Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Statement of Other Comprehensive Income [Abstract]
Net income	$ 33.9	$ 26.2	$ 17.7
Other comprehensive income (loss), net of tax:
Defined benefit plans adjustments	(2.9)	(2.7)	0.2
Foreign currency translation adjustment gain (loss)	0.4	(0.3)	1.2
Other comprehensive (loss) income, net of tax	(2.5)	(3.0)	1.4
Comprehensive income	$ 31.4	$ 23.2	$ 19.1