Real Estate Investments (Future Lease Payments) (Details) $ in Thousands	Dec. 31, 2015 USD ($) property
Operating Leases, Future Minimum Payments Receivable [Abstract]
2016	$ 1,281,206
2017	1,254,404
2018	1,220,730
2019	1,180,046
2020	1,140,336
Thereafter	8,545,006
Total	14,621,728
Future Minimum Direct Financing Lease Payments
2016	4,505
2017	4,105
2018	3,071
2019	2,397
2020	2,023
Thereafter	5,892
Total	$ 21,993
Number of properties subject to direct financing leases | property	37