Note 15 - Stock-based Compensation (Details Textual) - USD ($) $ / shares in Units, $ in Millions							1 Months Ended				3 Months Ended	12 Months Ended
	Dec. 31, 2020	Nov. 03, 2020	Jul. 01, 2020	Jun. 15, 2020	May 12, 2020	May 07, 2018	Nov. 30, 2022	Jun. 30, 2022	Nov. 30, 2021	May 31, 2012	Mar. 31, 2022	Dec. 31, 2022		Dec. 31, 2021		Dec. 31, 2020
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total												$ 14.9
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)												1 year 3 months 14 days
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Annual Forfeiture Rate												11.50%		11.10%		10.80%
Increase (Decrease) In Stock Based Compensation Expense Due To Forfeitures, Percent												3.60%		2.80%		0.90%
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Dividends Growth Rate												20.00%
Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Weighted Average Expected Dividend Rate												0.70%
Share Price (in dollars per share)												$ 86.48		$ 79.30
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number (in shares)												749,101		881,393
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period, Intrinsic Value												$ 21.9		$ 6.1
Weighted Average [Member]
Share Price (in dollars per share)												$ 82.8		$ 78.4
2012 Stock Incentive Plan [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)										6 years
2012 Stock Incentive Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)										10 years
2012 Stock Incentive Plan [Member] | Stock Options And Stock Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)										4,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)										1 year
2012 Stock Incentive Plan [Member] | Stock Options And Stock Appreciation Rights [Member] | Share-Based Payment Arrangement, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage										50.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)										2 years
2012 Stock Incentive Plan [Member] | Stock Options And Stock Appreciation Rights [Member] | Share-Based Payment Arrangement, Tranche One [Member] | Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage										100.00%
2012 Stock Incentive Plan [Member] | Stock Options And Stock Appreciation Rights [Member] | Share-Based Payment Arrangement, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage										25.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)										3 years
2012 Stock Incentive Plan [Member] | Stock Options And Stock Appreciation Rights [Member] | Share-Based Payment Arrangement, Tranche Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)										4 years
2012 Stock Incentive Plan [Member] | Stock Options And Stock Appreciation Rights [Member] | Share-based Compensation Award, Tranche Four [Member] | Senior Management [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage										25.00%
2012 Stock Incentive Plan [Member] | Share-Based Payment Arrangement, Option [Member] | Non Employee Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)										1 year
The 2018 Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)						5,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)								1 year
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized (in shares)								1,700,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares)												3,562,094
The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)		1 year
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)		6 years
The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)						6 years
The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)						10 years
The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member] | Share-Based Payment Arrangement, Tranche One [Member] | Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage						100.00%
The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member] | Share-Based Payment Arrangement, Tranche One [Member] | Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage						50.00%
The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member] | Share-Based Payment Arrangement, Tranche Two [Member] | Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage						25.00%
The 2018 Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)									1 year
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)	$ 89.15	$ 67.13	$ 62.3	$ 68.0	$ 67.2				$ 76.2			$ 0	[1]	$ 0	[1]	$ 0	[1]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)	2,103		6,020	11,068	6,142							109,000	[1]	12,000	[1]	35,000	[1]
The 2018 Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member] | Director [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Granted (in shares)							19,750		11,804
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)							$ 89
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)		10,010
The 2018 Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member] | Director [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)							2 years
The 2018 Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member] | Director [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)							3 years
The 2018 Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)	6 years		6 years	6 years	6 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)	$ 25.50	$ 18.25	$ 16.5	$ 18.0	$ 17.6							$ 71.15	[2]	$ 77.22	[2]	$ 68.82	[2]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)	573		45,365	852,475	46,795							513,000	[2]	15,000	[2]	957,000	[2]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Exercise Price (in dollars per share)	$ 90.28		$ 63.40	$ 69.14	$ 68.34											$ 90.28
The 2018 Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)	2 years
The 2018 Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)	4 years
The 2018 Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member] | Director [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)		11,835
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Exercise Price (in dollars per share)		$ 67.54
The 2018 Incentive Plan [Member] | Performance Stock Units (PSU) [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)	$ 96.10		$ 57.3	$ 65.0	$ 73.2							$ 0	[3]	$ 0	[3]	$ 0	[3]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)	1,952		6,540	10,962	5,637							20,000	[3]	0	[3]	25,000	[3]
The 2018 Incentive Plan [Member] | SARs, RSUs, and PSUs [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)			2 years	2 years	2 years
The 2018 Incentive Plan [Member] | SARs, RSUs, and PSUs [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)			4 years	4 years	4 years
The 2018 Incentive Plan [Member] | Stock Appreciation Rights, Expiratiopn Period 2 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)				5 months
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)				1,156
The 2018 Incentive Compensation Plan [Member] | Restricted Stock Units (RSUs) [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)												$ 69.6
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)											72,303
The 2018 Incentive Compensation Plan [Member] | Stock Appreciation Rights (SARs) [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)												22.3
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)											513,385
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Exercise Price (in dollars per share)											$ 71.15
The 2018 Incentive Compensation Plan [Member] | Stock Appreciation Rights (SARs) [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)											6 years
The 2018 Incentive Compensation Plan [Member] | Performance Stock Units (PSU) [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)												$ 75.3
Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)											19,581
The 2018 Incentive Compensation Plan [Member] | Stock Appreciation Rights (SARs), Restricted Stock Units (RSUs), and Performance Stock Units (PSU) [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)											2 years
The 2018 Incentive Compensation Plan [Member] | Stock Appreciation Rights (SARs), Restricted Stock Units (RSUs), and Performance Stock Units (PSU) [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)											4 years

[1] An RSU represents the right to receive one share of common stock once certain vesting conditions are met. The value of an RSU is identical to the value of the underlying stock.

[2] Upon exercise, SARs entitle the recipient to receive shares of common stock equal to the increase in value of the award between the grant date and the exercise date.

[3] The Performance shares units shall be paid out based on achievement of three-year relative total stockholder return compared to other companies in S&P 500 index.