Property and Equipment (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Property and Equipment
Property and equipment, gross	$ 1,712,477	$ 1,539,275
Less accumulated depreciation and amortization	798,184	682,863
Property and equipment, net	914,293	856,412
Land [Member]
Property and Equipment
Property and equipment, gross	13,747	11,314
Buildings and improvements [Member]
Property and Equipment
Property and equipment, gross	54,359	47,710
Well service units and equipment [Member]
Property and Equipment
Property and equipment, gross	487,648	447,743
Fluid services equipment [Member]
Property and Equipment
Property and equipment, gross	209,125	179,495
Brine and fresh water stations [Member]
Property and Equipment
Property and equipment, gross	14,016	13,000
Frac/test tanks [Member]
Property and Equipment
Property and equipment, gross	267,112	246,816
Pressure pumping equipment [Member]
Property and Equipment
Property and equipment, gross	276,629	246,931
Construction equipment [Member]
Property and Equipment
Property and equipment, gross	29,080	29,281
Contract drilling equipment [Member]
Property and Equipment
Property and equipment, gross	104,188	93,728
Disposal facilities [Member]
Property and Equipment
Property and equipment, gross	90,850	78,632
Vehicles [Member]
Property and Equipment
Property and equipment, gross	61,237	54,238
Rental equipment [Member]
Property and Equipment
Property and equipment, gross	60,543	46,851
Aircraft [Member]
Property and Equipment
Property and equipment, gross	4,151	4,251
Software [Member]
Property and Equipment
Property and equipment, gross	23,853	23,595
Other [Member]
Property and Equipment
Property and equipment, gross	$ 15,939	$ 15,690