Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Accounts receivable, reserves	$ 6,784	$ 3,581
Common stock, par value (in USD per share)	$ 0.10	$ 0.10
Common stock, shares authorized (in shares)	120,000,000	120,000,000
Common stock, shares issued (in shares)	106,457,000	105,711,000
Common stock, shares outstanding (in shares)	85,449,000	85,471,000
Deferred stock units, outstanding (in shares)	87,000	143,000
Treasury stock, shares (in shares)	21,008,000	20,240,000