Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Receivables, allowance for credit loss	$ 11,709	$ 3,138
Long-term receivables, allowance for credit loss	$ 7,981	$ 8,155
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
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)	40,000,000	40,000,000
Common stock, shares issued (in shares)	24,900,436	24,925,447
Common stock, shares outstanding (in shares)	16,417,618	16,521,921
Treasury stock, shares (in shares)	8,482,818	8,403,526