Leases - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Jan. 01, 2019
Ground Lease
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating Lease, Weighted Average Discount Rate, Percent	4.12%
Lease liabilities	$ 76,142
Lease cost	$ 3,200
Weighted average remaining term	79 years 5 months
Office Lease
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating Lease, Weighted Average Discount Rate, Percent	3.65%
Lease liabilities	$ 4,652
Lease cost	$ 700
Weighted average remaining term	9 years 6 months
ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right of use assets		$ 87,500
Lease liabilities		$ 79,700