Non-operating Income (Expense) (Tables)

12 Months Ended

Dec. 31, 2015

Nonoperating Income (Expense) [Abstract]

Schedule of Other Nonoperating Income (Expense) [Table Text Block]

	Year ended December 31,
Dollar amounts in millions	2015			2014			2013
Interest expense	$	(32.0	)	$	(29.9	)	$	(36.2	)
Amortization of debt charges	(1.1		)	(1.2		)	(1.4		)
Capitalized interest	1.9			1.3			1.6
Interest expense, net of capitalized interest	(31.2		)	(29.8		)	(36.0		)
Investment income	4.9			5.5			9.4
SERP market adjustments	(0.5		)	—			0.9
Investment income	4.4			5.5			10.3
Foreign currency losses	(5.3		)	(3.1		)	(5.3		)
Gain on acquisition	—			—			35.9
Gain on the sale of joint venture	—			—			1.2
Early debt extinguishment	—			—			(2.3		)
Other non-operating income (expense)	(5.3		)	(3.1		)	29.5
Total non-operating income (expense)	$	(32.1	)	$	(27.4	)	$	3.8