Leases - Additional balance sheet information (Details) $ in Thousands	Mar. 31, 2020 USD ($)
Assets:
Operating lease assets	$ 648,642
Balance Sheet classification of operating lease assets	us-gaap:OperatingLeaseRightOfUseAsset
Finance lease assets	$ 52,500
Balance Sheet classification of finance lease assets	us-gaap:PropertyPlantAndEquipmentNet
Total lease assets	$ 701,100
Current:
Operating lease liabilities	$ 168,700
Balance Sheet classification of operating lease liabilities	us-gaap:AccruedLiabilitiesCurrent
Finance lease liabilities	$ 19,500
Balance Sheet classification of finance lease liabilities	us-gaap:LongTermDebtAndCapitalLeaseObligationsCurrent
Total current lease liabilities	$ 188,200
Non-current
Operating lease liabilities	$ 738,032
Balance Sheet classification of operating lease liabilities	us-gaap:OperatingLeaseLiabilityNoncurrent
Finance lease liabilities	$ 41,600
Balance Sheet classification of finance lease liabilities	us-gaap:LongTermDebtAndCapitalLeaseObligations
Total non-current lease liabilities	$ 779,600
Weighted average remaining lease term (in years):
Operating leases	7 years 6 months
Finance leases	3 years 1 month 6 days
Weighted average discount rates:
Operating leases	4.60%
Finance leases	4.30%