Commitments (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Commitments [Abstract]
Future minimum rental payments required under all operating leases, 2012	$ 6.9
Future minimum rental payments required under all operating leases, 2013	5.8
Future minimum rental payments required under all operating leases, 2014	5.0
Future minimum rental payments required under all operating leases, 2015	3.1
Future minimum rental payments required under all operating leases, 2016	2.0
Future minimum rental payments required under all operating leases, thereafter	4.4
Total rental expense on all operating leases	$ 9.1	$ 8.9	$ 8.1
Service agreement, term	10