Leases Future Minimum Rent (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Operating Leased Assets
Rental Payments, Capital Leases, 2018	$ 47,095
Rental Payments, Capital Leases, 2019	45,700
Rental Payments, Capital Leases, 2020	46,633
Rental Payments, Capital Leases, 2021	48,221
Rental Payments, Capital Leases, 2022	49,320
Rental Payments, Capital Leases, Thereafter	759,337
Rental Payments, Capital Leases, Total minimum payments	996,306
Less interest	(528,342)
Present value of minimum capital lease payments	467,964
Rental Payments, Operating Leases, 2018	96,265
Rental Payments, Operating Leases, 2019	94,824
Rental Payments, Operating Leases, 2020	93,803
Rental Payments, Operating Leases, 2021	93,255
Rental Payments, Operating Leases, 2022	92,951
Rental Payments, Operating Leases, Thereafter	1,116,173
Rental Payments, Operating Leases, Total minimum payments	1,587,271
Rental Receipts, Capital Leases, 2018	64,511
Rental Receipts, Capital Leases, 2019	65,036
Rental Receipts, Capital Leases, 2020	66,137
Rental Receipts, Capital Leases, 2021	67,929
Rental Receipts, Capital Leases, 2022	69,115
Rental Receipts, Capital Leases, Thereafter	1,048,796
Rental Receipts, Capital Leases, Total minimum payments	1,381,524
Rental Receipts, Operating Leases, 2018	75,583
Rental Receipts, Operating Leases, 2019	75,787
Rental Receipts, Operating Leases, 2020	75,443
Rental Receipts, Operating Leases, 2021	75,133
Rental Receipts, Operating Leases, 2022	75,488
Rental Receipts, Operating Leases, Thereafter	910,200
Rental Receipts, Operating Leases, Total minimum payments	1,287,634
Rental Receipts, Owned Properties, 2018	53,808
Rental Receipts, Owned Properties, 2019	54,779
Rental Receipts, Owned Properties, 2020	55,392
Rental Receipts, Owned Properties, 2021	56,996
Rental Receipts, Owned Properties, 2022	58,574
Rental Receipts, Owned Properties, Thereafter	948,101
Rental Receipts, Owned Properties, Total minimum payments	1,227,650
Current portion of long-term debt
Operating Leased Assets
Capital Lease Obligations, Current	7,422
Long-term Debt
Operating Leased Assets
Capital Lease Obligations, Noncurrent	$ 460,542