Summary of Significant Accounting Policies Narratives (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jan. 01, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred Costs, Leasing, Net		$ 1,500,000		$ 4,300,000
Land and Land Improvements							$ 16,000,000.0
Operating Lease, Weighted Average Discount Rate, Percent	5.30%		5.30%
Operating right-of-use assets, net (1)	$ 31,795,000		$ 31,795,000		$ 35,300,000	$ 0
Ground lease deferred rent payable	0		0		3,500,000	3,510,000
Other identified intangible assets, net	50,395,000		50,395,000		767,000	55,469,000
Prepaid expenses	$ 20,011,000		$ 20,011,000		$ 140,000	$ 6,482,000
Finance Lease, Weighted Average Discount Rate, Percent	5.80%		5.80%
Operating Lease, Weighted Average Remaining Lease Term	20 years 8 months 12 days		20 years 8 months 12 days
Finance Lease, Weighted Average Remaining Lease Term	7 years 3 months 18 days		7 years 3 months 18 days
Fixed Operating and Finance Lease, Cost	$ 662,000		$ 1,900,000
Variable operating lease costs	$ 437,000		$ 1,300,000