CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Allowances	$ 20,921	$ 20,477
Accumulated Depreciation	$ 83,750	$ 80,956
Preferred stock par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock authorized (in shares)	4,000,000	4,000,000
Preferred stock outstanding (in shares)	0	0
Common stock par value (in dollars per share)	$ 0.001	$ 0.001
Common stock authorized (in shares)	250,000,000	250,000,000
Common stock issued (in shares)	104,000,000	103,000,000
Common stock outstanding (in shares)	68,600,000	73,300,000
Treasury stock (in shares)	35,400,000	29,700,000