CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Receivables, allowances	$ 4,215	$ 3,873
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.005	$ 0.005
Common stock, shares authorized	280,000,000	280,000,000
Common stock, shares issued	140,525,055	140,525,055
Treasury stock, shares	22,485,639	23,188,258