Accumulated Other Comprehensive Income (Tables)

12 Months Ended

Dec. 31, 2017

Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]

Components and changes in accumulated other comprehensive income

A summary of the components of and changes in Accumulated other comprehensive income for the past three years follows:

	2015								2016						2017
	Beginning of Year			Changes During		End of Year			Changes During			End of Year			Changes During		End of Year
(In millions)	Balance			Year		Balance			Year			Balance			Year		Balance
Pension & other benefit costs	(2.2		)	0.1		(2.1		)	(0.1		)	(2.2		)	—		(2.2		)
Deferred income taxes	0.9			—		0.9			—			0.9			—		0.9
Accumulated other comprehensive income (loss)	$	(1.3	)	$	0.1	$	(1.2	)	$	(0.1	)	$	(1.3	)	$	—	$	(1.3	)