Leases - Supplemental Balance Sheet Information Related to Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Right of use assets:
Total right of use assets, net	$ 480,861	$ 536,433
Lease liabilities:
Operating leases	320,044	364,803
Financing leases	107,798	108,890
Total	$ 427,842	$ 473,693
Operating lease, right-of-use asset, statement of financial position	well:LeaseRightOfUseAsset	well:LeaseRightOfUseAsset
Finance lease, right-of-use asset, statement of financial position	well:LeaseRightOfUseAsset	well:LeaseRightOfUseAsset
Operating lease, liability, statement of financial position	well:LeaseLiability	well:LeaseLiability
Finance lease, liability, statement of financial position	well:LeaseLiability	well:LeaseLiability
Real estate
Right of use assets:
Operating leases	$ 323,200	$ 374,217
Finance leases	157,661	162,216
Corporate
Right of use assets:
Operating leases	$ 10,328	$ 12,474
Lease liabilities:
Operating lease, right-of-use asset, statement of financial position	well:ReceivablesAndOtherAssets	well:ReceivablesAndOtherAssets
Real estate and Corporate
Right of use assets:
Total right of use assets, net	$ 491,189	$ 548,907