Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 751	$ 368
Preferred stock, authorized	4,000,000	4,000,000
Preferred stock, issued	0	0
Common stock, par value	$ 1	$ 1
Common stock, authorized	100,000,000	100,000,000
Common stock, issued	67,221,000	67,570,000