Northern's Net Payments Due in Canadian Dollars (Detail) (CAD)	Jun. 30, 2012
Operating Leased Assets [Line Items]
2012	18,345
2013	47,647
2014	10,625
Oilfield equipment
Operating Leased Assets [Line Items]
2012	11,290
2013	45,158
2014	45,158
2015	45,158
2016	45,158
2017	45,158
Subsequent	88,883