UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 6,053	$ 2,472
Common stock, par value (usd per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	56,926,000	56,176,000
Common stock, shares outstanding (in shares)	54,135,000	53,487,000
Common stock in treasury, at cost (in shares)	2,791,000	2,079,000