Business Segment Information (Schedule Of Reportable Segments Financial Information) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Operating revenues	$ 325,723	$ 361,518	$ 630,074	$ 732,415
Direct operating costs	(222,512)	(233,014)	(433,560)	(470,342)
Segment profits	103,211	128,504	196,514	262,073
Depreciation and amortization	52,067	45,536	101,848	89,520
Capital expenditures, (excluding acquisitions)	37,726	39,910	77,599	86,733
Identifiable assets	1,588,995	1,510,382	1,588,995	1,510,382	1,595,918
Completion And Remedial Services [Member]
Segment Reporting Information [Line Items]
Operating revenues	132,216	156,560	250,577	320,980
Direct operating costs	(85,847)	(93,098)	(164,854)	(190,123)
Segment profits	46,369	63,462	85,723	130,857
Depreciation and amortization	15,753	13,644	30,815	26,495
Capital expenditures, (excluding acquisitions)	10,596	12,689	23,583	29,702
Identifiable assets	440,904	436,434	440,904	436,434
Fluid Services [Member]
Segment Reporting Information [Line Items]
Operating revenues	85,601	90,592	169,931	185,917
Direct operating costs	(59,296)	(58,221)	(117,171)	(121,068)
Segment profits	26,305	32,371	52,760	64,849
Depreciation and amortization	14,818	12,530	28,985	24,326
Capital expenditures, (excluding acquisitions)	11,238	10,377	20,356	19,429
Identifiable assets	323,709	253,582	323,709	253,582
Well Servicing [Member]
Segment Reporting Information [Line Items]
Operating revenues	93,921	98,723	181,596	194,625
Direct operating costs	(67,600)	(71,864)	(132,603)	(139,114)
Segment profits	26,321	26,859	48,993	55,511
Depreciation and amortization	15,568	14,574	30,452	28,915
Capital expenditures, (excluding acquisitions)	9,675	8,885	21,700	22,406
Identifiable assets	290,653	306,255	290,653	306,255
Contract Drilling [Member]
Segment Reporting Information [Line Items]
Operating revenues	13,985	15,643	27,970	30,893
Direct operating costs	(9,769)	(9,831)	(18,932)	(20,037)
Segment profits	4,216	5,812	9,038	10,856
Depreciation and amortization	3,318	2,642	6,490	5,390
Capital expenditures, (excluding acquisitions)	(42)	2,890	3,051	7,497
Identifiable assets	61,936	56,712	61,936	56,712
Corporate And Other [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization	2,610	2,146	5,106	4,394
Capital expenditures, (excluding acquisitions)	6,259	5,069	8,909	7,699
Identifiable assets	$ 471,793	$ 457,399	$ 471,793	$ 457,399