Stock-Based Compensation - Stock Appreciation Rights Award Activity (Details) - Stock Appreciation Rights (SARs) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards, expiration period	10 years
SARs Activity [Roll Forward]
Outstanding, beginning (in shares)	35,993	39,819	51,368
Granted (in shares)	3,272	3,364	3,480
Exercised (in shares)	(11,261)	(6,790)	(14,629)
Forfeited (in shares)	(325)	(400)	(400)
Outstanding, ending (in shares)	27,679	35,993	39,819
Exercisable (in shares)	27,182	27,781	30,285
SARs, Weighted Average Exercise Price [Roll Forward]
Outstanding, beginning (in dollars per share)	$ 52.36	$ 46.48	$ 38.55
Granted (in dollars per share)	190.97	102.51	89.64
Exercised (in dollars per share)	35.37	42.08	28.45
Forfeited (in dollars per share)	71.43	63.43	63.43
Outstanding, ending (in dollars per share)	75.43	52.36	46.48
Exercisable (in dollars per share)	$ 40.23	$ 40.73	$ 36.91