Note 16 - Stock Based Compensation - Summary of Stock Option Activity (Details) - Employee Stock Option [Member] - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Outstanding, beginning balance (in shares)	1,519,338
Outstanding, beginning balance, weighted average exercise price (in dollars per share)	$ 25.22
Exercisable (in shares)	727,645	701,797
Granted (in shares)	317,331
Granted, weighted average exercise price (in dollars per share)	$ 47.53
Exercised (in shares)	(343,380)
Exercised, weighted average exercise price (in dollars per share)	$ 13.92
Forfeited or expired (in shares)	(8,375)
Forfeited or expired (in dollars per share)	$ 38.13
Outstanding, ending balance (in shares)	1,484,914	1,519,338
Outstanding, ending balance, weighted average exercise price (in dollars per share)	$ 32.53	$ 25.22
Exercisable, weighted average exercise price (in dollars per share)	$ 24.91