Commitments and Contingencies - Future Lease Payments (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Operating Leased Assets [Line Items]
2012	$ 48,662,000
2013	26,539,000
2014	13,769,000
2015	9,930,000
2016	6,916,000
Thereafter	31,652,000
Total Lease Commitments	137,468,000
Operating Leases, Rent Expense, Net	73,000,000	69,000,000	74,000,000
Chartered Vessel [Member]
Operating Leased Assets [Line Items]
Operating Leases, Operating Lease Term	3 years
Operating Leases, Operating Lease Option, Number	2,000
Operating Leases, Operating Lease Option Term	1 year
Operating Leases, Rent Expense, Minimum Rentals	$ 94,000,000