Derivative Instruments, Hedging Activities and Fair Value (Details 4) - Designated as hedging instrument	Jun. 30, 2015 USD ($)
Maturing 2018
Derivatives Designated as Hedging Instruments
Contractual Amount	$ 250,000,000.0
Maturing 2020
Derivatives Designated as Hedging Instruments
Contractual Amount	220,000,000.0
Maturing 2016 through 2017
Derivatives Designated as Hedging Instruments
Contractual Amount	$ 7,600,000.0