Business Segment Information (Schedule Of Segment Reporting Information By Segment) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Revenues	$ 336,234	$ 372,496	$ 1,091,555	$ 1,002,422
Income (loss) from operations	35,375	100,213	246,059	228,742
Equity in earnings of equity investments	1,392	4,906	7,547	16,443
Contracting Services [Member]
Revenues	221,491	229,967	675,592	532,857
Income (loss) from operations	33,012	47,363	111,359	81,194
Production Facilities [Member]
Revenues	20,024	19,986	60,009	56,101
Income (loss) from operations	10,180	10,983	30,111	28,859
Oil and Gas [Member]
Revenues	119,124	159,218	447,142	500,535
Income (loss) from operations	5,540	48,622	142,924	144,926
Intercompany Elimination [Member]
Revenues	(24,405)	(36,675)	(91,188)	(87,071)
Income (loss) from operations	39	(528)	(2,883)	(457)
Corporate [Member]
Income (loss) from operations	$ (13,396)	$ (6,227)	$ (35,452)	$ (25,780)