Long-Term Debt And Other Long-Term Liabilities (Narrative) (Details) (USD $)	6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Long-term Debt	$ 645,900,000	$ 645,700,000
Credit facility maximum credit amount	900,000,000
Commitment fee under credit facility standard	1.00%
Credit facility maturity date	9/13/2016
Origination, agency and syndication and other related fees with the credit agreement	1,500,000
Payable assessment term for LIBOR	90 days
LIBOR interest rate plus one percent	LIBOR plus 1.00%
Line of credit facility, amount outstanding	0	0
Current ratio of credit facility	1 to 1
Leverage ratio of long-term debt	4 to 1
Interest percentage of senior subordinated notes	6.625%
Debt instrument maturity date	May 15, 2021
Original debt issuance fees	14,700,000
Equal redemption price percentage of principal amount of debt	100.00%
Senior notes repurchase price in percentage	101.00%
Estimated principal payments in year 1	14,600,000
Estimated principal payments in year 2	38,800,000
Estimated principal payments in year 3	9,600,000
Estimated principal payments in year 4	7,200,000
Estimated principal payments in year 5	7,400,000
Number of compressors under capital lease agreement	20
Capital lease term	7 years
Capital Lease Obligations, Current	3,100,000
Capital Lease Obligations, Noncurrent	22,700,000
Discount rate capital leases	4.00%
Maintenance	12,285,000
Interest	4,196,000
Capital leases, future minimum payments, average annual payment	4,100,000
Capital lease fair market value percentage for purchase	10.00%
Minimum [Member]
Debt Instrument [Line Items]
Commitment fee percentage under credit facility	0.375%
LIBOR plus interest rate	1.75%
Maximum [Member]
Debt Instrument [Line Items]
Commitment fee percentage under credit facility	0.50%
LIBOR plus interest rate	2.50%
Maximum payment of dividends as a percentage of consolidated net income, prohibited under credit agreement	30.00%
6.625% Senior Subordinated Notes Due 2021 [Member]
Debt Instrument [Line Items]
Aggregate principal amount	650,000,000
Line Of Credit Facility Lender Determined Amount [Member]
Debt Instrument [Line Items]
Credit facility current credit amount	900,000,000	800,000,000
Line Of Credit Facility Commitment Amount [Member]
Debt Instrument [Line Items]
Credit facility current credit amount	$ 500,000,000