Revenue (Details 2) $ in Thousands	Sep. 30, 2018 USD ($)
Period 1 [Member]
Revenue, Remaining Performance Obligation, Amount	$ 80,242
Period 2 [Member]
Revenue, Remaining Performance Obligation, Amount	256,782
Period 3 [Member]
Revenue, Remaining Performance Obligation, Amount	217,510
Period 4 [Member]
Revenue, Remaining Performance Obligation, Amount	173,283
Period 5 [Member]
Revenue, Remaining Performance Obligation, Amount	161,903
Thereafter [Member]
Revenue, Remaining Performance Obligation, Amount	$ 1,387,769