CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
CONSOLIDATED BALANCE SHEETS
Accounts receivable, related allowances (in dollars)	$ 9,765	$ 12,646
Intangible assets, accumulated amortization (in dollars)	$ 265,940	$ 241,731
Common stock voting, par value (in dollars per share)	$ 0.0025	$ 0.0025
Common stock voting, shares authorized (in shares)	900,000,000	900,000,000
Common stock voting, shares issued (in shares)	262,937,139	261,420,126
Common stock voting, shares outstanding (in shares)	243,089,514	241,449,423
Treasury stock, shares (in shares)	19,847,625	19,970,703