Consolidated Statements of Changes in Shareholders’ Equity - USD ($) $ in Millions	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Loss	Noncontrolling Interests
Balance at Dec. 31, 2015	$ 688.2	$ 326.5	$ 548.8	$ (190.4)	$ 3.3
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Net Income	93.3		93.1		0.2
Other comprehensive (loss) income	(6.0)			(6.2)	0.2
Stock issued	17.0	17.0
Stock purchased	(11.7)	(11.3)			(0.4)
Dividends declared	(49.9)	16.6	(66.5)
Balance at Dec. 31, 2016	730.9	348.8	575.4	(196.6)	3.3
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Net Income	71.9		71.6		0.3
Other comprehensive (loss) income	(9.8)			(10.0)	0.2
Stock issued	18.0	17.4			0.6
Stock purchased	(14.0)	(13.7)			(0.3)
Dividends declared	(35.4)	35.2	(70.6)
Balance at Dec. 31, 2017	761.6	387.7	619.9	(250.1)	4.1
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Adoption of ASU 2018-02	0.0		43.5	(43.5)
Net Income	143.7		143.3		0.4
Other comprehensive (loss) income	9.5			9.8	(0.3)
Stock issued	17.8	17.8
Stock purchased	(16.0)	(15.7)			(0.3)
Dividends declared	(46.9)	39.0	(85.9)
Balance at Dec. 31, 2018	870.5	$ 428.8	678.1	(240.3)	$ 3.9
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Adoption of ASU 2018-02				$ 0.0
Adoption of ASC 606, net of tax	$ 0.8		$ 0.8