Business Segment Information (Schedule Of Reportable Segments Financial Information) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Operating revenues	$ 324,797	$ 340,400	$ 954,871	$ 1,072,815
Direct operating costs	(222,743)	(222,391)	(656,303)	(692,733)
Segment profits	102,054	118,009	298,568	380,082
Depreciation and amortization	53,623	48,272	155,471	137,792
Capital expenditures, (excluding acquisitions)	35,256	39,961	139,869	126,694
Identifiable assets	1,562,082	1,523,256	1,562,082	1,523,256	1,599,006
Completion And Remedial Services [Member]
Segment Reporting Information [Line Items]
Operating revenues	127,119	143,348	377,696	464,328
Direct operating costs	(82,959)	(86,988)	(247,813)	(277,111)
Segment profits	44,160	56,360	129,883	187,217
Depreciation and amortization	16,248	14,763	47,063	41,258
Capital expenditures, (excluding acquisitions)	11,422	12,276	40,959	41,978
Identifiable assets	434,083	437,153	434,083	437,153
Fluid Services [Member]
Segment Reporting Information [Line Items]
Operating revenues	86,121	84,422	256,052	270,339
Direct operating costs	(59,673)	(57,411)	(176,844)	(178,479)
Segment profits	26,448	27,011	79,208	91,860
Depreciation and amortization	15,999	13,691	44,984	38,016
Capital expenditures, (excluding acquisitions)	11,678	6,729	50,388	26,158
Identifiable assets	315,196	256,422	315,196	256,422
Well Servicing [Member]
Segment Reporting Information [Line Items]
Operating revenues	97,783	97,502	279,379	292,127
Direct operating costs	(70,983)	(67,949)	(203,586)	(207,063)
Segment profits	26,800	29,553	75,793	85,064
Depreciation and amortization	15,494	14,113	45,946	43,028
Capital expenditures, (excluding acquisitions)	6,761	10,036	31,165	32,442
Identifiable assets	282,324	305,578	282,324	305,578
Contract Drilling [Member]
Segment Reporting Information [Line Items]
Operating revenues	13,774	15,128	41,744	46,021
Direct operating costs	(9,128)	(10,043)	(28,060)	(30,080)
Segment profits	4,646	5,085	13,684	15,941
Depreciation and amortization	3,260	3,503	9,750	8,892
Capital expenditures, (excluding acquisitions)	477	3,176	3,530	10,673
Identifiable assets	60,195	62,760	60,195	62,760
Corporate And Other [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization	2,622	2,202	7,728	6,598
Capital expenditures, (excluding acquisitions)	4,918	7,744	13,827	15,443
Identifiable assets	$ 470,284	$ 461,343	$ 470,284	$ 461,343