Derivative Financial Instruments Expired Interest Rate Swap Agreements (Details) - Interest Rate Swap 3 [Member] - Swap [Member] $ in Thousands	9 Months Ended
	Sep. 30, 2015 USD ($)
Derivative [Line Items]
Derivative, Inception Date	Sep. 30, 2014
Expiration Date	Sep. 30, 2015
Notional Period 1 [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 1,150,000
Derivative, Forward Interest Rate	0.54%
Notional Period 2 [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 1,100,000
Derivative, Forward Interest Rate	0.54%
Notional Period 3 [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 1,050,000
Derivative, Forward Interest Rate	0.54%
Notional Period 4 [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 1,000,000
Derivative, Forward Interest Rate	0.54%