Derivatives (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended								3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Prepaid expenses and other current assets [Member]	Dec. 31, 2013 Prepaid expenses and other current assets [Member]	Sep. 30, 2014 Direct financing leases and other assets [Member]	Dec. 31, 2013 Direct financing leases and other assets [Member]	Sep. 30, 2014 Other non-current liabilities [Member]	Dec. 31, 2013 Other non-current liabilities [Member]	Sep. 30, 2014 Interest expense [Member] Interest rate swap [Member]	Sep. 30, 2013 Interest expense [Member] Interest rate swap [Member]	Sep. 30, 2014 Interest expense [Member] Interest rate swap [Member]	Sep. 30, 2013 Interest expense [Member] Interest rate swap [Member]	Sep. 30, 2014 Interest expense [Member] Fixed-rate debt [Member]	Sep. 30, 2013 Interest expense [Member] Fixed-rate debt [Member]	Sep. 30, 2014 Interest expense [Member] Fixed-rate debt [Member]	Sep. 30, 2013 Interest expense [Member] Fixed-rate debt [Member]
Location and amount of gains (losses) on derivative instruments and related hedged items
Derivatives: Interest rate swaps											$ (4,607)	$ 44	$ (4,924)	$ (6,323)
Hedged items: Fixed-rate debt															4,607	(44)	4,924	6,323
Total	0	0	0	0
Interest Rate Fair Value Hedge Asset at Fair Value					1,173	0	4,480	9,333
Interest Rate Derivative Liabilities, at Fair Value									$ (2,406)	$ (1,162)