Note 15 - Share-based Payments (Tables)

9 Months Ended

Sep. 30, 2021

Notes Tables

Share-based Payment Arrangement, Option, Activity [Table Text Block]

	Three Months Ended September 30, 2021					Three Months Ended September 30, 2020
	Number of shares			Weighted average exercise price per share		Number of shares			Weighted average exercise price per share
Outstanding, beginning of period		991,097		$	61.81		897,278		$	53.41
Granted		26,675			76.93		23,800			68.30
Exercised		(46,803	)		46.47		(38,102	)		38.58
Forfeited		(14,087	)		68.95		(10,678	)		60.54
Expired		(648	)		56.40		(636	)		58.77
Outstanding, end of period		956,234			62.88		871,662			54.38
Options exercisable, end of period		470,317		$	54.87		436,862		$	48.57

	Nine Months Ended September 30, 2021					Nine Months Ended September 30, 2020
	Number of shares			Weighted average exercise price per share		Number of shares			Weighted average exercise price per share
Outstanding, beginning of period		845,020		$	55.31		754,497		$	49.94
Granted		265,725			79.18		219,325			60.18
Exercised		(120,828	)		45.36		(80,037	)		26.87
Forfeited		(31,649	)		64.54		(18,993	)		60.41
Expired		(2,034	)		60.17		(3,130	)		59.64
Outstanding, end of period		956,234			62.88		871,662			54.38
Options exercisable, end of period		470,317		$	54.87		436,862		$	48.57

Share-based Payment Arrangement, Option, Exercise Price Range [Table Text Block]

	Options outstanding								Options exercisable
Exercise price	Number outstanding		Weighted average exercise price per share		Weighted average remaining contractual life (years)		Aggregate intrinsic value		Number exercisable		Weighted average exercise price per share		Weighted average remaining contractual life (years)		Aggregate intrinsic value
$19.41 - $19.95		24,500	$	19.56		0.6	$	1,455		24,500	$	19.56		0.6	$	1,455
$21.10 - $21.10		20,892		21.10		1.3		1,209		20,892		21.10		1.3		1,209
$37.35 - $37.35		4,375		37.35		0.3		182		4,375		37.35		0.3		182
$46.90 - $48.00		13,000		47.36		4.3		411		7,000		47.29		3.3		222
$51.82 - $59.98		253,656		55.57		2.8		5,930		239,131		55.59		2.7		5,586
$60.01 - $68.41		360,661		62.02		4.8		6,107		164,219		63.07		4.5		2,607
$72.50 - $79.87		279,150		78.69		6.4		185		10,200		72.64		6.2		65
		956,234	$	62.88		4.6	$	15,479		470,317	$	54.87		3.2	$	11,326