Leases - Schedule of future minimum lease payments (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Finance Leases
Lessee, Operating Lease, Liability, Payments, Due		$ 269,398
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	$ 76,959	79,209
Finance Lease, Liability, Undiscounted Excess Amount	70	48
Finance Lease, Liability, Payment, Due		1,528
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	11,653
Finance Lease, Liability, Payments, Remainder of Fiscal Year	320
Lessee, Operating Lease, Liability, Payments, Due Year Two	23,222	22,527
Finance Lease, Liability, Payments, Due Year Two	508	508
Lessee, Operating Lease, Liability, Payments, Due Year Five	21,415	20,690
Finance Lease, Liability, Payments, Due Year Five	0	0
Finance Lease, Liability, Payments, Due Next Twelve Months		643
Lessee, Operating Lease, Liability, Payments, Due Year Three	22,578	21,856
Lessee, Operating Lease, Liability, Payments, Due Year Four	22,140	21,415
Finance Lease, Liability, Payments, Due Year Three	279	279
Finance Lease, Liability, Payments, Due Year Four	98	98
Finance Lease, Liability, Payments, Due after Year Five	0	0
Lessee, Operating Lease, Liability, Payments, Due after Year Five	$ 162,810	160,410
Operating Leases, Future Minimum Payments Due, Next Twelve Months		$ 22,500