CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement of Comprehensive Income [Abstract]
Net income	$ 112.3	$ 80.7	$ 75.5
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	(0.9)	7.0	(11.8)
Net actuarial gain (loss) arising during period, net of tax of $20.3, $(6.2) and $(17.9)	33.7	(13.2)	(30.1)
Curtailment arising during period, net of tax of $(0.2)	0	0	(0.4)
Settlement effects arising during period, net of tax of $0.3	0	0	0.5
Less: amortization of actuarial loss, net of tax of $3.6, $2.8 and $2.2	4.9	5.7	3.8
Less: amortization of prior service credit, net of tax of $(0.5), $(0.5) and $(0.5)	(0.8)	(0.8)	(0.9)
Less: amortization of transition obligation	0.1	0.1	0.1
Net gains on investment securities, net of tax of $2.1, $0.2 and $0.2	3.5	0.4	0.3
Net gains (losses) on derivatives, net of tax of $1.8, (2.1) and $(1.1)	3.0	(3.6)	(1.7)
Other comprehensive income (loss), net of tax	43.5	(4.4)	(40.2)
Comprehensive income	$ 155.8	$ 76.3	$ 35.3