Principles of Consolidation (Fair Value Measurement) (Details) (Fair Value, Measurements, Recurring [Member], USD $) In Millions, unless otherwise specified	Mar. 31, 2015
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted Amounts Held In Escrow, Current, Fair Value Disclosure	$ 17.9
Restricted Amounts Held In Escrow, Non-current, Fair Value Disclosure	60.2
Assets, Fair Value Disclosure	78.1
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted Amounts Held In Escrow, Current, Fair Value Disclosure	0
Restricted Amounts Held In Escrow, Non-current, Fair Value Disclosure	0
Assets, Fair Value Disclosure	0
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted Amounts Held In Escrow, Current, Fair Value Disclosure	0
Restricted Amounts Held In Escrow, Non-current, Fair Value Disclosure	0
Assets, Fair Value Disclosure	0
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted Amounts Held In Escrow, Current, Fair Value Disclosure	17.9
Restricted Amounts Held In Escrow, Non-current, Fair Value Disclosure	60.2
Assets, Fair Value Disclosure	$ 78.1