Stock-Based Compensation - Stock Option Summary (Details) - Share-based Payment Arrangement, Option [Member] - USD ($) $ / shares in Units, shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, beginning balance (in shares)	458	895	956
Converted upon acquisition (in shares)			42
Granted (in shares)	83	76	122
Exercised (in shares)	(103)	(489)	(152)
Forfeited (in shares)	(5)	(13)	(7)
Expired (in shares)		(11)	(66)
Outstanding, ending balance (in shares)	433	458	895	956
Exercisable, ending balance (in shares)	268
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Outstanding, beginning balance (in dollars per share)	$ 56.38	$ 47.93	$ 47.10
Converted upon acquisition (in dollars per share)			51.86
Granted (in dollars per share)	84.39	76.55	68.21
Exercised (in dollars per share)	53.99	43.55	38.99
Forfeited (in dollars per share)	83.94	67.34	60.03
Expired (in dollars per share)		66.24	95.31
Outstanding, ending balance (in dollars per share)	61.95	$ 56.38	$ 47.93	$ 47.10
Exercisable, ending balance (in dollars per share)	$ 51.85
Outstanding, Weighted Average Remaining Contractual Term	6 years 10 months 24 days	7 years	6 years 2 months 12 days	6 years 3 months 18 days
Exercisable, Weighted Average Remaining Contractual Term	5 years 9 months 18 days
Outstanding, Aggregate Intrinsic Value	$ 14,697,000	$ 12,641,000	$ 4,806,000	$ 21,965,000
Exercised, Aggregate Intrinsic Value	2,061,000	$ 15,759,000	$ 4,520,000
Exercisable, Aggregate Intrinsic Value	$ 11,810,000
Converted upon acquisition, Weighted Average Grant Date Fair Value (in dollars per share)			$ 14.86
Granted, Weighted Average Grant Date Fair Value (in dollars per share)	$ 26.37	$ 26.20	$ 24.29