Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2015	Feb. 26, 2015	Feb. 25, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Financial Position [Abstract]
Common stock, par value (in USD per share)	$ 1.25			$ 1.25
Common Stock, authorized (in shares)	120,000,000	120,000,000	60,000,000	120,000,000
Common stock, outstanding	70,965,622			68,334,860	65,430,084	63,306,524