Business Segment Information (Summary Of Financial Data By Segment) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Segment Reporting Information [Line Items]
Revenues	$ 197,429	$ 229,842
Income (loss) from operations	15,238	50,068
Equity in earnings of investments	610	407
Contracting Services [Member]
Segment Reporting Information [Line Items]
Revenues	198,054	244,544
Income (loss) from operations	39,304	59,124
Production Facilities [Member]
Segment Reporting Information [Line Items]
Revenues	20,393	20,022
Income (loss) from operations	11,185	10,049
Intercompany Elimination [Member]
Segment Reporting Information [Line Items]
Revenues	(21,018)	(34,724)
Income (loss) from operations	(1,720)	(3,020)
Corporate [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations	$ (33,531)	$ (16,085)