Stockholders' Equity, Preferred and Common Stock (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Common Stock [Abstract]
Common stock, shares authorized to issue (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	140,365,594	140,339,615
Common stock, shares outstanding (in shares)	140,365,594	140,339,615
Net proceeds from stock option exercises, vesting of restricted stock units, and ESPP purchases	$ 52,036	$ 119,657	$ 27,900
Preferred Stock [Member]
Preferred Stock [Abstract]
Preferred stock, shares authorized (in shares)	15,000,000
Preferred stock, shares outstanding (in shares)	0
Series C Junior Participating Preferred Stock [Member]
Preferred Stock [Abstract]
Preferred stock, shares issued (in shares)	0
Preferred stock, shares outstanding (in shares)	0
Common Stock [Member]
Common Stock [Abstract]
Common stock, shares authorized to issue (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	140,400,000	140,300,000
Common stock, shares outstanding (in shares)	140,400,000	140,300,000
Common shares reserved for future issuance (in shares)	26,100,000
Number of shares issued for stock option exercises, vesting of restricted stock units, and ESPP purchases (in shares)	1,700,000	3,100,000	1,500,000
Net proceeds from stock option exercises, vesting of restricted stock units, and ESPP purchases	$ 52,000	$ 119,700	$ 27,900