Stock-Based Compensation - Summary of Status of Plans (Details)	3 Months Ended
	Mar. 31, 2021 shares
2018 Plan
Summary of Status of Equity-Based Compensation Plans
Awards originally available	2,500,000
Stock options outstanding	656,205
RSUs and cash settled awards vested and released	96,136
Awards available for grant	1,747,659
2014 Plan
Summary of Status of Equity-Based Compensation Plans
Awards originally available	1,500,000
Stock options outstanding	52,500
2009 Plan
Summary of Status of Equity-Based Compensation Plans
Awards originally available	3,400,000
Stock options outstanding	75,200
2004 Plan
Summary of Status of Equity-Based Compensation Plans
Awards originally available	6,500,000
Stock options outstanding	35,952
Directors' Plan
Summary of Status of Equity-Based Compensation Plans
Stock options outstanding	5,522
RSUs | 2018 Plan
Summary of Status of Equity-Based Compensation Plans
Shares outstanding	656,205
RSUs | 2014 Plan
Summary of Status of Equity-Based Compensation Plans
Shares outstanding	52,500
RSUs | 2009 Plan
Summary of Status of Equity-Based Compensation Plans
Shares outstanding	75,200
RSUs | 2004 Plan
Summary of Status of Equity-Based Compensation Plans
Shares outstanding	35,952
RSUs | Directors' Plan
Summary of Status of Equity-Based Compensation Plans
Shares outstanding	5,522