Note 10 - Credit Agreement (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

Schedule of Interest Expense and Commitment Fees on Debt Instrument [Table Text Block]

	Years ended December 31,
	2018		2017		2016
Interest expense	$	9,294	$	7,170	$	4,837
Commitment fees		1,189		1,359		1,518