Condensed Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 12.0	$ 11.7	$ 14.4	$ 14.3
Other comprehensive income / (loss), net of tax:
Defined benefit plans adjustments	0.1	0.1	0.1	0.2
Foreign currency translation adjustment gain / (loss)	1.2	(0.8)	(0.1)	(1.3)
Other comprehensive income / (loss), net of tax	1.3	(0.7)	0	(1.1)
Comprehensive income	$ 13.3	$ 11.0	$ 14.4	$ 13.2