Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Allowance for credit losses on accounts receivable and unbilled receivables	$ 3,839	$ 3,227
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares, authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares, issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares, authorized (in shares)	100,000,000	100,000,000
Common Stock, shares, issued (in shares)	52,168,000	51,277,000
Common stock, balance (in shares)	42,274,000	42,132,000
Treasury stock, shares (in shares)	9,894,000	9,145,000