CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Trade accounts receivable, allowances for doubtful accounts	$ 10,126	$ 9,015
Shareholders' Equity:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	100,000,000	100,000,000
Common stock, issued (in shares)	17,401,297	17,315,573
Series A preferred Stock
Shareholders' Equity:
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, authorized (in shares)	1,000,000	1,000,000
Series B Convertible Preferred Stock
Shareholders' Equity:
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, authorized (in shares)	1,000,000	1,000,000