Note 12 - Equity Compensation Plans (Details Textual) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended
	Jan. 31, 2024	Mar. 31, 2024	Mar. 31, 2023
Proceeds from Stock Options Exercised		$ 28.2	$ 58.4
Nonqualified Stock Option, Contractual Term (Year)		10 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)		4 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)		199,866
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)		5 years 10 months 24 days
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term (Year)		5 years 1 month 6 days
Unrecognized Compensation Cost Related to Nonvested Share Based Compensation Arrangements		$ 113.5
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)		2 years 8 months 1 day
Minimum [Member]
Performance Share Units, Percnetage of Target Levels	0.00%
Maximum [Member]
Performance Share Units, Percnetage of Target Levels	200.00%
Performance Shares [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)		3 years
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Per Award (in shares)		1
Share-based Compensation Arrangement by Share-based Payment Award, Target Levels		100.00%
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)		47,838
Performance Shares [Member] | Key Employees [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)	47,838
Performance Shares [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Target Levels		0.00%
Performance Shares [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Target Levels		200.00%
Nonqualified Stock Option [Member] | Key Employees [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)	199,776
Restricted Stock [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)	4 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)		129,964
Restricted Stock [Member] | Key Employees [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)	129,789
TSR Based PSUs [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)	29,929
ROIC Based PSUs [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)	17,909
Employee Stock Purchase Plan [Member] | UK Sharesave Plan [Member]
Common Stock, Capital Shares Reserved for Future Issuance (in shares)		442,118
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)		3 years
Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Purchase Date		5.00%
Employee Stock Purchase Plan [Member] | US ESPP [Member]
Common Stock, Capital Shares Reserved for Future Issuance (in shares)		1,172,243
Share-Based Compensation Arrangement by Share-Based Payment Award, Shares Issued in Period (in shares)		5,015	5,661
Value of Common Stock Issued to Employees Per Share (in dollars per share)		$ 223.94	$ 182.24
The 2021 Incentive Plan [Member]
Common Stock, Capital Shares Reserved for Future Issuance (in shares)		12,819,287