Stock-Based Compensation - Stock Options and Appreciation Rights (Details)	9 Months Ended
	Sep. 30, 2021 $ / shares shares
2015 Plan
Stock Options and SARs
Outstanding, beginning balance (in shares)	5,420,463
Granted (in shares)	73,091
Exercised (in shares)	(1,420,550)
Canceled (in shares)	(80,799)
Outstanding, ending balance (in shares)	3,992,205
Shares exercisable (in shares)	1,286,515
Shares available for grant (in shares)	3,788,799
Weighted-Average Exercise Price
Outstanding, beginning balance (in usd per share) | $ / shares	$ 38.05
Granted (in usd per share) | $ / shares	176.39
Exercised (in usd per share) | $ / shares	32.49
Canceled (in usd per share) | $ / shares	119.36
Outstanding, ending balance (in usd per share) | $ / shares	40.92
Shares exercisable (in usd per share) | $ / shares	$ 48.62
2005 Plan
Stock Options and SARs
Outstanding, beginning balance (in shares)	214,186
Granted (in shares)	0
Exercised (in shares)	(140,580)
Canceled (in shares)	0
Outstanding, ending balance (in shares)	73,606
Shares exercisable (in shares)	73,606
Weighted-Average Exercise Price
Outstanding, beginning balance (in usd per share) | $ / shares	$ 88.11
Granted (in usd per share) | $ / shares	0
Exercised (in usd per share) | $ / shares	80.03
Canceled (in usd per share) | $ / shares	0
Outstanding, ending balance (in usd per share) | $ / shares	103.56
Shares exercisable (in usd per share) | $ / shares	$ 103.56