Commitments and Contingencies (Future Non-cancelable Lease Payments) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Commitments and Contingencies Disclosure [Abstract]
Pipeline Financing Leases in Year 1	$ 30,817
Pipeline Financing Leases in Year 2	31,992
Pipeline Financing Leases in Year 3	32,591
Pipeline Financing Leases in Year 4	31,233
Pipeline Financing Leases in Year 5	30,678
Pipeline Financing Leases, Thereafter	296,226
Pipeline financing leases, Total minimum lease payments	453,537
Pipeline Financing Leases, Less: Amount representing interest	(217,293)
Present Value Of Future Minimum Lease Payments Sale Leaseback Transactions	236,244
Capital Leases in Year 1	35,429
Capital Leases in Year 2	31,629
Capital Leases in Year 3	30,139
Capital Leases in Year 4	28,038
Capital Leases in Year 5	22,052
Capital Leases, Thereafter	31,806
Capital Leases, Total minimum lease payments	179,093
Capital leases, Less: Amount representing interest	(20,833)
Capital leases, Present value of minimum lease payments	158,260
Operating Leases in Year 1	10,656
Operating Leases in Year 2	11,452
Operating Leases in Year 3	12,300
Operating Leases in Year 4	12,384
Operating Leases in Year 5	12,720
Operating Leases, Thereafter	80,562
Operating Leases, Total minimum lease payments	$ 140,074