Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Allowance for doubtful accounts, trade accounts receivable (in dollars)	$ 2,631	$ 2,003
Preferred stock, par value (In dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000	10,000
Series 2012-A Preferred Stock
Designated shares	8,750	8,750
Preferred stock, shares issued	2,322	2,322
Preferred stock, shares outstanding	2,322	2,322
Class A common stock
Common stock, par value (In dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	35,000	35,000
Common stock, shares issued	1,574	1,574
Common stock, shares outstanding	1,574	1,574
Class B common stock
Common stock, par value (In dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	200,000	200,000
Common stock, shares issued	25,785	25,544
Common stock, shares outstanding	24,755	25,294
Treasury stock, shares	1,030	250