Note 15 - Stock Based Compensation - Summary of Stock Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Outstanding Options, at Beginning of Period (in shares)	998,480	953,280
Outstanding Options, at Beginning of Period, weighted average exercise price (in dollars per share)	$ 12.82	$ 12.59
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	0	50,000
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price		$ 17.65
Exercised (in shares)
Exercised, weighted average exercise price (in dollars per share)
Forfeited or Expired (in shares)	(167,400)	(4,800)
Forfeited or Expired, weighted average exercise price (in dollars per share)	$ 13.25	$ 17.11
Outstanding Options, at End of Period (in shares)	831,080	998,480
Outstanding Options, at End of Period, weighted average exercise price (in dollars per share)	$ 12.73	$ 12.82
Exerciseable, at End of Period (in shares)	784,698	562,548
Exerciseable, at End of Period, weighted average exercise price (in dollars per share)	$ 12.49	$ 13.79