Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Allowance for doubtful accounts receivable	$ 4,629	$ 7,224
Preferred stock, undesignated, par value (in dollars per share)	$ 0.10	$ 0.10
Preferred stock, undesignated, shares authorized (in shares)	2,000,000	2,000,000
Preferred stock, undesignated, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	125,000,000	125,000,000
Common stock, shares issued (in shares)	30,770,323	30,715,959
Common stock, shares outstanding (in shares)	30,770,323	30,715,959