Note 17 - Stock-based Compensation - SARs Activity (Details) - Stock Appreciation Rights (SARs) [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		6 Months Ended	12 Months Ended		18 Months Ended
		Jun. 30, 2021	Dec. 31, 2020	Dec. 31, 2019	Jun. 30, 2021
Unvested (in shares)		593	641		641
Outstanding, aggregate intrinsic value	[1]	$ 7,706	$ 10,250		$ 10,250
Unvested, grant date weighted average cost (in dollars per share)		$ 4.44	$ 4.10		$ 4.10
Outstanding, weighted average remaining contractual life (Year)		5 years 4 months 24 days		5 years 3 months 18 days	5 years 1 month 6 days
Awarded (in shares)		28	48
Granted, aggregate intrinsic value	[1]	$ 5	$ 154
Shares awarded, grant date weighted average cost (in dollars per share)		$ 9.75	$ 5.80
Exercised (in shares)		(76)	(96)
Exercised, aggregate intrinsic value	[1]	$ 2,815	$ 2,401
Exercised weighted average fair value (in dollars per share)		$ 2.58	$ 2.88
Forfeited (in shares)		0
Vested and exercisable (in shares)		388			388
Vested and exercisable, aggregate intrinsic value	[1]	$ 9,475			$ 9,475
Vested and exercisable, weighted average fair value (in dollars per share)		$ 4.30			$ 4.30
Vested and exercisable, weighted average remaining contractual life (Year)					4 years 4 months 24 days
Unvested (in shares)		157			157
Unvested, aggregate intrinsic value	[1]	$ 1,690			$ 1,690
Unvested, weighted average fair value (in dollars per share)		$ 6.68			$ 6.68
Unvested, weighted average remaining contractual life (Year)		8 years
Unvested (in shares)		545	593	641	545
Outstanding, aggregate intrinsic value	[1]	$ 11,165	$ 7,706	$ 10,250	$ 11,165
Unvested, grant date weighted average cost (in dollars per share)		$ 4.98	$ 4.44	$ 4.10	$ 4.98
Vested in the current year (in shares)		53
Vested in the current year, aggregate intrinsic value	[1]	$ 899
Vested in the current year (in dollars per share)		$ 5.43
Minimum [Member]
Outstanding, exercise price (in dollars per share)		15.24	14.02		14.02
Granted, exercise price (in dollars per share)		50.71	37.30
Exercised, exercise price (in dollars per share)		15.24	14.02
Vested and exercisable, exercise price (in dollars per share)		15.24			15.24
Unvested, exercise price (in dollars per share)		33.08			33.08
Outstanding, exercise price (in dollars per share)		15.24	15.24	14.02	15.24
Vested in the current year, exercise price (in dollars per share)		25.76
Maximum [Member]
Outstanding, exercise price (in dollars per share)		40	40		40
Granted, exercise price (in dollars per share)		50.71	37.30
Exercised, exercise price (in dollars per share)		15.84	25.76
Vested and exercisable, exercise price (in dollars per share)		40			40
Unvested, exercise price (in dollars per share)		50.71			50.71
Outstanding, exercise price (in dollars per share)		50.71	40	40	50.71
Vested in the current year, exercise price (in dollars per share)		40
Weighted Average [Member]
Outstanding, exercise price (in dollars per share)		27.47	25.06		25.06
Granted, exercise price (in dollars per share)		50.71	37.30
Exercised, exercise price (in dollars per share)		15.31	16.33
Forfeited, exercise price (in dollars per share)		0	0
Vested and exercisable, exercise price (in dollars per share)		26.48			26.48
Unvested, exercise price (in dollars per share)		40.11			40.11
Outstanding, exercise price (in dollars per share)		30.40	$ 27.47	$ 25.06	$ 30.40
Vested in the current year, exercise price (in dollars per share)		$ 33.98

[1] Aggregate intrinsic value for SARs is defined as the amount by which the current market price of the underlying stock exceeds the exercise or grant price.