Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Buildings, allowance for depreciation	$ 282,804	$ 270,946
Machinery and equipment, allowance for depreciation	$ 620,113	$ 598,137
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	450,000,000	450,000,000
Common stock, shares issued	150,081,474	153,113,042
Common stock, shares outstanding	150,081,474	153,113,042