Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Allowance for doubtful accounts, current	$ 59,906	$ 45,726
Accumulated amortization of other intangible assets	23,466	19,300
Allowance for doubtful accounts, noncurrent	$ 7,895	$ 6,667
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock authorized (in shares)	100,000,000	100,000,000
Common stock issued (in shares)	75,798,000	75,557,000
Common stock outstanding (in shares)	74,485,000	74,149,000
Common stock in treasury (in shares)	1,313,000	1,408,000