Real Estate Real Estate (Future Minimum Lease Payments) (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Future Minimum Lease Payments [Abstract]
Operating Leases, Future Minimum Payments Due, Next Twelve Months	$ 245,167
Operating Leases, Future Minimum Payments, Due in Two Years	248,297
Operating Leases, Future Minimum Payments, Due in Four Years	246,497
Operating Leases, Future Minimum Payments, Due in Five Years	248,414
Operating Leases, Future Minimum Payments, Due in Five Years	251,312
Operating Leases, Future Minimum Payments, Due Thereafter	1,742,065
Operating Leases, Future Minimum Payments Due	$ 2,981,752