Leases Future Minimum Lease Rents (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Future Minimum Lease Rents Due [Abstract]
Asset Cost of Leased Property	$ 90.1	$ 89.8
Carrying Amount on Leased Property	67.8	69.5
Contingent Rent Expense on Leases	2.7	2.8	3.4
Minimum Rent Expense on Leases	78.0	81.8	87.2
2012	18.2
2013	18.2
2014	18.0
2015	17.8
2016	17.9
Thereafter	73.3
Total minimum rents receivable	163.4
2012	95.8
2013	95.6
2014	96.1
2015	95.7
2016	95.5
Thereafter	741.4
Total minimum rents receivable	$ 1,220.1