Schedule of Amounts Recognized in the Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Defined Benefit Plan [Abstract]
Plan assets in other long-term assets	$ 938	$ 991
Current portion of pension benefit obligation in wages and benefits payable	3,123	3,260
Long-term portion of pension benefit obligation	94,386	95,717
Pension benefit obligation, net	$ 96,571	$ 97,986

Amount of liability, recognized in statement of financial position, for defined benefit pension plan, classified as current. Excludes other postretirement benefit plan.

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Amount of liability, recognized in statement of financial position, for defined benefit pension plan, classified as noncurrent. Excludes other postretirement benefit plan.

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