Fair Value Disclosure (Details Textual) $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2015 USD ($) Instrument	Jun. 30, 2015 USD ($) Instrument	Dec. 31, 2014 USD ($) Instrument
Fair Value Disclosure (Textual) [Abstract]
Derivative Asset, Notional Amount	$ 550.0	$ 550.0	$ 600.0
Derivative, Notional Amount	346.2	346.2	$ 281.5
Cash Flow Hedge Pre Tax Gain Loss to be Reclassified within Twelve Months		(5.7)
Expected After tax reclassification of net losses from accumulated other comprehensive income to earnings in Next Twelve Months		3.6
Aggregate fair value of all derivative instruments with Net liability position	$ 4.2	$ 4.2
Fair Value Hedging [Member]
Fair Value Disclosure (Textual) [Abstract]
Number of instruments, outstanding | Instrument	8	8
Maturity Date Range of Derivative Instruments
Cash Flow Hedges [Member]
Fair Value Disclosure (Textual) [Abstract]
Number of instruments, outstanding | Instrument	7	7	7
Maturity Date Range of Derivative Instruments