CONSOLIDATED BALANCE SHEETS (Parenthetical - unaudited) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts (in dollars)	$ 37,530	$ 31,780
Other accounts receivable, allowance for doubtful accounts (in dollars)	542	201
Accumulated depreciation	$ 78,066	$ 76,095
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	34,185,144	34,023,053
Common stock, shares outstanding	34,185,144	34,023,053