Commitments and Contingencies - Leases (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Operating Lease Liabilities, Payments Due [Abstract]
2019 (excluding the six months ended June 30, 2019)	$ 8,590
2020	17,345
2021	17,434
2022	17,505
2023	17,578
Thereafter	1,159,743
Total lease payments	1,238,195
Less: Imputed interest	(991,042)
Present value of lease liabilities	$ 247,153
Operating And Capital Leases, Future Minimum Payments Due [Abstract]
2019		$ 18,882
2020		19,091
2021		19,223
2022		19,325
2023		19,429
Thereafter		1,219,303
Total		$ 1,315,253