Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Allowance for doubtful accounts	$ 11,834	$ 12,701
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	95,000,000	95,000,000
Common stock, shares issued	46,892,691	47,654,929
Common stock, shares outstanding	46,892,691	47,654,929
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	1,000,000	1,000,000
Series A Preferred Stock [Member]
Preferred stock, shares authorized	6,000	6,000
Series B Preferred Stock [Member]
Preferred stock, shares authorized	20,000	20,000