Note 5 - Goodwill and Intangible Assets (Details Textual) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization of Intangible Assets	$ 513	$ 398
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	2,053
Finite-Lived Intangible Assets, Amortization Expense, Year Two	2,053
Finite-Lived Intangible Assets, Amortization Expense, Year Three	2,036
Finite-Lived Intangible Assets, Amortization Expense, Year Four	2,031
Finite-Lived Intangible Assets, Amortization Expense, Year Five	$ 1,606