Business Segment Information (Schedule Of Reportable Segments Financial Information) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]
Operating revenues	$ 359,662	$ 325,723	$ 696,418	$ 630,074
Direct operating costs	(242,930)	(222,512)	(475,117)	(433,560)
Segment profits	116,732	103,211	221,301	196,514
Depreciation and amortization	51,785	52,067	103,490	101,848
Capital expenditures, (excluding acquisitions)	74,277	37,726	107,384	77,599
Identifiable assets	1,558,856	1,588,995	1,558,856	1,588,995	1,543,339
Completion And Remedial Services [Member]
Segment Reporting Information [Line Items]
Operating revenues	164,366	132,216	301,851	250,577
Direct operating costs	(102,617)	(85,847)	(189,097)	(164,854)
Segment profits	61,749	46,369	112,754	85,723
Depreciation and amortization	16,040	15,753	32,044	30,815
Capital expenditures, (excluding acquisitions)	49,913	10,596	65,308	23,583
Identifiable assets	466,636	440,904	466,636	440,904
Well Servicing [Member]
Segment Reporting Information [Line Items]
Operating revenues	89,629	93,921	182,541	181,596
Direct operating costs	(64,748)	(67,600)	(134,508)	(132,603)
Segment profits	24,881	26,321	48,033	48,993
Depreciation and amortization	13,939	15,568	27,848	30,452
Capital expenditures, (excluding acquisitions)	14,109	9,675	21,804	21,700
Identifiable assets	267,909	290,653	267,909	290,653
Fluid Services [Member]
Segment Reporting Information [Line Items]
Operating revenues	90,314	85,601	183,149	169,931
Direct operating costs	(65,055)	(59,296)	(131,837)	(117,171)
Segment profits	25,259	26,305	51,312	52,760
Depreciation and amortization	15,926	14,818	31,851	28,985
Capital expenditures, (excluding acquisitions)	5,620	11,238	12,859	20,356
Identifiable assets	310,185	323,709	310,185	323,709
Contract Drilling [Member]
Segment Reporting Information [Line Items]
Operating revenues	15,353	13,985	28,877	27,970
Direct operating costs	(10,510)	(9,769)	(19,675)	(18,932)
Segment profits	4,843	4,216	9,202	9,038
Depreciation and amortization	3,214	3,318	6,420	6,490
Capital expenditures, (excluding acquisitions)	2,701	(42)	3,609	3,051
Identifiable assets	57,617	61,936	57,617	61,936
Corporate And Other [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization	2,666	2,610	5,327	5,106
Capital expenditures, (excluding acquisitions)	1,934	6,259	3,804	8,909
Identifiable assets	$ 456,509	$ 471,793	$ 456,509	$ 471,793