CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Allowances	$ 19,922	$ 18,797
Accumulated Depreciation	81,127	79,604
Intangible assets, accumulated amortization	$ 86,722	$ 82,760
Preferred stock par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock authorized (in shares)	5,000,000.0	5,000,000.0
Preferred stock outstanding (in shares)	0	0
Common stock par value (in dollars per share)	$ 0.001	$ 0.001
Common stock authorized (in shares)	250,000,000.0	250,000,000.0
Common stock issued (in shares)	104,800,000	104,000,000.0
Common stock outstanding (in shares)	67,400,000	68,200,000
Treasury stock (in shares)	37,500,000	35,800,000
Series A convertible preferred stock
Preferred stock authorized (in shares)	1,000,000.0	1,000,000.0