Share-Based Compensation - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Capitalized share-based compensation costs	$ 0	$ 0	$ 0
Repurchase of common stock for employee tax withholding obligations amount	$ 1,688,000	$ 3,046,000	$ 1,209,000
Recognition period of unrecognized cost	2 years 1 month 6 days
Requisite service period	2 years
Total unrecognized compensation cost related to non-vested stock option awards	$ 1,400,000
Granted, Shares	204,150	0	0
Minimum [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share based compensation arrangement performance period	1 year
Maximum
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share based compensation arrangement performance period	3 years 4 months 24 days
Performance Unit Incentive Plan ("PUP")
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Shares available for grant	0	3,400,000	0
Awards with grant date fair value during the period	$ 4,800,000
Stock value payable	1,800,000
Liability awards recorded	800,000	$ 5,300,000
Payments to employees	2,600,000	5,600,000	$ 5,900,000
Repurchase of common stock for employee tax withholding obligations amount		$ 1,500,000
Repurchase of common stock for employee tax withholding obligations amount, shares		25,771
Restricted Stock Awards And Restricted Stock Units
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Payments to employees	200,000	$ 600,000	200,000
Liabilities related to restricted stock	200,000	400,000
Paid to employees as shares	2,000,000.0	200,000
Restructuring Charges
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation before income tax benefit	$ 0	100,000	0
2017 Plan
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Useful Term of the plan	10 years
Common stock shares issuable	1,750,000,000
Shares available for grant	1,081,404,000
2007 Plan
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Award vesting period	3 years
2007 Plan | Restricted Stock Awards And Restricted Stock Units
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Repurchase of common stock for employee tax withholding obligations amount	$ 1,700,000	$ 1,500,000	$ 1,200,000
Repurchase of common stock for employee tax withholding obligations amount, shares	42,185,000	24,995,000	22,358,000
Unamortized cost	$ 4,200,000
Recognition period of unrecognized cost	1 year 3 months 18 days