Note 11 - Share Based Compensation and Employee Benefit Plans - Stock Option (Details)	12 Months Ended
	Dec. 31, 2019 USD ($) $ / shares shares
Balance (in shares) | shares	2,984,280
Balance, weighted average exercise price (in dollars per share) | $ / shares	$ 27.63
Granted (in shares) | shares	482,663
Granted, weighted average exercise price (in dollars per share) | $ / shares	$ 41.15
Exercised (in shares) | shares	(375,950)
Exercised, weighted average exercise price (in dollars per share) | $ / shares	$ 20.19
Forfeited (in shares) | shares	(23,333)
Forfeited, weighted average exercise price (in dollars per share) | $ / shares	$ 33.84
Balance (in shares) | shares	3,067,660
Balance, weighted average exercise price (in dollars per share) | $ / shares	$ 30.62
Balance, weighted average remaining contractual life (Year)	5 years 11 months 15 days
Aggregate intrinsic value | $	$ 48,712,030
Expected to vest (in shares) | shares	1,778,219
Expected to vest, weighted average exercise price (in dollars per share) | $ / shares	$ 34.70
Expected to vest, weighted average remaining contractual life (Year)	7 years 7 months 20 days
Expected to vest, aggregate intrinsic value | $	$ 20,984,383
Vested and exercisable (in shares) | shares	1,259,505
Vested and exercisable, weighted average exercise price (in dollars per share) | $ / shares	$ 24.65
Vested and exercisable, weighted average remaining contractual life (Year)	3 years 6 months 18 days
Vested and exercisable, aggregate intrinsic value | $	$ 27,521,030