Consolidated Statement of Shareholders' Equity - 9 months ended Sep. 30, 2017 - USD ($) $ in Millions	Total	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Common Stock [Member]
Beginning Balance at Dec. 31, 2016	$ 1,893.0	$ 625.9	$ (28.2)	$ 1,295.3
Comprehensive Income [Abstract]
Net Income	130.8	130.8
Other Comprehensive Income – Net of Tax [Abstract]
Currency Translation Adjustments	(0.1)		(0.1)
Unrealized Gain on Securities	0.8		0.8
Defined Benefit Pension and Other Postretirement Plans	0.6		0.6
Total Comprehensive Income	132.1
Common Stock Issued	99.0			99.0
Dividends Declared	(81.4)	(81.4)
Ending Balance at Sep. 30, 2017	$ 2,042.7	$ 675.3	$ (26.9)	$ 1,394.3