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Share-Based Compensation - Share-based compensation expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense	$ 69,892	$ 63,848	$ 55,935
Share based compensation expense, net of tax	60,345	55,502	49,179
Options and SARs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense	11,744	12,866	16,272
Share based compensation expense, net of tax	10,388	11,450	14,894
Restricted Common Shares And Restricted Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense	41,284	38,988	34,025
Share based compensation expense, net of tax	34,599	32,999	29,044
Performance Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense	14,729	8,949	4,414
Share based compensation expense, net of tax	13,380	8,295	4,127
Employee Share Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense	2,135	3,045	1,224
Share based compensation expense, net of tax	$ 1,978	$ 2,758	$ 1,114

X

- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
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-SubTopic 10
-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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