Annual report pursuant to Section 13 and 15(d)

Commitments And Contingencies (Funding Commitments By Third Parties Or Contingent Events) (Details)

v3.6.0.2
Commitments And Contingencies (Funding Commitments By Third Parties Or Contingent Events) (Details)
$ in Thousands
Dec. 31, 2016
USD ($)
Recorded Unconditional Purchase Obligation [Line Items]  
Unrecorded Unconditional Purchase Obligation $ 42,481
Purchase Obligation, Due in Second and Third Year 11,544
Purchase Obligation, Due in Fourth and Fifth Year 0
Purchase Obligation, Due after Fifth Year 0
Purchase Obligation 54,025
Letters Of Credit And Surety Bonds [Member]  
Recorded Unconditional Purchase Obligation [Line Items]  
Unrecorded Unconditional Purchase Obligation 13,241
Purchase Obligation, Due in Second and Third Year 60
Purchase Obligation, Due in Fourth and Fifth Year 0
Purchase Obligation, Due after Fifth Year 0
Purchase Obligation 13,301
Purchase Obligations [Member]  
Recorded Unconditional Purchase Obligation [Line Items]  
Unrecorded Unconditional Purchase Obligation 29,240
Purchase Obligation, Due in Second and Third Year 11,484
Purchase Obligation, Due in Fourth and Fifth Year 0
Purchase Obligation, Due after Fifth Year 0
Purchase Obligation $ 40,724