Leases (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Jan. 01, 2011	Jan. 02, 2010
Operating Leased Assets [Line Items]
2012	$ 15,152,000
2013	12,252,000
2014	9,277,000
2015	6,729,000
2016	4,776,000
Thereafter	20,308,000
Total	68,494,000
Operating Leases, Rent Expense, Net	12,300,000	9,700,000	9,400,000
Processing Plants and Storage Locations [Member]
Operating Leased Assets [Line Items]
Number Of Properties Leased	10
Office Locations [Member]
Operating Leased Assets [Line Items]
Number Of Properties Leased	4
Butler Properties [Member]
Operating Leased Assets [Line Items]
Number Of Properties Leased	2
Lease Term	30 years
Lease term, Renewal Option, Number Of Additional Terms	2
Lease term, Renewal Option, Additional Term	10 years
Operating Leases, Rent Expense, Minimum Rentals	30,000
Butler Properties [Member] | Lease Term Of Initial Rental Payment [Member]
Operating Leased Assets [Line Items]
Lease Term	5 years
Butler Properties [Member] | Lease Term Of Increased Rental Payment [Member]
Operating Leased Assets [Line Items]
Lease Term	5 years
Jackson Property [Member]
Operating Leased Assets [Line Items]
Lease Term	30 years
Lease term, Renewal Option, Number Of Additional Terms	2
Lease term, Renewal Option, Additional Term	10 years
Operating Leases, Rent Expense, Minimum Rentals	221,715
Jackson Property [Member] | Lease Term Of Initial Rental Payment [Member]
Operating Leased Assets [Line Items]
Lease Term	5 years
Jackson Property [Member] | Lease Term Of Increased Rental Payment [Member]
Operating Leased Assets [Line Items]
Lease Term	5 years
Henderson Property [Member]
Operating Leased Assets [Line Items]
Lease Term	10 years
Lease term, Renewal Option, Number Of Additional Terms	4
Lease term, Renewal Option, Additional Term	5 years
Operating Leases, Rent Expense, Minimum Rentals	$ 60,000
Henderson Property [Member] | Lease Term Of Initial Rental Payment [Member]
Operating Leased Assets [Line Items]
Lease Term	5 years
Henderson Property [Member] | Lease Term Of Increased Rental Payment [Member]
Operating Leased Assets [Line Items]
Lease Term	5 years