Derivative Instruments (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 50
Derivative, Amount of Hedged Item	50
Interest Rate Swap No. 2 [Member]
Derivatives, Fair Value [Line Items]
Derivative, Maturity Date	Aug. 29, 2019
Derivative, Notional Amount	25
Derivative, Fixed Rate and Debt Instrument, Basis Spread on Variable Rate	2.98%
Interest Rate Swap No. 1 [Member]
Derivatives, Fair Value [Line Items]
Derivative, Maturity Date	Aug. 29, 2024
Derivative, Notional Amount	$ 25
Derivative, Fixed Rate and Debt Instrument, Basis Spread on Variable Rate	3.75%