Business Segment Information (Schedule Of Segment Reporting Information) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Segment Reporting Information [Line Items]
Operating revenues	$ 370,897	$ 246,054
Direct operating costs	(237,328)	(156,086)
Segment profits	133,569	89,968
Depreciation and amortization	43,984	32,980
Capital expenditures, (excluding acquisitions)	46,823	72,442
Identifiable assets	1,457,697	1,070,588	1,459,928
Completion And Remedial Services [Member]
Segment Reporting Information [Line Items]
Operating revenues	164,420	97,507
Direct operating costs	(97,025)	(54,933)
Segment profits	67,395	42,574
Depreciation and amortization	12,851	8,068
Capital expenditures, (excluding acquisitions)	17,013	17,721
Identifiable assets	412,206	213,810
Fluid Services [Member]
Segment Reporting Information [Line Items]
Operating revenues	95,325	72,345
Direct operating costs	(62,847)	(48,228)
Segment profits	32,478	24,117
Depreciation and amortization	11,796	9,404
Capital expenditures, (excluding acquisitions)	9,052	20,656
Identifiable assets	245,063	216,485
Well Servicing [Member]
Segment Reporting Information [Line Items]
Operating revenues	95,902	69,147
Direct operating costs	(67,250)	(48,440)
Segment profits	28,652	20,707
Depreciation and amortization	14,341	11,953
Capital expenditures, (excluding acquisitions)	13,521	26,256
Identifiable assets	301,996	254,407
Contract Drilling [Member]
Segment Reporting Information [Line Items]
Operating revenues	15,250	7,055
Direct operating costs	(10,206)	(4,485)
Segment profits	5,044	2,570
Depreciation and amortization	2,748	1,907
Capital expenditures, (excluding acquisitions)	4,607	4,189
Identifiable assets	62,029	44,246
Corporate And Other [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization	2,248	1,648
Capital expenditures, (excluding acquisitions)	2,630	3,620
Identifiable assets	$ 436,403	$ 341,640