Segment Information Information By Segment (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Segment Reporting Information [Line Items]
Revenue, Net	$ 571,640	$ 563,691
Gross profit	183,105	184,978
Operating Income (Loss)	39,621	50,089
Total other income (expense)	(4,420)	(13,396)
Income (Loss) Before Income Taxes	35,201	36,693
Depreciation and amortization	27,227	31,531
Energy Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue, Net	437,747	431,816
Gross profit	134,603	137,584
Operating Income (Loss)	38,164	43,168
Depreciation and amortization	20,656	23,555
Water Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenue, Net	133,893	131,875
Gross profit	48,502	47,394
Operating Income (Loss)	15,937	16,854
Depreciation and amortization	6,556	7,975
Corporate Unallocated [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)	(14,480)	(9,933)
Depreciation and amortization	$ 15	$ 1