Share-Based Compensation - Stock Options Unvested (Details) - Key Officer Director and Managerial Employee Stock Options [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2019
Unvested stock options
Granted (in shares)	1
Weighted-Average Grant-Date Fair Value
Granted (in dollars per share)	$ 72.69	$ 53.50
Total fair value of option vested during the period	$ 0.1	$ 0.2