Fair Value of Financial Instruments (Schedule of Interest Rate Swaps) (Details)	6 Months Ended
	Jun. 30, 2016 USD ($)
Interest Rate Swaps One [Member]
Derivative [Line Items]
Notional Amount, Liability	$ 300,000,000
Fixed Interest Rate	3.447%
Termination Date	Aug. 06, 2016
Fair Value of Liability	$ 1,000,000
Interest Rate Swaps Two [Member]
Derivative [Line Items]
Notional Amount, Liability	$ 100,000,000
Fixed Interest Rate	3.401%
Termination Date	Aug. 19, 2016
Fair Value of Liability
Interest Rate Swaps Three [Member]
Derivative [Line Items]
Notional Amount, Liability	$ 200,000,000
Fixed Interest Rate	3.429%
Termination Date	Aug. 19, 2016
Fair Value of Liability	$ 1,000,000
Interest Rate Swaps Four [Member]
Derivative [Line Items]
Notional Amount, Liability	$ 200,000,000
Fixed Interest Rate	3.50%
Termination Date	Aug. 30, 2016
Fair Value of Liability	$ 1,000,000
Interest Rate Swaps Five [Member]
Derivative [Line Items]
Notional Amount, Liability	$ 100,000,000
Fixed Interest Rate	3.005%
Termination Date	Nov. 30, 2016
Fair Value of Liability	$ 1,000,000
Interest Rate Swaps Six [Member]
Derivative [Line Items]
Notional Amount, Liability	$ 200,000,000
Fixed Interest Rate	2.055%
Termination Date	Jul. 25, 2019
Fair Value of Liability	$ 7,000,000
Interest Rate Swaps Seven [Member]
Derivative [Line Items]
Notional Amount, Liability	$ 200,000,000
Fixed Interest Rate	2.059%
Termination Date	Jul. 25, 2019
Fair Value of Liability	$ 7,000,000
Interest Rate Swaps Eight [Member]
Derivative [Line Items]
Notional Amount, Liability	$ 400,000,000
Fixed Interest Rate	1.882%
Termination Date	Aug. 30, 2019
Fair Value of Liability	$ 8,000,000
Interest Rate Swaps Nine [Member]
Derivative [Line Items]
Notional Amount, Liability	$ 200,000,000
Fixed Interest Rate	2.515%
Termination Date	Aug. 30, 2019
Fair Value of Liability	$ 8,000,000
Interest Rate Swaps Ten [Member]
Derivative [Line Items]
Notional Amount, Liability	$ 200,000,000
Fixed Interest Rate	2.613%
Termination Date	Aug. 30, 2019
Fair Value of Liability	$ 9,000,000
Interest Rate Swaps Eleven [Member]
Derivative [Line Items]
Notional Amount, Liability	$ 300,000,000
Fixed Interest Rate	2.041%
Termination Date	Aug. 30, 2020
Fair Value of Liability	$ 8,000,000
Interest Rate Swaps Twelve [Member]
Derivative [Line Items]
Notional Amount, Liability	$ 300,000,000
Fixed Interest Rate	2.738%
Termination Date	Aug. 30, 2020
Fair Value of Liability	$ 17,000,000
Interest Rate Swaps Thirteen [Member]
Derivative [Line Items]
Notional Amount, Liability	$ 300,000,000
Fixed Interest Rate	2.892%
Termination Date	Aug. 30, 2020
Fair Value of Liability	$ 18,000,000
Interest Rate Swaps Fourteen [Member]
Derivative [Line Items]
Notional Amount, Liability	$ 300,000,000
Fixed Interest Rate	2.363%
Termination Date	Jan. 27, 2021
Fair Value of Liability	$ 13,000,000
Interest Rate Swaps Fifteen [Member]
Derivative [Line Items]
Notional Amount, Liability	$ 200,000,000
Fixed Interest Rate	2.368%
Termination Date	Jan. 27, 2021
Fair Value of Liability	$ 9,000,000