Segment Information (Details) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 24, 2016 USD ($)	Jun. 26, 2015 USD ($)	Jun. 24, 2016 USD ($) segment	Jun. 26, 2015 USD ($)
Segment information
Number of reportable operating segments \| segment			4
Gross revenue	$ 1,250,283	$ 1,324,048	$ 2,593,691	$ 2,588,034
Equity in earnings of joint ventures and affiliated companies	8,717	10,668	17,770	22,018
Operating income (loss)	(205,120)	29,383	(164,254)	70,248
Energy and Industrial
Segment information
Gross revenue	221,376	292,827	462,017	591,880
Equity in earnings of joint ventures and affiliated companies	304	417	800	832
Operating income (loss)	4,325	11,699	4,786	20,410
Environmental and Nuclear
Segment information
Gross revenue	542,615	396,241	1,045,980	755,201
Equity in earnings of joint ventures and affiliated companies	4,932	7,972	10,961	14,676
Operating income (loss)	21,589	23,622	39,786	40,903
Transportation
Segment information
Gross revenue	224,907	240,205	470,670	475,605
Equity in earnings of joint ventures and affiliated companies	3,079	1,519	4,764	4,016
Operating income (loss)	(59,585)	(30,962)	(56,470)	(37,079)
Water
Segment information
Gross revenue	302,067	359,279	599,308	694,221
Equity in earnings of joint ventures and affiliated companies	402	760	1,245	2,494
Operating income (loss)	20,142	28,816	39,915	48,912
Power EPC
Segment information
Gross revenue	(40,682)	35,496	15,716	71,127
Operating income (loss)	$ (191,591)	$ (3,792)	$ (192,271)	$ (2,898)

This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=35755396&loc=d3e33749-111570

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.12)
-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 9
-Article 5

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 11
-Article 7

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