Note 15 - Share-based Payments - Summary of Exercise Prices, Weighted Average Remaining Contractual Life and Intrinsic Values of Outstanding Options (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Number outstanding (in shares)	1,070,045
Weighted average exercise price per share, options outstanding (in dollars per share)	$ 59.88
Weighted average remaining contractual life, options outstanding (Year)	4 years 7 months 6 days
Aggregate intrinsic value, options outstanding	$ 1,196
Number exercisable (in shares)	540,937	438,437
Weighted average remaining contractual life, options exercisable (in dollars per share)	$ 56.40
Weighted average remaining contractual life, options exercisable (Year)	3 years 2 months 12 days
Aggregate intrinsic value, options exercisable	$ 661
Exercise Price Range 01 [Member]
Exercise price - lower limit (in dollars per share)	$ 19.95
Exercise price - upper limit (in dollars per share)	$ 19.95
Number outstanding (in shares)	7,000
Weighted average exercise price per share, options outstanding (in dollars per share)	$ 19.95
Weighted average remaining contractual life, options outstanding (Year)	7 months 6 days
Aggregate intrinsic value, options outstanding	$ 172
Number exercisable (in shares)	7,000
Weighted average remaining contractual life, options exercisable (in dollars per share)	$ 19.95
Weighted average remaining contractual life, options exercisable (Year)	7 months 6 days
Aggregate intrinsic value, options exercisable	$ 172
Exercise Price Range 02 [Member]
Exercise price - lower limit (in dollars per share)	$ 21.10
Exercise price - upper limit (in dollars per share)	$ 21.10
Number outstanding (in shares)	20,892
Weighted average exercise price per share, options outstanding (in dollars per share)	$ 21.10
Weighted average remaining contractual life, options outstanding (Year)	6 months
Aggregate intrinsic value, options outstanding	$ 489
Number exercisable (in shares)	20,892
Weighted average remaining contractual life, options exercisable (in dollars per share)	$ 21.10
Weighted average remaining contractual life, options exercisable (Year)	6 months
Aggregate intrinsic value, options exercisable	$ 489
Exercise Price Range 03 [Member]
Exercise price - lower limit (in dollars per share)	$ 41.97
Exercise price - upper limit (in dollars per share)	$ 48.00
Number outstanding (in shares)	221,480
Weighted average exercise price per share, options outstanding (in dollars per share)	$ 42.24
Weighted average remaining contractual life, options outstanding (Year)	6 years 9 months 18 days
Aggregate intrinsic value, options outstanding	$ 535
Number exercisable (in shares)	7,000
Weighted average remaining contractual life, options exercisable (in dollars per share)	$ 47.29
Weighted average remaining contractual life, options exercisable (Year)	2 years 7 months 6 days
Aggregate intrinsic value, options exercisable	$ 0
Exercise Price Range 04 [Member]
Exercise price - lower limit (in dollars per share)	$ 51.82
Exercise price - upper limit (in dollars per share)	$ 59.98
Number outstanding (in shares)	214,121
Weighted average exercise price per share, options outstanding (in dollars per share)	$ 55.59
Weighted average remaining contractual life, options outstanding (Year)	2 years 1 month 6 days
Aggregate intrinsic value, options outstanding	$ 0
Number exercisable (in shares)	205,921
Weighted average remaining contractual life, options exercisable (in dollars per share)	$ 55.60
Weighted average remaining contractual life, options exercisable (Year)	2 years
Aggregate intrinsic value, options exercisable	$ 0
Exercise Price Range 05 [Member]
Exercise price - lower limit (in dollars per share)	$ 60.01
Exercise price - upper limit (in dollars per share)	$ 68.41
Number outstanding (in shares)	328,702
Weighted average exercise price per share, options outstanding (in dollars per share)	$ 62.05
Weighted average remaining contractual life, options outstanding (Year)	4 years 1 month 6 days
Aggregate intrinsic value, options outstanding	$ 0
Number exercisable (in shares)	230,456
Weighted average remaining contractual life, options exercisable (in dollars per share)	$ 62.63
Weighted average remaining contractual life, options exercisable (Year)	3 years 9 months 18 days
Aggregate intrinsic value, options exercisable	$ 0
Exercise Price Range 06 [Member]
Exercise price - lower limit (in dollars per share)	$ 70.13
Exercise price - upper limit (in dollars per share)	$ 79.51
Number outstanding (in shares)	261,350
Weighted average exercise price per share, options outstanding (in dollars per share)	$ 78.43
Weighted average remaining contractual life, options outstanding (Year)	5 years 8 months 12 days
Aggregate intrinsic value, options outstanding	$ 0
Number exercisable (in shares)	65,918
Weighted average remaining contractual life, options exercisable (in dollars per share)	$ 78.11
Weighted average remaining contractual life, options exercisable (Year)	5 years 9 months 18 days
Aggregate intrinsic value, options exercisable	$ 0
Exercise Price Range 07 [Member]
Exercise price - lower limit (in dollars per share)	$ 80.61
Exercise price - upper limit (in dollars per share)	$ 82.07
Number outstanding (in shares)	16,500
Weighted average exercise price per share, options outstanding (in dollars per share)	$ 81.27
Weighted average remaining contractual life, options outstanding (Year)	6 years 3 months 18 days
Aggregate intrinsic value, options outstanding	$ 0
Number exercisable (in shares)	3,750
Weighted average remaining contractual life, options exercisable (in dollars per share)	$ 82.07
Weighted average remaining contractual life, options exercisable (Year)	6 years 3 months 18 days
Aggregate intrinsic value, options exercisable	$ 0