Fair Value Measurements (Details 2) (Fair value measurement, recurring basis [Member], Fair Value, Inputs, Level 3 [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2014
Credit valuation adjustment of interest rate swap [Member]
Fair value of financial instruments measured on a recurring basis
Credit Spread	4.00%
Minimum [Member] | Total Return Swap [Member]
Fair value of financial instruments measured on a recurring basis
Bond Valuation	$ 79.59
Minimum [Member] | Fair value adjustment to the borrowings subject to TRS [Member]
Fair value of financial instruments measured on a recurring basis
Bond Valuation	$ 79.59
Maximum [Member] | Total Return Swap [Member]
Fair value of financial instruments measured on a recurring basis
Bond Valuation	$ 108.57
Maximum [Member] | Fair value adjustment to the borrowings subject to TRS [Member]
Fair value of financial instruments measured on a recurring basis
Bond Valuation	$ 108.57
Potential Future Exposure [Member] | Credit valuation adjustment of interest rate swap [Member]
Fair value of financial instruments measured on a recurring basis
Fair value, assets	$ 4,251
Bond Valuation [Member] | Total Return Swap [Member]
Fair value of financial instruments measured on a recurring basis
Fair value, liabilities	(21,434)
Bond Valuation [Member] | Fair value adjustment to the borrowings subject to TRS [Member]
Fair value of financial instruments measured on a recurring basis
Fair value, assets	$ 6,590