Share Incentive Plans - Summary of Weighted Average Fair Value for Each Restricted Share/Unit (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restricted Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average fair value per restricted share	$ 77.44	$ 73.96	$ 62.25
LTI Awards [Member] | Restricted Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average fair value per restricted share	75.89	65.36	63.86
LTI Awards [Member] | Restricted Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average fair value per restricted share	$ 72.69	$ 63.12	$ 62.20