Consolidated Balance Sheet (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Trade receivables allowances	$ 14,258	$ 9,995
Common stock, par value, in dollars per share	$ 0.125	$ 0.125
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	115,858,190	115,858,190
Common stock, shares outstanding	78,977,158	79,213,037
Treasury stock, shares at cost	36,881,032	36,645,153