Leases - Summary of Right-of-Use Assets and Related Lease Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Operating Leased Assets [Line Items]
Right-of-use assets	$ 431,753	$ 434,201	$ 0
Lease liabilities	281,620	$ 278,287	$ 0
Corporate Office Leases [Member]
Operating Leased Assets [Line Items]
Right-of-use assets	15,381
Lease liabilities	16,879
Ground Leases [Member]
Operating Leased Assets [Line Items]
Right-of-use assets	416,372
Lease liabilities	$ 264,741