Stockholders' Equity - Stock Compensation - Nonvested - Unrecognized Stock Compensation Expense (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
Restricted Stock Awards
Stock Compensation
Unrecognized compensation expense, nonvested	$ 3.5
Unrecognized compensation expense, period of recognition	2 years 6 months 25 days
Restricted Stock Units (RSUs)
Stock Compensation
Unrecognized compensation expense, nonvested	$ 18.3
Unrecognized compensation expense, period of recognition	1 year 11 months 19 days
Performance Based Restricted Stock Units ("PSUs")
Stock Compensation
Unrecognized compensation expense, nonvested	$ 9.2
Unrecognized compensation expense, period of recognition	1 year 11 months 15 days