Investments - Schedule of Minimum Future Contractual Rent to be Received (Details) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Investments in and Advances to Affiliates, Schedule of Investments [Abstract]  
Remainder of 2015 $ 459,105
2016 600,209
2017 585,456
2018 570,474
2019 550,798
Thereafter 4,320,779
Total future minimum rentals $ 7,086,821