Business Segment Information (Schedule Of Reportable Segments Financial Information) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]
Operating revenues	$ 393,955	$ 324,797	$ 1,090,373	$ 954,871
Direct operating costs	(264,120)	(222,743)	(739,237)	(656,303)
Segment profits	129,835	102,054	351,136	298,568
Depreciation and amortization	54,485	53,623	157,975	155,471
Capital expenditures, (excluding acquisitions)	103,730	35,256	224,874	139,869
Identifiable assets	1,605,849	1,562,082	1,605,849	1,562,082	1,543,339
Completion and Remedial Services
Segment Reporting Information [Line Items]
Operating revenues	193,699	127,119	495,550	377,696
Direct operating costs	(119,138)	(82,959)	(308,235)	(247,813)
Segment profits	74,561	44,160	187,315	129,883
Depreciation and amortization	17,530	16,248	50,827	47,063
Capital expenditures, (excluding acquisitions)	62,579	11,422	131,962	40,959
Identifiable assets	515,145	434,083	515,145	434,083
Well Servicing
Segment Reporting Information [Line Items]
Operating revenues	91,119	97,783	273,660	279,379
Direct operating costs	(67,636)	(70,983)	(202,144)	(203,586)
Segment profits	23,483	26,800	71,516	75,793
Depreciation and amortization	14,263	15,494	41,355	45,946
Capital expenditures, (excluding acquisitions)	14,614	6,761	37,876	31,165
Identifiable assets	274,831	282,324	274,831	282,324
Fluid Services
Segment Reporting Information [Line Items]
Operating revenues	92,852	86,121	276,001	256,052
Direct operating costs	(66,121)	(59,673)	(197,958)	(176,844)
Segment profits	26,731	26,448	78,043	79,208
Depreciation and amortization	16,709	15,999	48,445	44,984
Capital expenditures, (excluding acquisitions)	25,010	11,678	46,050	50,388
Identifiable assets	316,152	315,196	316,152	315,196
Contract Drilling
Segment Reporting Information [Line Items]
Operating revenues	16,285	13,774	45,162	41,744
Direct operating costs	(11,225)	(9,128)	(30,900)	(28,060)
Segment profits	5,060	4,646	14,262	13,684
Depreciation and amortization	3,332	3,260	9,661	9,750
Capital expenditures, (excluding acquisitions)	2,033	477	5,641	3,530
Identifiable assets	58,872	60,195	58,872	60,195
Corporate and Other
Segment Reporting Information [Line Items]
Depreciation and amortization	2,651	2,622	7,687	7,728
Capital expenditures, (excluding acquisitions)	(506)	4,918	3,345	13,827
Identifiable assets	$ 440,849	$ 470,284	$ 440,849	$ 470,284