Leases Non lease Arrangements Future Commitments (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Non lease Arrangements Future Commitments [Abstract]
Lease Liability	$ 19,057
Other Commitments, Future Minimum Payments, Remainder of Fiscal Year	17,904
Other Commitment, Due in Second Year	23,872	$ 32,093
Other Commitment, Due in Third Year	22,372	26,675
Other Commitment, Due in Fourth Year	20,042	23,355
Other Commitment, Due in Fifth Year	19,520	21,890
Other Commitment, Due after Fifth Year	371	3,299
Other Commitment	$ 104,100	$ 141,500