Leases - Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Assets:
Operating lease right-of-use assets	$ 1,386,959	$ 628,681
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Operating lease right-of-use assets	Operating lease right-of-use assets
Finance lease assets	$ 181,753	$ 131,072
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Investment Building and Building Improvements	Investment Building and Building Improvements
Total leased assets	$ 1,568,712	$ 759,753
Liabilities:
Operating lease liabilities	$ 1,468,712	$ 693,539
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Operating lease liabilities	Operating lease liabilities
Finance lease liabilities	$ 233,350	$ 178,086
Finance Lease, Liability, Statement of Financial Position [Extensible List]	Accounts Payable and Accrued Liabilities	Accounts Payable and Accrued Liabilities
Total lease liabilities	$ 1,702,062	$ 871,625
Operating lease assets, accumulated depreciation and amortization	148,400	51,700
Finance lease assets, accumulated depreciation and amortization	$ 12,500	$ 4,900