stock incentive plan - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Summary of the activity under the incentive plans
Share-based awards, beginning of period (in shares)	1,778,308	1,739,258	1,766,061	1,754,066
Granted (in shares)	0	188	203,701	79,025
Vested (in shares)	0	0	(191,454)	(93,645)
Forfeited (in shares)	(2,957)	0	(2,957)	0
Share-based awards, end of period (in shares)	1,775,351	1,739,446	1,775,351	1,739,446
Restricted stock
Summary of the activity under the incentive plans
Shares withheld to pay estimated withholding taxes (in shares)			51,972	23,563