Share-Based Compensation - Option Rollforward (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Roll [Forward]
Beginning Balance | shares	122,072
Options Granted | shares	51,610
Options Exercised | shares	(28,535)
Options Forfeited | shares	(735)
Ending Balance | shares	144,412
Options Expected to Vest | shares	84,839
Options Exerciseable | shares	59,573
Weighted Average Exercise Price [Abstract]
Outstanding at beginning of year | $ / shares	$ 116.39
Options Granted | $ / shares	154.92
Options Exercised | $ / shares	80.22
Options Forfeited | $ / shares	147.01
Outstanding at End of Period | $ / shares	137.15
Options Expected to Vest | $ / shares	151.12
Options Exerciseable | $ / shares	$ 117.27
Share Based Compensation Arrangement By Share Based Payment Award Options Additional Disclosures [Abstract]
Weighted Average Remaining Contractual Term, Outstanding	4 years 9 months 18 days
Weighted Average Remaining Contractual Term, Expected to Vest	5 years 7 months 6 days
Weighted Average Remaining Contractual Term, Exercisable	3 years 8 months 12 days
Outstanding Options, Intrinsic Value | $	$ 4,066
Expected to Vest Options, Intrinsic Value | $	1,204
Exercisable Options, Intrinsic Value | $	$ 2,862