Leases Future Minimum Lease Rents (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2017 monthly_payment	Dec. 31, 2015 monthly_payment
Future Minimum Lease Rents Due [Abstract]
Asset Cost of Leased Property	$ 90.1	$ 90.1
Carrying Amount on Leased Property	64.5	66.1
Contingent Rent Expense on Leases	2.8	2.8	2.7
Minimum Rent Expense on Leases	75.9	75.4	78.0
2015	18.3
2016	17.8
2017	17.9
2018	17.5
2019	16.3
Thereafter	38.9
Total minimum rents receivable	126.7
2015	101.5
2016	99.7
2017	99.6
2018	98.9
2019	97.1
Thereafter	555.8
Total minimum rents receivable	$ 1,052.6
Forecast
Lease [Line Items]
Number of Monthly Obligation Payments in Fiscal Year				11	13