Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) shares in Thousands, $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Parts and supplies, allowance	$ 274	$ 274
Preferred stock, par value (in dollars per share)	$ 0.10	$ 0.10
Preferred stock, shares authorized (in shares)	10,000	10,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	100,000	100,000
Common stock, shares issued (in shares)	30,466	30,420
Common stock, shares outstanding (in shares)	30,466	30,420