Stock-Based Compensation - Stock Options and Appreciation Rights (Details)	6 Months Ended
	Jun. 30, 2021 $ / shares shares
2015 Plan
Stock Options and SARs
Outstanding, beginning balance (in shares)	5,420,463
Granted (in shares)	47,458
Exercised (in shares)	(598,441)
Canceled (in shares)	(50,881)
Outstanding, ending balance (in shares)	4,818,599
Shares exercisable (in shares)	692,187
Shares available for grant (in shares)	2,360,263
Weighted-Average Exercise Price
Outstanding, beginning balance (in dollars per share) | $ / shares	$ 38.05
Granted (in dollars per share) | $ / shares	148.49
Exercised (in dollars per share) | $ / shares	44.14
Canceled (in dollars per share) | $ / shares	121.33
Outstanding, ending balance (in dollars per share) | $ / shares	37.50
Shares exercisable (in dollars per share) | $ / shares	$ 70.17
2005 Plan
Stock Options and SARs
Outstanding, beginning balance (in shares)	214,186
Granted (in shares)	0
Exercised (in shares)	(35,401)
Canceled (in shares)	0
Outstanding, ending balance (in shares)	178,785
Shares exercisable (in shares)	178,785
Weighted-Average Exercise Price
Outstanding, beginning balance (in dollars per share) | $ / shares	$ 88.11
Granted (in dollars per share) | $ / shares	0
Exercised (in dollars per share) | $ / shares	106.49
Canceled (in dollars per share) | $ / shares	0
Outstanding, ending balance (in dollars per share) | $ / shares	84.47
Shares exercisable (in dollars per share) | $ / shares	$ 84.47