Income Taxes (Details 5)	12 Months Ended
	Dec. 31, 2011
Canada [Member]
Rollforward of unrecognized tax benefits and associated interest and penalties
Earliest open tax period	1998
Germany [Member]
Rollforward of unrecognized tax benefits and associated interest and penalties
Earliest open tax period	2003
Netherlands [Member]
Rollforward of unrecognized tax benefits and associated interest and penalties
Earliest open tax period	2006
Norway [Member]
Rollforward of unrecognized tax benefits and associated interest and penalties
Earliest open tax period	1999
United Kingdom [Member]
Rollforward of unrecognized tax benefits and associated interest and penalties
Earliest open tax period	2007
United States [Member]
Rollforward of unrecognized tax benefits and associated interest and penalties
Earliest open tax period	2004