Note 3 - Share-based Compensation - Components of Share-based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Restricted Stock Units (RSUs) [Member]
Pretax compensation expense	$ 14,920	$ 12,214	$ 27,895	$ 22,993
Tax benefit	3,730	3,078	6,974	5,795
Share unit expense, net of tax	11,190	9,136	20,921	17,198
Performance Shares [Member]
Pretax compensation expense	5,523	4,284	11,689	8,473
Tax benefit	1,381	1,080	2,922	2,135
Share unit expense, net of tax	$ 4,142	$ 3,204	$ 8,767	$ 6,338

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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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