Fair Value Measurements (Details 2) (Fair value measurement, recurring basis [Member], Fair Value, Inputs, Level 3 [Member], USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014
Credit valuation adjustment of interest rate swap [Member]
Fair value of financial instruments measured on a recurring basis
Fair value, assets	$ 5,283
Valuation technique	Potential future exposure
Unobservable input - credit valuation adjustment of interest rate swap	Credit spread
Input values - credit valuation adjustment of interest rate swap	4.00%
Total Return Swap [Member]
Fair value of financial instruments measured on a recurring basis
Fair value, liabilities	(21,460)
Valuation technique	Bond quote
Total Return Swap [Member] | Discount rate [Member]
Fair value of financial instruments measured on a recurring basis
Unobservable input - TRS	Discount rate
Input values - TRS	N/A	[1]
Total Return Swap [Member] | Capitalization rate [Member]
Fair value of financial instruments measured on a recurring basis
Unobservable input - TRS	Capitalization rate
Input values - TRS	N/A	[1]
Fair value adjustment to the borrowings subject to TRS [Member]
Fair value of financial instruments measured on a recurring basis
Fair value, assets	$ 6,658
Valuation technique	Bond quote
Fair value adjustment to the borrowings subject to TRS [Member] | Discount rate [Member]
Fair value of financial instruments measured on a recurring basis
Unobservable input - fair value adjustment to borrowings subject to TRS	Discount rate
Input values - fair value adjustment to the borrowing subject to TRS	N/A	[1]
Fair value adjustment to the borrowings subject to TRS [Member] | Capitalization rate [Member]
Fair value of financial instruments measured on a recurring basis
Unobservable input - fair value adjustment to borrowings subject to TRS	Capitalization rate
Input values - fair value adjustment to the borrowing subject to TRS	N/A	[1]

[1] The Company does not have access to certain significant unobservable inputs used by these third parties to determine these fair values.