Leases (Schedule of Operating lease right-of-use assets and lease obligations) (Details) $ in Thousands	Mar. 31, 2019 USD ($)
Leases
Right of use asset	$ 72,219
Right of use asset included in balance sheet	us-gaap:OtherAssetsNoncurrent
Current lease liability	$ 16,378
Current lease liability included in balance sheet	us-gaap:AccruedLiabilitiesCurrent
Non current lease liability	$ 56,215
Non current lease liability included in balance sheet	us-gaap:OtherLiabilitiesNoncurrent
Lease liability	$ 72,593