Operating Leases (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) years	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Property Subject to or Available for Operating Lease [Line Items]
Number of Properties Subject to Ground Leases	57
Operating Leases, Future Minimum Payments Due, Next Twelve Months	$ 856
Operating Leases, Future Minimum Payments, Due in Two Years	856
Operating Leases, Future Minimum Payments, Due in Three Years	884
Operating Leases, Future Minimum Payments, Due in Four Years	967
Operating Leases, Future Minimum Payments, Due in Five Years	967
Operating Leases, Future Minimum Payments, Due Thereafter	2,658
Operating Leases, Future Minimum Payments Due	7,188
Operating Leases, Future Minimum Payments Receivable [Abstract]
2019	520,139
2020	503,344
2021	492,165
2022	477,671
2023	449,686
Thereafter	3,953,717
Total	$ 6,396,722
Operating Leases, Future Minimum Payments Due [Abstract]
Rental properties, length of lease, minimum (in years) | years	1
Rental properties, length of lease, maximum (in years) | years	31
Rental expense	$ 1,000	$ 1,000	$ 681
Ground Lease Arrangement [Member]
Operating Leases, Future Minimum Payments Due [Abstract]
2019	22,867
2020	23,236
2021	23,600
2022	22,996
2023	22,303
Thereafter	257,446
Total	$ 372,448