Stock-Based Compensation - Changes in Stock Options Outstanding (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2020 $ / shares shares
Number of Options
Outstanding, beginning balance (in shares) | shares	8,410
Exercised (in shares) | shares	(17)
Forfeited (in shares) | shares	(292)
Expired (in shares) | shares	(816)
Outstanding, ending balance (in shares) | shares	7,285
Weighted Average Exercise Price Per Option
Outstanding, beginning (in dollars per share) | $ / shares	$ 32.50
Exercised (in dollars per share) | $ / shares	21.80
Forfeited (in dollars per share) | $ / shares	25.89
Expired (in dollars per share) | $ / shares	33.90
Outstanding, ending (in dollars per share) | $ / shares	$ 32.63
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options exercisable (in shares) | shares	5,882
Options exercisable (in dollars per share) | $ / shares	$ 34.32