Quarterly report pursuant to Section 13 or 15(d)

Commitments And Contingencies (Narrative) (Details)

v3.7.0.1
Commitments And Contingencies (Narrative) (Details)
$ in Thousands
Sep. 30, 2017
USD ($)
Jun. 30, 2017
USD ($)
equipment
Commitments and Contingencies [Line Items]    
Unrecorded Unconditional Purchase Obligation   $ 76,436
Unrecorded Unconditional Purchase Obligation, Due in Remainder of Fiscal Year   10,457
Unrecorded Unconditional Purchase Obligation, Due in Second Years   50,960
Unrecorded Unconditional Purchase Obligation, Due in Third Year   13,219
Unrecorded Unconditional Purchase Obligation Due in Fourth Year   $ 1,800
Unrecorded Unconditional Purchase Obligation, Contingent Upon a Third Party Option, Maximum Quantity | equipment   1
Offshore Support Vessels Fast Support [Member]    
Commitments and Contingencies [Line Items]    
Unrecorded Unconditional Purchase Obligation, Maximum Quantity | equipment   6
Offshore Support Vessels Supply [Member]    
Commitments and Contingencies [Line Items]    
Unrecorded Unconditional Purchase Obligation, Maximum Quantity   0
Unrecorded Unconditional Purchase Obligation, Contingent Upon a Third Party Option   $ 15,400
Wind Farm Utility Vessel [Member]    
Commitments and Contingencies [Line Items]    
Unrecorded Unconditional Purchase Obligation, Maximum Quantity | equipment   1
Subsequent Event [Member]    
Commitments and Contingencies [Line Items]    
Unrecorded Unconditional Purchase Obligation $ 12,300