Commitments And Contingencies (Narrative) (Detail) (USD $)	1 Months Ended	12 Months Ended
	Jul. 31, 2013	Dec. 31, 2013 item	Dec. 31, 2012	Dec. 31, 2011	Oct. 31, 2012
Loss Contingencies [Line Items]
Environmental violations, fines and penalties					$ 1,400,000
Potential liability audit ranges Minimum			5,900,000
Potential liability audit ranges Maximum			7,300,000
Accrual estimated liability			5,900,000
Final settlement		7,400,000
Payments for Legal Settlements	8,000,000
Additional expense		1,500,000
Rent expense		18,200,000	18,500,000	17,200,000
Salary and incentive program severance multiplier		3
Self insurance deductible for workers compensation		5,000,000
Self insurance deductible for general liability claims		1,000,000
Self insurance deductible for medical and dental coverage		350,000
Workers' compensation self-insured risk reserve, short-term		7,000,000	5,900,000
Workers' compensation self-insured risk reserve, long-term		11,300,000	6,900,000
Self insured risk accruals		26,100,000	22,900,000
Receivable for Medical and Dental Coverage		230,000	205,000
Minimum [Member]
Loss Contingencies [Line Items]
Severance payment		0.75
Severance payment for the chance of control		1.5
Maximum [Member]
Loss Contingencies [Line Items]
Severance payment		1.0
Severance payment for the chance of control		2.0
Chief Executive Officer [Member]
Loss Contingencies [Line Items]
Annual salary to Mr. Patterson		$ 650,000
Non-Cancelable Property And Equipment | Minimum [Member]
Loss Contingencies [Line Items]
Term of operating leases		12 months
Non-Cancelable Property And Equipment | Maximum [Member]
Loss Contingencies [Line Items]
Term of operating leases		60 months
Well Service Units And Equipment [Member] | Maximum [Member]
Loss Contingencies [Line Items]
Term of operating leases		99 years