Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 537	$ 693
Common stock, par value (in usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	71,268,000	71,134,000
Common stock, shares outstanding (in shares)	30,701,000	33,529,000
Preferred stock, par value (in usd per share)	$ 0.10	$ 0.10
Preferred stock, shares authorized (in shares)	14,399,000	14,399,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Treasury stock, shares of common held at cost (in shares)	40,567,000	37,605,000