Property And Equipment (Schedule Of Property, Plant And Equipment Under Capital Lease) (Details) (USD $)	3 Months Ended
	Mar. 31, 2012 Y	Mar. 31, 2011	Dec. 31, 2011
Property, Plant and Equipment [Line Items]
Property, plant and equipment under capital lease, gross	$ 166,910,000		$ 157,063,000
Less accumulated amortization	66,646,000		60,455,000
Property, plant and equipment under capital lease, net	100,264,000		96,608,000
Capital leases expiration period, in years	5
Amortization of assets held under capital leases	6,400,000	4,900,000
Light Vehicles [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment under capital lease, gross	31,305,000		28,794,000
Well Service Units And Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment under capital lease, gross	1,671,000		1,671,000
Fluid Services Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment under capital lease, gross	88,078,000		83,544,000
Pressure Pumping Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment under capital lease, gross	26,729,000		24,260,000
Construction Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment under capital lease, gross	1,450,000		1,341,000
Software [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment under capital lease, gross	17,120,000		16,896,000
Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment under capital lease, gross	$ 557,000		$ 557,000