Discontinued Operations and Assets and Liabilities Held For Sale (Somar) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Current assets	$ 166,190	$ 116,985
Liabilities held for sale	44,367	$ 24,338
Somar | Disposal Group, Held-for-sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Aggregate purchase price	124,000
Current assets	63,780
Property, plant and equipment	2,347
Other assets	455
Assets held for sale	66,582
Current liabilities	13,933
Liabilities held for sale	$ 13,933