Incentive Plans - Schedule of Activity Relating to RSUs and DSUs (Parenthetical) (Detail) (RSUs [Member])	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend participation rights	442,242	920,791	389,846