Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Trade Accounts receivable, allowances	$ 5,095	$ 5,339
Common Stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	400,000,000	200,000,000
Common Stock shares issued	175,112,496	175,112,496
Common Stock, shares outstanding	110,429,596	110,385,344
Treasury stock, shares	64,682,900	64,727,152