Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Receivables, allowance for doubtful accounts	$ 24,250	$ 18,482
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	160,000,000	160,000,000
Common stock, shares issued (in shares)	95,065,638	95,065,638
Common stock, shares outstanding (in shares)	55,340,423	55,702,628
Treasury stock, shares (in shares)	39,725,215	39,363,010