Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Trade Accounts receivable, allowances	$ 4,975	$ 5,497
Common Stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common Stock shares issued	87,556,248	87,556,248
Common Stock, shares outstanding	60,392,905	63,203,361
Treasury stock, shares	27,163,343	24,352,887