Assets Held For Sale - Summary of Assets and Liabilities Held-for-Sale (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets held for sale:
Total current assets	$ 0	$ 21,060
Liabilities held for sale:
Total current liabilities	$ 0	6,961
Bayou Perma-Pipe Canada, Ltd | Disposed of by Sale
Assets held for sale:
Total current assets		8,559
Property, plant & equipment, less accumulated depreciation		12,501
Total assets held for sale		21,060
Liabilities held for sale:
Total current liabilities		944
Debt		1,924
Deferred income tax liabilities		1,473
Other liabilities		2,620
Total liabilities held for sale		6,961
Non-controlling interests		$ 7,142