Weighted-Average Assumptions Used To Determine Benefit Obligation (Detail)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Schedule of Benefit Obligations Weighted Average Assumptions [Line Items]
Discount rate	8.85% p.a.	9.30% p.a.
Long-term rate of compensation increase	11% p.a. for first year & 10% for next two years &7%p.a. thereafter	11% p.a. for first year & 9% for next two years &7%p.a. thereafter