Leases (Schedule of Operating lease right-of-use assets and lease obligations) (Details) $ in Thousands	Dec. 31, 2019 USD ($)
Leases
Right of use asset	$ 75,176
Right of use asset included in balance sheet	us-gaap:OtherAssetsNoncurrent
Current lease liability	$ 17,532
Current lease liability included in balance sheet	us-gaap:AccruedLiabilitiesCurrent
Non current lease liability	$ 57,897
Non current lease liability included in balance sheet	us-gaap:OtherLiabilitiesNoncurrent
Lease liability	$ 75,429